Effect of Neuroligin1 and Neurexin1 on the Colonic Motility in a Mouse Model of Neuronal Intestinal Dysplasia

Cerebral Hypoxia-Induced Molecular Alterations and Their Impact on the Physiology of Neurons and Dendritic Spines: A Comprehensive Review

This article comprehensively reviews how cerebral hypoxia impacts the physiological state of neurons and dendritic spines through a series of molecular changes, and explores the causal relationship between these changes and neuronal functional impairment. As a severe pathological condition, cerebral hypoxia can significantly alter the morphology and function of neurons and dendritic spines. Specifically, dendritic spines, being the critical structures for neurons to receive information, undergo changes such as a reduction in number and morphological abnormalities under hypoxic conditions. These alterations further affect synaptic function, leading to neurotransmission disorders. This article delves into the roles of molecular pathways like MAPK, AMPA receptors, NMDA receptors, and BDNF in the hypoxia-induced changes in neurons and dendritic spines, and outlines current treatment strategies. Neurons are particularly sensitive to cerebral hypoxia, with their apical dendrites being vulnerable to damage, thereby affecting cognitive function. Additionally, astrocytes and microglia play an indispensable role in protecting neuronal and synaptic structures, regulating their normal functions, and contributing to the repair process following injury. These studies not only contribute to understanding the pathogenesis of related neurological diseases but also provide important insights for developing novel therapeutic strategies. Future research should further focus on the dynamic changes in neurons and dendritic spines under hypoxic conditions and their intrinsic connections with cognitive function.

A novel mouse model of intestinal neuronal dysplasia: visualization of the enteric nervous system

PURPOSE

Intestinal neuronal dysplasia (IND) is a congenital anomaly affecting gastrointestinal neural innervation, but the pathogenesis remains unclear. The homozygous Ncx/Hox11L.1 knockout (Ncx-/-) mice exhibit megacolon and enteric ganglia anomalies, resembling IND phenotypes. Sox10-Venus transgenic mouse were used to visualize enteric neural crest cells in real time. This study aims to establish a novel mouse model of Sox10-Venus+/Ncx-/- mouse to study the pathogenesis of IND.

METHODS

Sox10-Venus+/Ncx-/- (Ncx-/-) (n = 8) mice and Sox10-Venus+/Ncx+/+ controls (control) (n = 8) were euthanized at 4-5 weeks old, and excised intestines were examined with fluorescence microscopy. Immunohistochemistry was performed on tissue sections with neural marker Tuj1.

RESULTS

Ncx-/- mice exhibited dilated cecum and small intestine. Body weight of Ncx-/- mice was lower with higher ratio of small intestine length relative to body weight. The neural network (Sox10-Venus) was observed along the intestine wall in Ncx-/- and control mice without staining. Ectopic and increased expression of Tuj1 was observed in both small intestine and proximal colon of Ncx-/- mice.

CONCLUSION

This study has established a reliable animal model that exhibits characteristics similar to patients with IND. This novel mouse model can allow the easy visualization of ENS in a time- and cost-effective way to study the pathogenesis of IND.

Intestinal neuronal dysplasia presenting as psoas abscess: A case report

Background

Intestinal neuronal dysplasia (IND) is a rare condition mainly affecting the children. Constipation and abdominal distension have been reported as common manifestations. In addition, the reports about adult cases are scarce.

Case report

A 31-year-old man presented with pain in his left hip and intermittent fever for 1 month. The whole abdomen CT and pelvic contrast-enhanced MRI revealed a left psoas abscess (PA). The patient has been given anti-infective treatment and underwent CT-guided drainage of left PA with a temporary drain. But the patient's condition did not improve significantly. Then, the colonoscopy revealed that it may be the PA secondary to inflammatory bowel disease. But the pathology was not in line with inflammatory bowel disease. We finally performed an ileostomy surgery and took the whole layer of intestinal wall for biopsy. The pathological result revealed that a large number of proliferative ganglion cells and circuitous hyperplastic nerve fibers were found in the submucosa and muscular layer of the intestinal wall. Given pathological results and clinical manifestations, the patient was diagnosed with IND-B.

