New uses of lurasidone or a pharmaceutically acceptable salt thereof

Abstract

The application provides a new use of lurasidone or a pharmaceutically acceptable salt thereof. The application of lurasidone or a pharmaceutically acceptable salt thereof in the preparation of a drug for treating type 3 long QT syndrome. Lurasidone or a pharmaceutically acceptable salt thereof has high safety, and provides a new therapy for the treatment of type 3 long QT syndrome.

Description

Technical Field

[0001] This application relates to the field of biomedical technology, and specifically to novel uses of lurasidone or pharmaceutically acceptable salts thereof. Background Technology

[0002] Long QT syndrome (LQTS) is a group of inherited cardiac ion channelopathies characterized by prolonged QTc interval on electrocardiogram (ECG) and a predisposition to malignant ventricular arrhythmias, particularly torsades de pointes (TDPT). LQTS is mainly divided into congenital LQTS caused by genetic mutations and acquired LQTS caused by acquired factors. At least 17 subtypes of congenital LQTS have been identified, with the most common being type 1 (LQT1), type 2 (LQT2), and type 3 (LQT3).

[0003] Voltage-gated sodium channels (Nav) are proteins that are widely present in the human body and can generate action potentials in cells. There are nine subtypes of Nav in the human body, named Nav1.1 to Nav1.9, among which Nav1.5 mainly plays a role in the heart.

[0004] LQT3 is caused by a gain-of-function mutation in the SCN5A gene, which encodes the cardiac sodium channel Nav1.5. This type of mutation leads to an abnormal increase in the late sodium current (INa-L) of the sodium channel, prolonging the action potential duration, and thus becomes a key target for drug intervention.

[0005] Currently, standardized treatment for LQT3 primarily relies on sodium channel blockers (such as mexiletine and ranolazine), but existing drugs have limitations such as insufficient selectivity, risk of proarrhythmia, and significant individual variability. Therefore, exploring new therapeutic agents that combine safety and efficacy is of significant clinical value. Summary of the Invention

[0006] In view of this, this application provides a new use for lurasidone or a pharmaceutically acceptable salt thereof, which can be used in the preparation of Nav1.5 inhibitors and in the preparation of drugs for the treatment of type 3 long QT syndrome, providing a new approach for the clinical treatment of type 3 long QT syndrome.

[0007] In one aspect, this application provides the use of lurasidone or a pharmaceutically acceptable salt thereof in the preparation of a medicament for treating type 3 long QT syndrome.

[0008] Optionally, lurasidone or a pharmaceutically acceptable salt thereof can treat type 3 long QT syndrome by inhibiting abnormally increased late sodium currents, thereby shortening the prolonged myocardial action potential duration and QT interval.

[0009] Optionally, the lurasidone or a pharmaceutically acceptable salt thereof binds to Nav1.5 to promote conformational correction of the SCN5A mutant protein, inhibit abnormally increased late sodium current, and treat type 3 long QT syndrome.

[0010] Optionally, the lurasidone or a pharmaceutically acceptable salt thereof may be used as a single active ingredient or together with other pharmaceutically acceptable active ingredients to constitute the medicament for treating type 3 long QT syndrome.

[0011] Optionally, the mass content of lurasidone or a pharmaceutically acceptable salt thereof in the drug for treating type 3 long QT syndrome is 0.01%-100%.

[0012] Optionally, the medication for treating type 3 long QT syndrome may also include pharmaceutically acceptable excipients.

[0013] Optionally, the excipients include at least one of diluents, solubilizers, binders, disintegrants, lubricants, wetting agents, flavoring agents, emulsifiers, antioxidants, preservatives, and pH adjusters.

[0014] Optionally, the form of the medicine for treating type 3 long QT syndrome includes at least one of injections, tablets, granules, capsules, oral liquids, and pills.

[0015] Optionally, the medication for treating type 3 long QT syndrome is administered orally or by injection.

[0016] Secondly, this application provides the use of lurasidone or a pharmaceutically acceptable salt thereof in the preparation of Nav1.5 inhibitors.

[0017] Thirdly, this application provides a medicament comprising lurasidone or a pharmaceutically acceptable salt thereof, said medicament for treating type 3 long QT syndrome or said medicament being a Nav1.5 inhibitor.

[0018] This application provides a new use of lurasidone or a pharmaceutically acceptable salt thereof, which can be used in the preparation of medicaments for the treatment of type 3 long QT syndrome and in the preparation of Nav1.5 inhibitors. Lurasidone or a pharmaceutically acceptable salt thereof has a high safety profile and provides a new therapy for the treatment of type 3 long QT syndrome, which is beneficial to the treatment of type 3 long QT syndrome. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0020] Figure 1 This is the concentration-inhibition rate curve from Experiment 2.

[0021] Figure 2 This is the current-voltage curve for Experiment 3.

[0022] Figure 3 This is the steady-state activation curve for Experiment 4.

[0023] Figure 4 This is the steady-state deactivation curve for Experiment 4.

[0024] Figure 5 The image shows the recovery curve after the sodium channel current was deactivated in Experiment 4.

[0025] Figure 6 The image shows the sodium current in Experiment 4.

[0026] Figure 7 This is the root mean square deviation plot.

[0027] Figure 8 This is a root mean square fluctuation plot.

[0028] Figure 9 This is a diagram showing the radius of rotation.

[0029] Figure 10 This is a diagram of the solvent-accessible surface area.

[0030] Figure 11 This is a landscape image of WT's free energy.

[0031] Figure 12 This is a free energy landscape image of SCN5A p.V411M.

