Use of a gpr120 antagonist to prevent and treat low dose cadmium exposure exacerbated enteritis

Abstract

The application relates to the field of biological medicines, and particularly relates to application of a GPR120 antagonist in preparation of a medicine for preventing and treating low-dose cadmium exposure aggravated enteritis. The application discloses a new function of GPR120, i.e. mediation of low-dose cadmium exposure aggravated intestinal inflammatory injury and barrier damage, and targeted blocking of the function of GPR120 can effectively block the worsening process of enteritis caused by cadmium, repair intestinal injury, and improve intestinal function, thereby providing a novel target and treatment scheme for clinical prevention and treatment of environmental heavy metal exposure related enteritis.

Description

Technical Field

[0001] This invention relates to the field of biomedical technology. Specifically, it relates to a molecular GPR120 that prevents and treats low-dose cadmium exposure-induced enteritis by regulating intestinal inflammatory factors, intestinal barrier, and intestinal cell death patterns, thereby improving the effects, mechanism of action, implementation method, and uses of cadmium-induced enteritis damage. Background Technology

[0002] Cadmium (Cd) is a toxic heavy metal widely found in the natural environment, characterized by extremely low metabolic rate, strong bioaccumulation, and a long biological half-life. Long-term low-dose exposure to cadmium can occur through various pathways, including accumulation in farmland soil-food chains, ingestion through drinking water, and atmospheric deposition. Epidemiological surveys and environmental toxicology studies have confirmed widespread low-dose cadmium exposure in the general population in most parts of the world. Unlike acute high-dose cadmium poisoning, which is currently rare in clinical practice, long-term low-dose cadmium exposure often lacks typical specific signs of poisoning and is easily overlooked clinically. However, it can accumulate continuously in multiple organs, including the intestines, kidneys, and liver, inducing chronic organic damage. Multiple studies have confirmed that the intestines are the primary target organ for cadmium toxicity; compared to secondary liver and kidney damage, the intestines respond earliest to cadmium toxic stimuli. Long-term, low-dose cadmium intervention can significantly disrupt the intestinal microecological structure, affect intestinal flora metabolism, damage the integrity of the intestinal epithelial barrier, and disrupt the local immune homeostasis of the intestine, ultimately inducing and aggravating chronic inflammatory lesions of the intestine. It is one of the core causes of the high incidence and persistent nature of environmental chronic enteritis.

[0003] Inflammatory bowel disease (IBD) mainly includes Crohn's disease and ulcerative colitis. Its core pathological feature is persistent, recurrent chronic inflammation of the intestinal mucosa, characterized by intestinal congestion and edema, mucosal erosion, and widespread infiltration of inflammatory cells. Clinically, it is accompanied by symptoms such as abdominal pain, recurrent diarrhea, weight loss, and rectal bleeding. The disease is protracted and difficult to cure, with a high relapse rate. Long-term illness can induce intestinal fibrosis, intestinal perforation, and even colorectal cancer, severely impairing patients' quality of life. Current clinical research confirms that, in addition to classic pathogenic factors such as genetics, immune disorders, and dietary imbalances, environmental heavy metal exposure is a key independent risk factor mediating the exacerbation of chronic enteritis and the development of refractory enteritis. Specifically, low-dose cadmium exposure can significantly exacerbate chronic intestinal inflammation by regulating intestinal inflammatory responses and barrier function through multiple pathways, promoting the progression of ordinary enteritis to severe, recurrent inflammatory bowel disease, and significantly increasing the risk of poor intestinal prognosis, posing a significant challenge to public health prevention and control as well as clinical treatment.