Conclusion

In this case, we first report an extremely rare case of adult IND manifesting as PA. So, this unusual case provides a new supplement to adult cases of IND.

LMWP (S3-3) from the Larvae of Musca domestica Alleviate D-IBS by Adjusting the Gut Microbiota

Diarrhea-based Irritable Bowel Syndrome (D-IBS) and diarrhea are both associated with ecological imbalance of the gut microbiota. Low Molecular Weight Peptides (LMWP) from the larvae of Musca domestica have been shown to be effective in the treatment of diarrhea and regulation of gut microbiota. Meanwhile, the single polypeptide S3-3 was successfully isolated and identified from LMWP in our previous studies. It remains unclear exactly whether and how LMWP (S3-3) alleviate D-IBS through regulating gut microbiota. We evaluated the gut microbiota and pharmacology to determine the regulation of gut microbiota structure and the alleviating effect on D-IBS through LMWP (S3-3). The rates of loose stools, abdominal withdrawal reflex (AWR) and intestinal tract motility results revealed that LMWP (S3-3) from the larvae of Musca domestica had a regulating effect against diarrhea, visceral hypersensitivity and gastrointestinal (GI) dysfunction in D-IBS model mice. Additionally, 16S rRNA gene sequencing was utilized to examine the gut microbiota, which suggests that LMWP induce structural changes in the gut microbiota and alter the levels of the following gut microbiota: Bacteroidetes, Proteobacteria and Verrucomicrobia. LMWP putatively functioned through regulating 5-HT, SERT, 5-HT2AR, 5-HT3AR and 5-HT4R according to the results of ELISA, qRT-PCR and IHC. The findings of this study will contribute to further understanding how LMWP (S3-3) attenuate the effects of D-IBS on diarrhea, visceral hypersensitivity and GI dysfunction.

Role of GDNF, GFRα1 and GFAP in a Bifidobacterium-Intervention Induced Mouse Model of Intestinal Neuronal Dysplasia

OBJECTIVE

To investigate the effects of glial cell-derived neurotrophic factor (GDNF), GDNF family receptor alpha 1 (GFRα1), and glial fibrillary acidic protein (GFAP) on colonic motility in a mouse model of intestinal neuronal dysplasia by intervention with Bifidobacterium and to explore the influence of Bifidobacterium on enteric glial cells (EGCs).

METHODS

Western blotting and qRT-PCR were employed to detect the expression of GFRα1 and GFAP in colonic tissues of mice with or without Tlx2 mutations, and ELISA was used to detect the expression of GDNF in serum. IHC was used to detect the appearance of the ganglion cells. Subsequently, Tlx2 homozygous mutant (Tlx2-/-) mice were treated with Bifidobacterium. Colonic motility was measured before and after intervention by measuring the glass bead expelling time. The variations in abdominal circumference and GDNF, GFRα1, and GFAP expression were measured. In addition, 16SrRNA gene sequencing was performed to detect the abundance of the intestinal microbiota.

RESULTS

The mRNA and protein expression of GFRα1 and GFAP was decreased in the colonic tissues of Tlx2-/- mice and GDNF expression was decreased in serum compared with Tlx2+/- and WT mice. After confirming the colonization of Bifidobacterium by 16S rRNA gene sequencing, the expelling time and abdominal distension were ameliorated, and the expression of GFAP, GDNF, and GFRα1 was increased.

CONCLUSIONS

The expression of GDNF, GFRα1, and GFAP is associated with colonic motility. The altered expression of EGC-related factors suggested that Bifidobacterium may be involved in the EGC activation process. The amelioration of IND symptoms after intervention with Bifidobacterium prompted the elicitation of adjuvant therapy.