[0032] Figure 13 A landscape diagram of the free energy of the SCN5A p.V411M+ lurasidone system.

[0033] Figure 14 The results are for molecular docking.

[0034] Figure 15 This is a diagram showing the energy decomposition of residues.

[0035] Figure 16 This is a diagram showing the energy component decomposition. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0037] This application provides the use of lurasidone or a pharmaceutically acceptable salt thereof in the preparation of a medicament for the treatment of type 3 long QT syndrome.

[0038] The molecular formula of lurasidone is C 28 H 36 N4O2S, the structural formula is shown in formula (I). Formula (I).

[0039] The pharmaceutically acceptable salts in this application may be selected from at least one of the following: hydrochloride, hydrobromide, sulfate, citrate, tartrate, phosphate, lactate, pyruvate, acetate, succinate, oxalate, fumaric acid, maleate, oxaloacetate, methanesulfonate, ethanesulfonate, benzenesulfonate, and hydroxyethanesulfonate. Specifically, salts formed by lurasidone with any of the following acids: hydrochloric acid, hydrobromic acid, sulfuric acid, citric acid, tartaric acid, phosphoric acid, lactic acid, pyruvate, acetic acid, succinic acid, oxalic acid, fumaric acid, maleic acid, oxaloacetate, methanesulfonate, ethanesulfonate, benzenesulfonate, and hydroxyethanesulfonate.

[0040] Type 3 long QT syndrome is caused by mutations in the SCN5A gene encoding Nav1.5, including but not limited to p.K1505_P1507del, N1325S, R1644H, E1784K, V1763M, R1623Q, and V411M mutations. Lurasidone, as a novel second-generation antipsychotic, plays an important role in the treatment of schizophrenia and bipolar disorder. Current research has shown that lurasidone or its pharmaceutically acceptable salts have a high metabolic safety profile, thus providing a new, safe, and effective treatment option for type 3 long QT syndrome.

[0041] In some embodiments of this application, lurasidone or a pharmaceutically acceptable salt thereof treats type 3 long QT syndrome by inhibiting abnormally increased late sodium current, thereby shortening the prolonged myocardial action potential duration and QT interval. Type 3 long QT syndrome is characterized by abnormally increased late sodium current, resulting in prolonged myocardial action potential duration (APD) and QT interval; lurasidone or a pharmaceutically acceptable salt thereof can inhibit abnormally increased late sodium current, thereby shortening the prolonged myocardial action potential duration and QT interval, achieving the therapeutic effect of treating type 3 long QT syndrome.

[0042] In some embodiments of this application, lurasidone or a pharmaceutically acceptable salt thereof binds to Nav1.5, promoting conformational correction of the SCN5A mutant protein, inhibiting abnormally increased late sodium current, and treating type 3 long QT syndrome. The inventors have discovered that lurasidone or a pharmaceutically acceptable salt thereof can bind to Nav1.5 through multi-point hydrophobic embedding and pocket-filling effects, optimizing the spatial stacking of local amino acid residues, alleviating mutation-induced abnormal contraction of the local channel structure, and restoring the conformational characteristics of the mutant protein to the wild-type state. This promotes conformational correction of the SCN5A mutant protein, achieving the effect of inhibiting abnormally increased late sodium current, which is beneficial for the treatment of type 3 long QT syndrome.

[0043] In some embodiments of this application, lurasidone or a pharmaceutically acceptable salt thereof constitutes a medicament for treating type 3 long QT syndrome as a single active ingredient or in combination with other pharmaceutically acceptable active ingredients. In some embodiments, lurasidone or a pharmaceutically acceptable salt thereof is the sole active ingredient of the medicament for treating type 3 long QT syndrome. In other embodiments, lurasidone or a pharmaceutically acceptable salt thereof constitutes a medicament for treating type 3 long QT syndrome in combination with other pharmaceutically acceptable active ingredients, which is beneficial for treating type 3 long QT syndrome from multiple routes and improves the therapeutic effect of the medicament on type 3 long QT syndrome. Other pharmaceutically acceptable active ingredients have the effect of treating type 3 long QT syndrome. Exemplarily, other pharmaceutically acceptable active ingredients may be, but are not limited to, at least one selected from mexiletine, ranolazine, etc.

[0044] In this application, the amount of lurasidone or a pharmaceutically acceptable salt thereof in the drug for treating type 3 long QT syndrome is determined based on the drug tolerance and severity of the disease in the recipient. The drug for treating type 3 long QT syndrome only needs to contain a therapeutically effective amount of lurasidone or a pharmaceutically acceptable salt thereof. In some embodiments of this application, the mass content of lurasidone or a pharmaceutically acceptable salt thereof in the drug for treating type 3 long QT syndrome is 0.01%-100%. For example, the mass content of lurasidone or a pharmaceutically acceptable salt thereof in the drug for treating type 3 long QT syndrome may be, but is not limited to, 0.01%, 0.05%, 0.1%, 1%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%. In some embodiments, the mass content of lurasidone or a pharmaceutically acceptable salt thereof in the medicament for treating type 3 long QT syndrome may be 0.1%-90%.

[0045] In some embodiments of this application, the medicament for treating type 3 long QT syndrome further includes pharmaceutically acceptable excipients. These pharmaceutically acceptable excipients are used for transporting, stabilizing, and / or diluting lurasidone or its pharmaceutically acceptable salts, enabling lurasidone or its pharmaceutically acceptable salts to exert their intended effect and ensuring the efficacy of the medicament. The excipients are compatible with lurasidone or its pharmaceutically acceptable salts and do not affect the activity of lurasidone or its pharmaceutically acceptable salts. Furthermore, the excipients are non-toxic and do not react with lurasidone or its pharmaceutically acceptable salts to cause toxic side effects.