[0004] Low-dose cadmium exposure can disrupt intestinal homeostasis through multiple pathways, including gut microbiota dysbiosis, intestinal barrier damage, and immune imbalance, resulting in a cascade of toxic effects. First, low-dose cadmium significantly remodels the structure and metabolic function of the gut microbiota, altering its abundance and proportion. A key characteristic is a significantly increased Bacteroidetes / Firmicutes ratio, while simultaneously inhibiting the proliferation of beneficial bacteria such as Lactobacillus and Bifidobacterium, reducing gut microbiota diversity. This dysbiosis directly enhances the metabolic activity of Gram-negative bacteria in the gut, leading to the massive synthesis and release of lipopolysaccharide (LPS). This toxic response occurs rapidly in the early stages of cadmium exposure and persists long after exposure. Second, cadmium can directly damage the intestinal epithelial structure, significantly downregulating the expression and disrupting the normal distribution of tight junction proteins Occludin, Claudin-1, and ZO-1, causing breakage of intestinal tight junction structures and abnormally increased intestinal permeability, resulting in a typical "leaky gut" phenotype. Intestinal barrier damage coupled with dysbiosis-mediated excessive LPS production leads to a significant increase in LPS entry into the bloodstream, causing local and systemic endotoxemia. Simultaneously, it induces intestinal bacterial translocation, further amplifying the body's infection risk and inflammatory damage. Furthermore, LPS invading intestinal tissues and the circulatory system can specifically activate the classical TLR4 / NF-κB inflammatory pathway, inducing massive activation of intestinal macrophages and lymphocytes. This continuously promotes the explosive release of pro-inflammatory factors such as TNF-α, IL-1β, IL-6, and IL-17, while inhibiting the secretion of anti-inflammatory factors such as IL-10, completely disrupting the intestinal pro-inflammatory / anti-inflammatory immune balance. In addition, low-dose cadmium can significantly induce excessive ROS accumulation in intestinal cells, triggering oxidative stress damage and intestinal epithelial cell apoptosis, further exacerbating intestinal barrier damage and dysbiosis, forming a vicious cycle of "dysbiosis-endotoxin release-barrier damage-inflammatory activation," continuously driving ordinary chronic enteritis towards severe, refractory inflammatory bowel disease.

[0005] G protein-coupled receptor 120 (GPR120), also known as free fatty acid receptor 4 (FFAR4), is a transmembrane receptor widely expressed on the surface of intestinal epithelial cells, intestinal macrophages, CD4+ T cells, and enteroendocrine L cells. It can specifically recognize long-chain unsaturated fatty acids such as ω-3 and ω-6 and is a key target for regulating intestinal immune homeostasis, inflammatory response, and barrier function. It plays a core regulatory role in the occurrence and development of inflammatory bowel disease. Existing research confirms that GPR120 exhibits significant cell specificity and bidirectional regulation. Its normal activation can mediate intestinal anti-inflammatory protective effects: In intestinal epithelial cells, GPR120 activation can inhibit TAK1 activation through the β-arrestin2 / TAB1 signaling complex, thereby blocking the NF-κB inflammatory pathway, reducing the release of pro-inflammatory factors, and upregulating mucin expression to maintain intestinal barrier integrity; In CD4+ T cells, GPR120 can promote the secretion of the anti-inflammatory factor IL-10 through the mTOR / Stat3-Blimp1 pathway, inhibiting Th1 / Th17 cell-mediated pro-inflammatory immune responses; In macrophages, GPR120 activation can inhibit the infiltration of M1 pro-inflammatory macrophages and promote the polarization of M2 anti-inflammatory macrophages, effectively alleviating intestinal inflammatory damage.

[0006] AH7614 is a highly specific and selective small-molecule GPR120 antagonist that precisely targets and binds to the GPR120 receptor protein, specifically blocking the abnormal activation of GPR120 and the disordered downstream signaling pathways under pathological conditions. It also possesses advantages such as small molecular weight, good biocompatibility, high efficacy in intestinal tissue, and no significant cytotoxicity. Compared to existing non-specific anti-inflammatory drugs, AH7614 can block the cadmium-mediated abnormal pro-inflammatory pathway of GPR120 at its source, reversing the vicious cycle of intestinal immune dysregulation and barrier damage, and precisely targeting the treatment of enteritis exacerbated by low-dose cadmium exposure. Currently, there are no research or patent reports on the application of GPR120 antagonists in the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure, nor are there any related targeted treatment regimens.

[0007] In summary, existing research has clearly demonstrated that low-dose cadmium exposure can persistently exacerbate chronic intestinal inflammation through a multi-tiered cascade mechanism, including disrupting the gut microbiota, damaging the intestinal barrier integrity, disrupting intestinal immune balance, and inducing oxidative stress damage. It is a significant environmental factor contributing to clinically refractory and recurrent inflammatory bowel disease. Currently reported interventions for cadmium-induced intestinal toxicity and exacerbated colitis mainly include conventional approaches such as metal chelating agent detoxification, broad-spectrum antioxidant therapy, non-specific anti-inflammatory drug intervention, and probiotic intestinal conditioning.

[0008] However, existing technologies have significant limitations and gaps: First, traditional metal chelators only focus on the removal of heavy metals from the body and cannot specifically improve the intestinal flora imbalance, intestinal barrier damage, and persistent chronic inflammation caused by cadmium exposure, nor do they treat existing enteritis lesions; Second, clinical broad-spectrum anti-inflammatory drugs can only non-specifically inhibit the release of inflammatory factors and cannot block the cadmium-mediated vicious cycle of "flora flora imbalance - abnormal metabolites - increased inflammation," treating the symptoms but not the root cause. Inflammation is prone to relapse after drug withdrawal, and long-term use also has side effects such as intestinal flora imbalance and liver and kidney toxicity; Third, probiotics, antioxidants, and other auxiliary interventions have broad targets but limited intervention efficacy; Fourth, existing publicly available technologies and research have not revealed the abnormal pro-inflammatory function of GPR120 receptors in the microenvironment of heavy metal cadmium exposure, nor have they proposed a technical approach to prevent and treat enteritis exacerbated by low-dose cadmium exposure by targeting and antagonizing GPR120. There are currently no targeted drugs or patented solutions that can achieve precise intervention for this pathological pathway. Summary of the Invention

[0009] The purpose of this invention is to explore the key molecular targets for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure and the potential clinical translational applications and effective use pathways of their small molecule antagonists, and to provide the function, implementation method and use of a GPR120 antagonist for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure.

[0010] Based on previous mechanistic studies, this invention confirms that GPR120 is a key target mediating the exacerbation of enteritis by low-dose cadmium exposure through increased production of the gut microbiota metabolite oleic acid. Its abnormal pathological activation is a core molecular factor distinguishing it from ordinary enteritis and contributing to the refractory and recurrent nature of cadmium-induced enteritis. Compared to existing non-specific treatments, this invention utilizes GPR120 antagonists to target and block the abnormal GPR120 signaling pathway under pathological conditions. This allows for simultaneous upstream regulation of intestinal inflammatory responses, barrier homeostasis, oxidative stress, and gut microbiota dysbiosis, overcoming the technical bottleneck of traditional treatments that rely on single targets and have limited efficacy. Therefore, developing drug applications and intervention programs centered on GPR120 antagonists can fill the gap in the field of precise targeted therapy for refractory heavy metal-induced enteritis, providing a novel, efficient, and specific technical approach for the clinical prevention and treatment of enteritis exacerbated by low-dose cadmium exposure. This approach possesses significant clinical application value, industrial transformation prospects, and public health control significance.

[0011] A first aspect of the invention provides the use of a GPR120 antagonist in the preparation of a medicament for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure.

[0012] Furthermore, the aforementioned GPR120 antagonists refer to a class of chemical molecules or drug compounds capable of specifically binding to and inhibiting the activity of G protein-coupled receptor 120 (GPR120, also known as FFA4). Their core function is to block the binding of endogenous fatty acids (such as ω-3 and ω-6 polyunsaturated fatty acids) or synthetic agonists to this receptor, thereby shutting down the GPR120-mediated downstream signaling pathway.

[0013] In one embodiment of the present invention, the GPR120 antagonist is the small molecule antagonist AH7614.

[0014] Furthermore, in the aforementioned applications, the GPR120 antagonist is used in the preparation of drugs that inhibit low-dose cadmium exposure-mediated intestinal inflammation, reduce the level of pro-inflammatory factors in the intestine, and alleviate inflammatory infiltration of intestinal tissue.

[0015] Furthermore, in the aforementioned applications, GPR120 antagonists are used in the preparation of drugs that repair intestinal epithelial barrier damage, upregulate tight junction protein expression, reduce the disease activity index of intestinal inflammation, block the aggravating effect of low-dose cadmium exposure on enteritis, and improve intestinal pathological damage.

[0016] In a second aspect, the present invention provides a medicament for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure, wherein the active ingredient in the medicament is a GPR120 antagonist.

[0017] Furthermore, the medicament for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure also includes other pharmaceutically acceptable ingredients.

[0018] Furthermore, the other pharmaceutically acceptable components are agents that inhibit the expression and function of GPR120, or one or more pharmaceutically permissible carriers or excipients.

[0019] The advantages of this invention are:

[0020] 1. This invention reveals for the first time the novel use of GPR120 protein and its small molecule antagonist AH7614 in regulating the pathological process of enteritis exacerbated by low-dose cadmium exposure. By targeting the function of GPR120 protein in intestinal tissue, it is possible to effectively block the deterioration of intestinal inflammation mediated by low-dose cadmium, thereby achieving effective prevention and treatment of cadmium-exacerbated enteritis.