[0046] In some embodiments of this application, the excipients include at least one selected from diluents, solubilizers, binders, disintegrants, lubricants, wetting agents, flavoring agents, emulsifiers, antioxidants, preservatives, and pH adjusters. For example, the diluent may be, but is not limited to, water, physiological saline, starch, sugars, cellulose, etc.; the solubilizer may be, but is not limited to, lactic acid, cyclodextrin, povidone, etc.; the binder may be, but is not limited to, hydroxymethyl cellulose, alginate, gelatin, polyvinylpyrrolidone, sucrose, gum arabic, etc.; the disintegrant may be, but is not limited to, agar, calcium carbonate, starch, alginic acid, sodium carbonate, etc.; the lubricant may be, but is not limited to, hyaluronic acid, magnesium stearate, calcium stearate, polyethylene glycol, sodium dodecyl sulfate, etc.; and the wetting agent may be, but is not limited to, polysaccharide. Pear esters, glyceryl monostearate, soybean lecithin, etc.; flavoring agents may be selected from, but are not limited to, sucrose, fructose, glucose, fruit flavorings, etc.; emulsifiers may be selected from, but are not limited to, gum arabic, gelatin, sodium lauryl sulfate, etc.; antioxidants may be selected from, but are not limited to, vitamin C, vitamin E, sulfites, etc.; preservatives may be selected from, but are not limited to, benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, etc.; pH adjusters may be selected from, but are not limited to, hydrochloric acid, phosphoric acid, citric acid, tartaric acid, acetic acid, sodium hydroxide, potassium hydroxide, sodium bicarbonate, disodium hydrogen phosphate, etc.

[0047] In some embodiments of this application, the form of the medicine for treating type 3 long QT syndrome includes at least one of the following: injection, tablet, granule, capsule, oral liquid, and pill. The specific form of the medicine depends on the actual application requirements.

[0048] In some embodiments of this application, the medicament for treating type 3 long QT syndrome is administered orally or by injection. When administered orally, the dosage form of the medicament for treating type 3 long QT syndrome can be solid or liquid. In some embodiments, injection can be administered, but is not limited to, intraperitoneal injection, subcutaneous injection, intramuscular injection, or intravenous injection. In other embodiments, the medicament for treating type 3 long QT syndrome can be dissolved in a solvent, such as water or saline, which facilitates injection. In still other embodiments, the medicament for treating type 3 long QT syndrome can be administered locally or systemically.

[0049] This application provides the use of lurasidone or a pharmaceutically acceptable salt thereof in the preparation of Nav1.5 inhibitors. The Nav1.5 inhibitors are used to inhibit voltage-gated sodium channel 1.5 subtype receptors.

[0050] In some embodiments of this application, lurasidone or a pharmaceutically acceptable salt thereof inhibits late sodium current. That is, lurasidone or a pharmaceutically acceptable salt thereof can reduce abnormally increased late sodium current.

[0051] In some embodiments of this application, lurasidone or a pharmaceutically acceptable salt thereof binds to Nav1.5, promoting conformational correction of the SCN5A mutant protein and inhibiting late sodium current. The inventors have discovered that lurasidone or a pharmaceutically acceptable salt thereof can bind to Nav1.5 through multi-point hydrophobic embedding and pocket-filling effects, optimizing the spatial stacking of local amino acid residues, alleviating mutation-induced abnormal contraction of the channel's local structure, and restoring the conformational characteristics of the mutant protein to the wild-type state. This promotes conformational correction of the SCN5A mutant protein, achieving the effect of inhibiting abnormally increased late sodium current.

[0052] In some embodiments of this application, lurasidone or a pharmaceutically acceptable salt thereof constitutes a Nav1.5 inhibitor as a single active ingredient or with other pharmaceutically acceptable degradation components. In some embodiments, lurasidone or a pharmaceutically acceptable salt thereof is the sole active ingredient of the Nav1.5 inhibitor. In other embodiments, lurasidone or a pharmaceutically acceptable salt thereof constitutes a Nav1.5 inhibitor with other pharmaceutically acceptable degradation components, which is advantageous for inhibiting Nav1.5 through multiple pathways. These other pharmaceutically acceptable degradation components have an inhibitory effect on Nav1.5.

[0053] In this application, the amount of lurasidone or a pharmaceutically acceptable salt thereof in the Nav1.5 inhibitor is determined based on the drug tolerance and disease severity of the recipient, and the Nav1.5 inhibitor only needs to contain a therapeutically effective amount of lurasidone or a pharmaceutically acceptable salt thereof. In some embodiments of this application, the mass content of lurasidone or a pharmaceutically acceptable salt thereof in the Nav1.5 inhibitor is 0.01%-100%. Exemplarily, the mass content of lurasidone or a pharmaceutically acceptable salt thereof in the Nav1.5 inhibitor may be, but is not limited to, 0.01%, 0.05%, 0.1%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%. In some embodiments, the mass content of lurasidone or a pharmaceutically acceptable salt thereof in the Nav1.5 inhibitor may be 0.1%-90%.

[0054] In some embodiments of this application, the Nav1.5 inhibitor also includes pharmaceutically acceptable excipients. These excipients have been described above and will not be repeated here.

[0055] In some embodiments of this application, the Nav1.5 inhibitor is in the form of at least one of injections, tablets, granules, capsules, oral liquids, and pills. The specific form of the drug depends on the actual application requirements.