[0021] 2. This invention, through computational biology and extensive animal model experiments, discovered that GPR120 is the membrane protein most relevant to oleic acid binding and signal transduction among the common membrane receptor targets of cadmium, oleic acid, and inflammatory bowel disease. Targeted intervention of GPR120 expression and function in intestinal tissue can effectively inhibit cadmium-induced intestinal inflammation, repair intestinal barrier damage, alleviate intestinal pathological lesions, and improve enteritis symptoms. Based on this, this invention was completed.

[0022] Specifically, targeted molecular intervention for heavy metal exposure-mediated chronic enteritis is a hot topic in biomedical research. By targeting and inhibiting GPR120 function, the aggravation of intestinal inflammation caused by low-dose cadmium exposure can be blocked, providing a new technical approach for the prevention and treatment of environmental heavy metal-related intestinal diseases. It has broad application prospects in the fields of clinical drug development and treatment of intestinal diseases caused by heavy metal poisoning.

[0023] This invention reveals that GPR120 in intestinal tissue plays a core regulatory role in the pathological process of enteritis exacerbated by low-dose cadmium exposure. Intraperitoneal injection of the GPR120 small molecule antagonist AH7614 significantly improved enteritis symptoms in mice exposed to low doses of cadmium, reduced the release of pro-inflammatory factors, upregulated tight junction protein expression, and alleviated inflammatory infiltration in intestinal tissue. These findings suggest that GPR120 has the potential to prevent and treat enteritis exacerbated by low-dose cadmium exposure by regulating intestinal inflammatory immunity and barrier homeostasis. Therefore, this invention provides methods and strategies for applying GPR120 molecules and its small molecule antagonists to the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure, and explores its effective application pathways.

[0024] 3. This invention reveals a novel function of GPR120, namely, mediating the exacerbation of intestinal inflammation and barrier damage caused by low-dose cadmium exposure. Targeting and blocking the function of GPR120 can effectively block the progression of cadmium-induced enteritis, repair intestinal damage, and improve intestinal function, providing a new target and treatment plan for the clinical prevention and treatment of environmental heavy metal exposure-related enteritis. Attached Figure Description

[0025] Figure 1 GPR120 antagonist AH7614 alleviated the pathological damage of enteritis in mice exposed to low doses of cadmium. a) HE staining pathological morphological changes in intestinal tissue of mice in each group; b) intestinal weight-to-length ratio of each group; c) Disease activity index (DAI) score of mice in each group.

[0026] Figure 2 The GPR120 antagonist AH7614 inhibited the intestinal inflammatory response mediated by low-dose cadmium exposure. The figure shows the mRNA expression levels of pro-inflammatory factors TNF-α, IL-1β, and IL-6 in the intestinal tissue of mice in each group.

[0027] Figure 3 The GPR120 antagonist AH7614 repaired intestinal barrier damage induced by low-dose cadmium exposure. The figure shows the protein expression changes of the intestinal tight junction proteins Occludin, Claudin-1, and ZO-1 in mice of different groups. Detailed Implementation

[0028] The specific implementation methods provided by the present invention will be described in detail below with reference to the embodiments.

[0029] Example 1: GPR120 antagonist AH7614 alleviates enteritis pathological damage in mice exposed to low doses of cadmium.

[0030] Six- to eight-week-old C57BL / 6J wild-type mice were selected and divided into four groups: a blank control group (normal drinking water), an enteritis group (2% DSS drinking water), a cadmium-exposed enteritis model group (100 nM CdCl2 + 2% DSS drinking water), an AH7614-intervention enteritis group (AH7614, 2% DSS drinking water), and an AH7614-intervention cadmium-exposed enteritis model group (AH7614, 100 nM CdCl2 + 2% DSS drinking water). A mouse model of low-dose cadmium exposure-induced enteritis was established by allowing free access to a low-dose cadmium solution (100 nM CdCl2) for 8 consecutive weeks, followed by induction with 2% sodium dextran sulfate (DSS) in the drinking water. Mice were observed for 7 consecutive days. The blank control group mice were fed normal drinking water without cadmium exposure or DSS intervention. The AH7614 intervention involved intraperitoneal injection of sodium dextran sulfate (DSS) into the drinking water 4 days before the initial treatment, followed by injections every 4 days until the end of the experiment. After the experiment, colon tissue was separated for further testing.

[0031] Experimental results showed that compared with the cadmium-exposed enteritis model group, the typical pathological features of enteritis in the colonic tissue of mice in the AH7614 pre-cadmium-exposed enteritis model group were significantly improved, including mucosal congestion, edema, mucosal erosion, and extensive infiltration of inflammatory cells. Figure 1 a) The ratio of intestinal weight to length decreased ( Figure 1 b), Disease Activity Index (DAI) score decreased significantly ( Figure 1 c).