[0056] In some embodiments of this application, the Nav1.5 inhibitor is administered orally or by injection. When administered orally, the Nav1.5 inhibitor may be in solid or liquid form. In some embodiments, injection may be administered, but is not limited to, intraperitoneal, subcutaneous, intramuscular, or intravenous injection. In other embodiments, the Nav1.5 inhibitor may be dissolved in a solvent, such as water or saline, to facilitate injection. In still other embodiments, the Nav1.5 inhibitor may be used by local or systemic administration.

[0057] This application provides a medicament comprising lurasidone or a pharmaceutically acceptable salt thereof, said medicament for treating type 3 long QT syndrome or said medicament being a Nav1.5 inhibitor. In other words, this application provides a medicament for treating type 3 long QT syndrome comprising lurasidone or a pharmaceutically acceptable salt thereof; this application also provides a Nav1.5 inhibitor comprising lurasidone or a pharmaceutically acceptable salt thereof. The mass content of lurasidone or its pharmaceutically acceptable salt in the medicament, the pharmaceutically acceptable excipients, the form of the medicament, etc., are as described above and will not be repeated here.

[0058] The following specific examples further illustrate the effects of the technical solution in this application.

[0059] Experiment 1 screened candidate drugs targeting the hNav1.5 protein; Initial screening was performed using MTiOpenScreen automated ligand docking to the entire protein surface. The top 1500 compounds were then further refined through redundancy removal, drug similarity assessment, filtering for cardiotoxic drugs, and analysis of drug mechanisms of action and chemical diversity, resulting in 49 drug molecules. Autodock Vina 1.1.2 was used for further docking evaluation of these 49 drug molecules. The docking cassette completely encapsulated the receptor protein, with the ligand placed outside the cassette. Binding energy represents the probability of receptor-ligand interaction; lower energy indicates stronger binding affinity and higher binding stability. To ensure accuracy, a Lamarckian genetic algorithm was used to perform 50 independent docking calculations for each ligand. The docking posture with the lowest binding energy was selected as the optimal binding mode for subsequent analysis. Binding energy was used for ranking, and visual inspection was combined to exclude potential high-ranking false positives.

[0060] The docking results were visualized using PyMOL 3.0.4. Drugs with binding sites located in the drug-forming cavity, extracellular domain, and channel pore domain of the human Nav1.5 (hNav1.5) protein were preferentially selected. After CavityPlus strong drug-forming cavity alignment and binding site distribution domain sorting, 37 drug molecules were finally obtained. After removing drugs discontinued in clinical trials and those not yet marketed, and following further literature searches for drug functions, 10 drugs were selected as target drugs for high-throughput patch-clamp screening: telmisartan, mozavaptan, lurasidone, dihydroergocristine mesylate, brefonalol HCl, conivaptan hydrochloride, azilsartan medoxomil, lumacaftor, rimegepant, and liafensine. Tetridostigmine (TTX) was used as a positive control to clarify the inhibitory / activating effects of the drug molecules on hNav1.5 protein function.

[0061] Experiment 2: Lurasidone blocked the hNav1.5 current in a concentration-dependent manner; Chinese hamster lung (CHL) cells stably expressing hNav1.5 were subjected to experiments with the aforementioned 10 drugs. Using whole-cell patch-clamp technology, a test pulse ranging from depolarization at the clamping potential to -15 mV and lasting for 15 ms was applied to CHL cells to induce inward sodium currents. The peak current and the rate of current decay over 15 ms were recorded to assess the effect of different drugs on the Nav1.5 current amplitude. High-throughput patch-clamp screening ultimately determined that lurasidone had a significantly better inhibitory effect than the other nine drugs. Specifically, in a 10 μmol / L lurasidone solution, the rate of current change after 15 ms of voltage stimulation was 72.6% (n=15), demonstrating that lurasidone inhibits the hNav1.5 sodium channel current. Given the good inhibitory effect of lurasidone, further research was conducted to more thoroughly evaluate its impact on the biophysical properties of hNav1.5.

[0062] CHL cells were inoculated with lurasidone solutions of varying concentrations (1 μmol / L–10 μmol / L gradients), with an equal volume of physiological saline as a control. The inhibition rate of hNav1.5 current amplitude was recorded using whole-cell patch-clamp technology. The entire whole-cell pattern formation process was automated by the SyncroPatch 384 instrument. After obtaining the whole-cell recording pattern, the cells were clamped at -95 mV, and then a 30 ms depolarization step voltage was applied to -10 mV to induce sodium current. This voltage stimulation was applied every 10 s, and after 1 min of recording, extracellular fluid was applied for 3 min of recording. Then, the drug administration process began, starting with the lowest test concentration, and each test concentration was administered for 3 min. After all concentrations were administered, a positive control compound was given. At least 3 cells (n≥3) were tested for each concentration. Simultaneously, a concentration-inhibition rate curve was plotted against the corresponding lurasidone concentration (n=15 for each concentration), as shown below. Figure 1 As shown.

[0063] High-throughput patch-clamp screening showed that lurasidone blocked hNav1.5 current in a concentration-dependent manner, with 10 μmol / L lurasidone reducing the hNav1.5 current amplitude by up to approximately 72.6%. Figure 1 The curve shown can be well fitted by the Hill equation (Hill slope is 0.898), and the half-maximal inhibitory concentration (IC50) of lurasidone on the sodium current of hNav1.5 can be obtained as 7.05 μmol / L.

[0064] Experiment 3: Effect of lurasidone on the function of gain-of-function SCN5A p.V411M protein; Our team's previous research has demonstrated that SCN5A p.V411M is a gain-of-function mutation (Zhou Hui, Li Zhang, AliRaza Ghani, et al. A family report of type 3 long QT syndrome with high incidence of sudden cardiac death [J]. Chinese Journal of Cardiovascular Diseases, 2015, 43(12): 1046-1050. DOI: 10.3760 / cma.j.issn.0253-3758.2015.12.008). The results of this article indicate that, compared with WT, the SCN5A p.V411M mutant leads to an inward sodium ion current density (I0.05). Na The significant increase demonstrates a clear "functional enhancement" effect.

[0065] To evaluate the acute inhibitory efficacy of lurasidone against SCN5A p.V411M-mutated sodium channels, HEK293 cells with the SCN5A p.V411M mutation (SCN5A p.V411M + lurasidone) were incubated with 10 μmol / L lurasidone solution for 24 h. Cell currents were recorded using a German HEKA-EPC10 patch-clamp system in voltage-clamp mode. Cells were clamped at -120 mV, and the stimulation voltage was increased from -100 mV to +50 mV in 10 mV increments, with a pulse duration of 50 ms. The peak whole-cell current at different voltages, and the ratio of the current amplitude to the cell membrane capacitance at the corresponding voltage, were used as the current density (pA / pF). Channel current-voltage (IV) curves were plotted. The results are shown below. Figure 2 As shown, HEK293 cells with the SCN5A p.V411M mutation (SCN5A p.V411M), HEK293 cells without the SCN5A mutation (WT), and HEK293 cells without the SCN5A mutation that underwent the same lurasidone incubation procedure (WT + lurasidone) served as controls. It can be seen that lurasidone has a higher peak I response to the SCN5A p.V411M mutant. Na The average inhibition efficiency was 89.25% ± 31.57% (n ≥ 3, P < 0.01), indicating that lurasidone significantly blocked the sodium channel of the SCN5A p.V411M mutant. The actual net reduction in current (absolute difference) of lurasidone in the SCN5A p.V411M mutant was 300 pA / pF, far higher than the 133 pA / pF in the WT mutant, suggesting that lurasidone may have stronger functional correction potential in the mutant background. Inhibition with lurasidone can reduce the I-cell irradiation rate of the SCN5A p.V411M mutant HEK293 cells. Na Return to levels comparable to or lower than WT (related to lurasidone concentration).

[0066] Experiment 4: Effect of lurasidone on the gating properties of Nav1.5; HEK293 cells with the SCN5A p.V411M mutation were incubated with 10 μmol / L lurasidone solution for 24 h. Steady-state activation curves (SSA) and steady-state inactivation curves (SSI) were obtained using the double-pulse stimulation method. The results are as follows: Figure 3 and Figure 4 As shown, HEK293 cells with the SCN5A p.V411M mutation (SCN5A p.V411M), HEK293 cells without the SCN5A mutation (WT), and HEK293 cells without the SCN5A mutation that underwent the same lurasidone incubation procedure (WT + lurasidone) were used as controls; The results were obtained using formula G. Na =I Na Calculate the conductance at each voltage using / (Vm-Vrev), I Na The peak values ​​of the whole-cell current are shown at different voltages, Vm is the depolarization pulse voltage, and Vrev is the channel reversal potential. The steady-state activation (SSA) curve of the channel is plotted with the pulse voltage on the horizontal axis and the normalized conductance (G / Gmax) on the vertical axis; the steady-state inactivation (SSI) curve is plotted with the normalized current (I / Imax) on the vertical axis. Both the SSA and SSI curves are fitted using the Boltzmann equation.

[0067] like Figure 3 As shown, the half-activation voltage (V) of the SCN5A p.V411M 1 / 2 The activation voltage (act) shifted by approximately -1.7 mV towards hyperpolarization compared to WT, indicating that the mutation makes the sodium channel readily activated at a lower depolarization voltage, further supporting its "functional enhancement" property. After incubation with 10 μmol / L lurasidone for 24 h, the steady-state activation curve of SCN5A p.V411M shifted significantly to the right towards depolarization, with a half-maximum activation voltage shift of +8.6 mV, suggesting that lurasidone can partially reverse the activation gating abnormality caused by the SCN5A p.V411M mutant and increase the voltage-dependent threshold for sodium channel activation.

[0068] like Figure 4 As shown, unlike its activation properties, SCN5A p.V411M shifts the steady-state inactivation curve toward depolarization. However, after treatment with 10 μmol / L lurasidone, the steady-state inactivation curve of SCN5A p.V411M shifts significantly to the left toward hyperpolarization, with a half-maximum inactivation voltage shift of -17 mV. This indicates that lurasidone enhances the inactivation tendency of sodium channels at the physiological resting potential of mutant cells, restoring them to a steady-state inactivation state close to that of wild-type cells, which is beneficial for inhibiting the abnormally increased inward sodium current.