[0032] The results of Example 1 indicate that GPR120 in intestinal tissue plays an important role in the pathological process of exacerbated enteritis by low-dose cadmium exposure.

[0033] Example 2: GPR120 antagonist AH7614 inhibits low-dose cadmium exposure-mediated intestinal inflammatory response.

[0034] The expression levels of intestinal inflammatory factors mRNA were detected by Q-PCR. The results showed that, compared with the enteritis group, the mRNA expression levels of pro-inflammatory factors such as TNFα, IL-1β, and IL-6 in the intestinal tissue of mice in the cadmium-exposed enteritis model group were significantly upregulated. Figure 2 (a, 2b, 2c) The inflammatory response was severe. Compared with the cadmium exposure enteritis model group, the TNF-α mRNA content in the intestinal tissue of mice in the AH7614 intervention cadmium exposure enteritis model group was significantly decreased ( Figure 2 a) The intestinal inflammatory response is selectively blocked.

[0035] The results of Example 2 show that the GPR120 antagonist AH7614 can reduce the release of the intestinal pro-inflammatory factor TNFα, effectively inhibit the intestinal inflammatory response mediated by low-dose cadmium exposure, and alleviate intestinal inflammatory damage.

[0036] Example 3: GPR120 antagonist AH7614 repairs intestinal barrier damage caused by low-dose cadmium exposure.

[0037] The expression levels of intestinal tight junction proteins mRNA were detected by Q-PCR. Results showed that the expression of Ecadherin, ZO-1, and Occludin in the intestinal tissue of mice in the cadmium-exposed enteritis model group was significantly downregulated. Figure 3 a, 3b, 3c), intestinal barrier integrity was disrupted; compared with the cadmium exposure enteritis model group, the expression of Occludin mRNA in the intestinal tissue of mice in the AH7614 intervention cadmium exposure enteritis model group was significantly restored, and the intestinal barrier structure was effectively repaired. Figure 3 c). Furthermore, compared to the enteritis group, the expression of the tight junction protein Occludin mRNA in the intestinal tissue of mice treated with AH7614 was significantly upregulated ( Figure 3 c).

[0038] The results of Example 3 show that the GPR120 antagonist AH7614 can effectively repair intestinal barrier damage caused by low-dose cadmium exposure.

[0039] The above results confirm that the GPR120 small molecule antagonist AH7614 can regulate intestinal inflammatory immunity and barrier homeostasis by specifically antagonizing GPR120, effectively improving enteritis damage aggravated by low-dose cadmium exposure, and has good therapeutic effects and clinical translation potential.

[0040] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. Application of GPR120 antagonists in the preparation of drugs for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure.

2. The use of the GPR120 antagonist according to claim 1 in the preparation of a medicament for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure, characterized in that, The GPR120 antagonist refers to a chemical molecule or drug compound that can specifically bind to and inhibit the activity of GPR120.

3. The use of the GPR120 antagonist according to claim 2 in the preparation of a medicament for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure, characterized in that, The GPR120 antagonist mentioned above is the small molecule antagonist AH7614.

4. The use of the GPR120 antagonist according to claim 1 in the preparation of a medicament for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure, characterized in that, Application of GPR120 antagonists in the preparation of drugs that inhibit low-dose cadmium exposure-mediated intestinal inflammation, reduce the level of pro-inflammatory factors in the intestine, and alleviate inflammatory infiltration of intestinal tissue.

5. The use of the GPR120 antagonist according to claim 1 in the preparation of a medicament for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure, characterized in that, Application of GPR120 antagonists in the preparation of drugs that repair intestinal epithelial barrier damage, upregulate tight junction protein expression, reduce the disease activity index of intestinal inflammation, block the aggravating effect of low-dose cadmium exposure on enteritis, and improve intestinal pathological damage.

6. A medicament for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure, characterized in that, The active ingredient in the drug is a GPR120 antagonist.

7. The medicament for preventing and treating enteritis exacerbated by low-dose cadmium exposure according to claim 6, characterized in that, The medicine described for the prevention and treatment of enteritis exacerbated by low-dose cadmium exposure also includes other pharmaceutically acceptable ingredients.

8. The medicament for preventing and treating enteritis exacerbated by low-dose cadmium exposure according to claim 7, characterized in that, Other pharmaceutically acceptable ingredients are reagents that inhibit the expression and function of GPR120, or pharmaceutically permissible carriers or excipients.

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