[0069] The recovery curve (also known as "recovery kinetics" or "reactivation curve") of sodium channels after inactivation primarily characterizes the speed and extent to which the channel recovers from an inactivated state to a resting / closed state where it can be reactivated. Therefore, HEK293 cells with the SCN5A p.V411M mutation were incubated with 10 μmol / L lurasidone solution for 24 h, and the recovery curve of voltage-gated sodium channels after inactivation was obtained using a double-pulse stimulation method. The formula R = I... Na (t) / Imax calculates the current recovery ratio at each recovery time point, where I... Na (t) represents the peak value of whole-cell sodium current induced by the test pulse under different recovery intervals, t is the repolarization recovery interval between the inactivation pre-pulse and the test pulse, and Imax is the maximum peak current induced by the test pulse when the channel is fully recovered. The channel inactivation recovery curve is plotted with the recovery interval duration on the horizontal axis and the normalized current recovery ratio (I / Imax) on the vertical axis. The inactivation recovery curve is fitted using the following single exponential equation: I / Imax = 1 - exp(-t / τ), where I is the peak value of whole-cell sodium current under different recovery intervals, Imax is the maximum peak current when the whole-cell channel is fully recovered, and τ is the recovery time constant after inactivation. The sodium channel current inactivation recovery curve is shown in the figure below. Figure 5 As shown, HEK293 cells with the SCN5A p.V411M mutation (SCN5A p.V411M), HEK293 cells without the SCN5A mutation (WT), and HEK293 cells without the SCN5A mutation that underwent the same lurasidone incubation procedure (WT+lurasidone) were used as controls.

[0070] like Figure 5 As shown, all four recovery curves exhibited a single exponential growth. The recovery time constant τ for WT was 2.05 ± 0.048 ms, and the recovery time constant τ for WT + lurasidone was 1.91 ± 0.032 ms. The channel recovery of SCN5A p.V411M was relatively fast, with a recovery time constant τ of 1.15 ± 0.061 ms. However, after the addition of lurasidone (SCN5A p.V411M + lurasidone), the recovery curve shifted significantly to the right, with τ increasing to 3.31 ± 0.136 ms. This indicates that the recovery rate of the channel from the inactivated state was significantly slowed down, suggesting that lurasidone may exert its inhibitory effect by stabilizing the inactivated state of the channel and prolonging its refractory period.

[0071] Late sodium current characterizes the persistent, minute inward sodium ion flow that occurs when sodium channels fail to completely inactivate during the plateau phase of the action potential (the sustained depolarization phase), and has a decisive impact on the repolarization reserve and electrostability of cardiomyocytes. Therefore, HEK293 cells with the SCN5A p.V411M mutation were incubated with 10 μmol / L lurasidone solution for 24 h, and late sodium current was measured. The stimulation ranged from -140 mV to -20 mV for 700 ms. The sodium current between 50 ms and 150 ms was passively corrected for leakage, and the average current was calculated to obtain the late sodium current. HEK293 cells with the SCN5A p.V411M mutation (SCN5A p.V411M), HEK293 cells without the SCN5A mutation (WT), and HEK293 cells without the SCN5A mutation that underwent the same lurasidone incubation procedure (WT + lurasidone) were used as controls. The late sodium current graph is shown below. Figure 6 As shown.

[0072] like Figure 6 As shown, compared with WT, SCN5A p.V411M significantly increased the late sodium current; under the action of lurasidone, the late sodium current of SCN5A p.V411M was significantly reduced (-8.30±0.77 pA / pF vs. -1.30±0.13 pA / pF), with an inhibition rate of 84.3%. Therefore, lurasidone can eliminate the continuous inward sodium ion flow in the pathological state of LQT3, thereby shortening the prolonged myocardial action potential duration and QT interval, restoring repolarization reserve and eliminating the triggering basis of early afterpolarization (EADs), which provides a clear electrophysiological basis for the treatment of LQT3.

[0073] Experiment 5: Molecular interactions between lurasidone and wild-type and mutant Nav1.5 proteins; Molecular dynamics analysis was performed on SCN5A wild-type (WT), SCN5A p.V411M mutant (SCN5A p.V411M), and SCN5A p.V411M mutant protein system under lurasidone treatment (SCN5A p.V411M+lurasidone).

[0074] Figure 7The plot shows the root mean square deviation (RMSD). The RMSD curve for WT rises rapidly in the early stages of the simulation before plateauing. The average RMSD of the last 10% of the trajectory is 1.025 nm, with an overall mean of 0.915 nm. The RMSD of SCN5A p.V411M increases to 1.206 nm, with an overall mean of 1.025 nm, indicating that the SCN5A p.V411M mutant underwent a more significant overall rearrangement relative to its initial conformation before reaching the plateau. The RMSD of the SCN5A p.V411M + lurasidone system is 1.249 nm, with an overall mean of 1.124 nm, slightly higher than that of SCN5A p.V411M, reflecting further pocket adaptation and local rearrangement of the complex based on its initial docking conformation.

[0075] Figure 8 The RMSF plots for WT show that high-fluctuation regions are mainly located in several loop regions, chain-linked regions, and terminal segments. Typical peak positions are distributed at amino acid positions 36, 208, 299, 690, 802, 872, 1184, 1512, 1614, and near the C-terminus. This distribution conforms to the general characteristic of large protein systems: a relatively stable rigid core and more volatile flexible exposed regions. In the RMSF plot of SCN5A p.V411M, high-fluctuation regions are still mainly located in loop regions and terminal segments, indicating that the mutation did not completely change the approximate spatial location of the flexible regions, but it altered the overall conformational distribution, scale, and sampling path of the protein. The presence of small molecules in the SCN5A p.V411M + lurasidone system causes a slight shift in the high-fluctuation regions of the mutated system.

[0076] Figure 9 The radius of gyration (Rg) curves for WT show an average Rg value of 3.817 nm over the last 10%; the average Rg value for SCN5Ap.V411M over the last 10% is 3.658 nm, which is lower than that of WT; the average Rg value for the SCN5Ap.V411M + lurasidone system over the last 10% is 3.691 nm, which is between the two and is closer to the wild type than the pure mutant. Figure 10 The solvent accessible surface area (SASA) plot for WT shows that the average value of the last 10% of the SASA is 706.2 nm. 2 The average value of SCN5A p.V411M after 10% SASA was 672.8 nm. 2 The average value of SASA in the SCN5A p.V411M + lurasidone system after 10% was 690 nm, lower than WT. 2It falls between the two, being closer to the wild type than the pure mutant. These results indicate that the binding of the small molecule lurasidone did not exacerbate the abnormal collapse of the mutant; instead, it promoted a regression of the overall scale and surface exposure towards the wild type.

[0077] Figure 11 For WT's free energy landscape image, Figure 12 Free energy landscape diagram of SCN5A p.V411M Figure 13 The free energy landscape diagrams for the SCN5Ap.V411M+lurasidone system are shown. The free energy landscape diagram of WT shows a relatively concentrated and well-defined lowest free energy basin, indicating that the system formed a relatively clear set of dominant conformations within 100 ns of simulation. The free energy landscape diagram of SCN5Ap.V411M shows that its low-energy region is longer than that of WT, suggesting that the mutation expands the conformational sampling range and reduces the concentration of dominant conformations. The free energy landscape diagram of the SCN5Ap.V411M+lurasidone system shows that its free energy landscape exhibits a single main basin structure with extended low-energy paths, indicating that the system retains conformational rearrangement capabilities while maintaining stable binding.

[0078] Therefore, the SCN5A p.V411M+lurasidone system tends to be stable after binding-induced adaptation, and its overall conformational characteristics partially revert to the wild-type kinetic state.

[0079] Figure 14 The results show molecular docking. In the figure, green represents lurasidone, and cyan represents SCN5A p.V411M protein (PDB database ID: 8VYJ). Figure 15 This is a diagram of residue energy decomposition. Figure 16 The diagram shows the energy composition, where VDWAALS is the van der Waals energy, EEL is the gas-phase electrostatic energy, GGAS is the total gas-phase energy, EPB is the polar solvation energy, ENPOLAR is the nonpolar solvation energy, GSOLV is the total solvation free energy, and TOTAL is the total binding free energy.

[0080] The lurasidone small molecule is located within a hydrophobic pocket inside the SCN5A p.V411M protein, surrounded by residues such as ASN406, ALA410, ALA413, PHE934, LEU938, LEU1462, ILE1466, ILE1470, ILE1771, and LEU1772. The protein-small molecule hydrogen bonds in the SCN5A p.V411M+lurasidone system are predominantly transient, and stability is mainly attributed to hydrophobic matching, van der Waals contacts, and pocket-filling effects, consistent with the results of the Poisson-Boltzmann surface area method (MM-PBSA). Lurasidone may regulate its binding by occupying a hydrophobic pocket adjacent to the mutant, optimizing local stacking, and mitigating mutation-induced aberrant contraction, rather than simply relying on a long-lived hydrogen bond network. This binding mode provides a reasonable structural explanation for the SCN5A p.V411M+lurasidone system's overall geometric indices being closer to the wild type than the pure mutant system.

[0081] The total binding free energy of the SCN5A p.V411M+ lurasidone system is -296.65 kJ / mol, indicating that lurasidone can form a significantly favorable binding in the mutant protein pocket. Binding energy component analysis shows that the van der Waals term (VDWAALS, -247.65 kJ / mol) is the most significant contributor to the favorable binding, the electrostatic term (EEL, -42.63 kJ / mol) provides a secondary favorable effect, and the polar solvation term (EPB, 169.79 kJ / mol) cancels out the binding, indicating that lurasidone requires a certain desolvation cost to enter the binding pocket. Overall, this system exhibits typical hydrophobic / van der Waals-dominated binding energy characteristics with partial cancellation by polar solvation. Residue decomposition further revealed binding hotspots at LEU938, ILE1466, LEU409, ILE1470, MET414, LEU1772, LEU1462, ILE1768, and ILE1771, with LEU938 and ILE1466 making the most significant contributions. Most of these residues are hydrophobic amino acids, primarily distributed in four local regions (intracellular fragments of the S6 transmembrane segment of the homology domain) at 409-414, 934-938, 1462-1470, and 1768-1775, suggesting that the small molecule achieves stable binding through multi-point hydrophobic embedding and pocket filling. Particularly noteworthy is the proximity of the 409-414 region to the mutation site V411M, indicating that the stable binding of lurasidone is directly related to the local microenvironment of the mutation, supporting the possibility of its ability to regulate the conformation of the mutant from a molecular binding perspective.

[0082] Hydrogen bond analysis reveals that lurasidone's mechanism of action does not rely on a few persistent strong hydrogen bonds to lock the protein into a rigid conformation. Instead, it improves local pocket stacking, compensates for changes in the hydrophobic environment surrounding the mutation, and weakens the aberrant collapse tendency, allowing the system to maintain a conformational distribution closer to the wild type within a lower free energy region. The binding free energy of the V411M+lurasidone system is mainly driven by van der Waals interactions and nonpolar interactions; key contributing residues are concentrated in the amino acid sequences around 409-414, 934-938, 1462-1470, and 1768-1775. The RMSD of the SCN5A p.V411M and WT protein structures after stabilization is 7.724 Å, while the RMSD of the SCN5A p.V411M+lurasidone system after stabilization is 6.601 Å.

[0083] Based on comprehensive stability indices, binding energy decomposition, binding site characteristics, and structural superposition results, it is demonstrated that the introduction of lurasidone makes the V411M mutant closer to the wild-type state at the conformational dynamics level.

[0084] In summary, the above results demonstrate that lurasidone is a potent direct inhibitor of the open Nav1.5 channel, with an IC50 value of 7.05 μmol / L. Simultaneously, the Nav1.5 current is strongly blocked by lurasidone in a concentration-dependent manner. Lurasidone can partially reverse the activation gating abnormality induced by V411M. Lurasidone enhances the inactivation tendency of the Nav1.5 channel and slows its recovery. Lurasidone has an inhibitory efficiency of 84.3% on the late sodium current in mutant cells, and can almost restore the abnormal increase in late sodium current caused by mutation to normal physiological levels. Lurasidone is a Nav1.5 channel inhibitor that can be used in humans. At a concentration of 10 μmol / L, lurasidone showed an inhibitory efficiency of 72.6% ± 4.4% on the peak current of the Nav1.5 channel, significantly higher than other Nav1.5 channel inhibitors reported in previous studies. At a concentration of 300 μmol / L hesperetin, the Nav1.5 current amplitude was reduced by a maximum of 49.25% (Wang H, Wang HF, Zhang H, Wang C, Chen YF, Ma R, Xiang JZ, Du XL, Tang Q. Inhibitory effects of hesperetin on Nav1.5 channels stably expressed in HEK 293 cells and on the voltage-gated cardiac sodium current in human atrialmyocytes. Acta Pharmacol Sin. 2016 Dec;37(12):1563-1573. doi: 10.1038 / aps.2016.97), Tramadol at a concentration of 1000 μmol / L reduced the Nav1.5 current amplitude by 69% ± 3.7% (Jia L, Veldkamp MW, Verkerk AO, Tan HL. The opioid tramadol blocks the cardiacsodium channel Nav1.5 in HEK293 cells. Europace. 2023 Aug 2;25(9):euad209.doi: 10.1093 / europace / euad209. PMID: 37433113; PMCID: PMC10396326).

[0085] Molecular docking and all-atom molecular dynamics simulations indicate that lurasidone may promote the conformational correction of the pathological protein caused by the SCN5A gene mutation (p.V411M) by directly binding to the Nav1.5 channel, thereby restoring the channel's normal gating properties and inhibiting the abnormally increased sodium current. The small lurasidone molecule stably binds to a hydrophobic pocket within the Nav1.5 channel protein, surrounded by key residues including ASN406, ALA410, ALA413, PHE934, LEU938, LEU1462, ILE1466, ILE1470, ILE1771, and LEU1772. This binding pattern exhibits a distinct hotspot aggregation characteristic, mainly distributed in four local peptide segments: 409-414, 934-938, 1462-1470, and 1768-1775. These regions are all located on the intracellular lateral surface of the S6 transmembrane segment of each homologous domain, constituting a typical hydrophobic ligand binding microenvironment. Lurasidone achieves stable binding through multi-site hydrophobic embedding and pocket-filling effects, thereby bringing the V411M mutant closer to the wild-type channel state at the conformational dynamics level. Further analysis shows that lurasidone occupies the inherent hydrophobic pocket adjacent to the mutation site, optimizing the spatial stacking of local amino acid residues, thus alleviating the abnormally tight local channel structure induced by the V411M mutation. This conformational correction effect ultimately manifests as the restoration of the voltage-dependent gating properties of the Nav1.5 channel and the effective suppression of current intensity.

[0086] In summary, lurasidone and its pharmaceutically acceptable salts can be used as drugs to treat type 3 long QT syndrome and as Nav1.5 inhibitors to suppress abnormally increased late sodium currents, shorten prolonged myocardial action potential duration and QT interval, thus providing a new approach to the treatment of type 3 long QT syndrome.

[0087] The above description represents the preferred embodiments of this application, but should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

Claims

1. The use of lurasidone or a pharmaceutically acceptable salt thereof in the preparation of medicaments for the treatment of type 3 long QT syndrome.

2. The application as described in claim 1, characterized in that, Lurasidone or a pharmaceutically acceptable salt thereof treats type 3 long QT syndrome by inhibiting abnormally increased late sodium currents, thereby shortening the prolonged myocardial action potential duration and QT interval.

3. The application as described in claim 1 or 2, characterized in that, The lurasidone or a pharmaceutically acceptable salt thereof binds to Nav1.5, promoting conformational correction of the SCN5A mutant protein, inhibiting abnormally increased late sodium current, and treating type 3 long QT syndrome.

4. The application as described in claim 1, characterized in that, The lurasidone or a pharmaceutically acceptable salt thereof constitutes the medicament for treating type 3 long QT syndrome, either as a single active ingredient or with other pharmaceutically acceptable active ingredients.

5. The application as described in claim 1, characterized in that, The mass content of lurasidone or a pharmaceutically acceptable salt thereof in the drug for treating type 3 long QT syndrome is 0.01%-100%.

6. The application as described in claim 1, characterized in that, The medication for treating type 3 long QT syndrome also includes pharmaceutically acceptable excipients; The excipients include at least one of the following: diluent, solubilizer, binder, disintegrant, lubricant, wetting agent, flavoring agent, emulsifier, antioxidant, preservative, and pH adjuster.

7. The application as described in claim 1, characterized in that, The form of the medicine for treating type 3 long QT syndrome includes at least one of the following: injection, tablet, granule, capsule, oral liquid, and pill.

8. The application as described in claim 1, characterized in that, The medication for treating type 3 long QT syndrome is administered orally or by injection.

9. Use of lurasidone or a pharmaceutically acceptable salt thereof in the preparation of Nav1.5 inhibitors.

10. A drug, characterized in that, This includes lurasidone or a pharmaceutically acceptable salt thereof, the drug being used to treat type 3 long QT syndrome or the drug being a Nav1.5 inhibitor.

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