Rab11FIP1-deficient mice develop spontaneous inflammation and show increased susceptibility to colon damage

Identification and study of mood-related biomarkers and potential molecular mechanisms in type 2 diabetes mellitus

A significant correlation between type 2 diabetes mellitus (T2DM) and mood has been reported. However, the specific mechanism of mood's role in T2DM is unclear. This study aims to discover mood-related biomarkers in T2DM and further elucidate their underlying molecular mechanisms. The GSE81965 and GSE55650 datasets were sourced from public databases, and mood-related genes (MRGs) were retrieved from previous literature. Initially, differentially expressed MRGs (DE-MRGs) were obtained by combining differential expression analysis and weighted gene co-expression network analysis (WGCNA). Subsequently, the DE-MRGs were incorporated into the LASSO and SVM to identify diagnostic biomarkers for T2DM. Four machine learning methods were utilized to construct the diagnostic models in T2DM, and the model with the optimal algorithm was screened. Further, based on biomarkers, functional enrichment, immune infiltration, and regulatory network analyses were conducted to excavate deeper into the pathogenesis of T2DM. In vivo experiments were used to validate the expression of the biomarkers. A total of 23 DE-MRGs were identified by overlapping 723 DEGs and 64 key modules, and there were strong positive correlations between these DE-MRGs. Afterward, KCTD16, SLC8A1, RAB11FIP1, and RASGEF1B were identified as biomarkers associated with mood in T2DM, and they had favorable diagnostic performance. Meanwhile, the RF diagnostic model constructed based on biomarkers was performed optimally and had high diagnostic accuracy for T2DM patients. Animal experiments indicated that expression levels of SLC8A1, RAB11FIP1, and RASGEF1B in T2DM were consistent with the microarray results. In conclusion, KCTD16, SLC8A1, RAB11FIP1, and RASGEF1B were identified as biomarkers related to mood in T2DM.

A Role of Inflammation in Charcot-Marie-Tooth Disorders-In a Perspective of Treatment?

Despite the fact that there are published case reports and model work providing evidence of inflammation in Charcot-Marie-Tooth disorders (CMTs), in clinical practice, CMT and inflammatory neuropathies are always classified as two separate groups of disorders. This sharp separation of chronic neuropathies into two groups has serious clinical implications. As a consequence, the patients harboring CMT mutations are practically excluded from pharmacological anti-inflammatory treatments. In this review, we present that neuropathological studies of peripheral nerves taken from some patients representing familial aggregation of CMTs revealed the presence of inflammation within the nerves. This shows that neurodegeneration resulting from germline mutations and the inflammatory process are not mutually exclusive. We also point to reports demonstrating that, at the clinical level, a positive response to anti-inflammatory therapy was observed in some patients diagnosed with CMTs, confirming the role of the inflammatory component in CMT. We narrowed a group of more than 100 genes whose mutations were found in CMT-affected patients to the seven most common (MPZ, PMP22, GJB1, SEPT9, LITAF, FIG4, and GDAP1) as being linked to the coexistence of hereditary and inflammatory neuropathy. We listed studies of mouse models supporting the idea of the presence of an inflammatory process in some CMTs and studies demonstrating at the cellular level the presence of an inflammatory response. In the following, we discuss the possible molecular basis of some neuropathies involving neurodegenerative and inflammatory processes at both the clinical and morphological levels. Finally, we discuss the prospect of a therapeutic approach using immunomodulation in some patients affected by CMTs.

Alterations in cellular metabolic pathway and epithelial cell maturation induced by MYO5B defects are partially reversible by LPAR5 activation

Functional loss of the motor protein myosin Vb (MYO5B) induces various defects in intestinal epithelial function and causes a congenital diarrheal disorder, namely, microvillus inclusion disease (MVID). Utilizing the MVID model mice Vil1-CreERT2;Myo5bflox/flox (MYO5BΔIEC) and Vil1-CreERT2;Myo5bflox/G519R [MYO5B(G519R)], we previously reported that functional MYO5B loss disrupts progenitor cell differentiation and enterocyte maturation that result in villus blunting and deadly malabsorption symptoms. In this study, we determined that both absence and a point mutation of MYO5B impair lipid metabolism and alter mitochondrial structure, which may underlie the progenitor cell malfunction observed in the MVID intestine. Along with a decrease in fatty acid oxidation, the lipogenesis pathway was enhanced in the MYO5BΔIEC small intestine. Consistent with these observations in vivo, RNA sequencing of enteroids generated from the two MVID mouse strains showed similar downregulation of energy metabolic enzymes, including mitochondrial oxidative phosphorylation genes. In our previous studies, we reported that lysophosphatidic acid (LPA) signaling ameliorated epithelial cell defects in MYO5BΔIEC tissues and enteroids. The present study demonstrated that the highly soluble LPA receptor (LPAR)5-preferred agonist Compound-1 improved sodium transporter localization and absorptive function and tuft cell differentiation in patient-modeled MVID animals that carry independent mutations in MYO5B. Body weight loss in male MYO5B(G519R) mice was ameliorated by Compound-1. These observations suggest that Compound-1 treatment has a trophic effect on the intestine with MYO5B functional loss through epithelial cell-autonomous pathways that can accelerate the differentiation of progenitor cells and the maturation of enterocytes. Targeting LPAR5 may represent an effective therapeutic approach for the treatment of MVID symptoms induced by different point mutations in MYO5B.NEW & NOTEWORTHY This study demonstrates the importance of MYO5B for cellular lipid metabolism and mitochondria in intestinal epithelial cells, previously unexplored functions of MYO5B. The alterations may underlie the progenitor cell malfunction observed in microvillus inclusion disease (MVID) intestines. To examine the therapeutic potential of progenitor-targeted treatments, the effects of the LPAR5-preferred agonist Compound-1 were investigated utilizing several MVID model mice and enteroids. Our observations suggest that Compound-1 may provide a therapeutic approach for treating MVID.

Insights and implications for transcriptomic analysis of heat stress-induced intestinal inflammation in pigs

BACKGROUND

Heat stress (HS) can affect the physiology and metabolism of animals. HS-induced intestinal inflammation in pigs is a common disease, causing severe diarrhea, that can result in substantial economic losses to the pig industry, but the molecular mechanisms and pathogenicity of this disease are not fully understood. The objective of this study was to identify the differentially expressed genes (DEGs) and long noncoding RNAs (DELs) related to inflammation in the colon tissues of pigs under constant (1, 7, and 14 days) HS.

RESULTS

LncRNA and targeted gene interaction networks were constructed. GO annotation and KEGG pathway analyses were subsequently performed to determine the functions of the DEGs and DELs. The results revealed 57, 212, and 54 DEGs and 87, 79, and 55 DELs in the CON/H01, CON/H07, and CON/H14 groups, respectively. KRT85, CLDN1, S100A12, TM7SF2, CCN1, NR4A1, and several lncRNAs may be involved in regulating the development of intestinal inflammation. GO analysis indicated that the DEGs and DELs were enriched in a series of biological processes involved in the innate immune response, RAGE receptor binding, and positive regulation of the ERK1 and ERK2 cascades. KEGG pathways related to inflammation, such as the tight junction (TJ) and MAPK signaling pathways, were enriched in DEGs and DELs.

CONCLUSIONS

This study have expanded the knowledge about colon inflammation-related genes and lncRNA biology in pigs under HS; analyzed the the lncRNA‒mRNA interaction for HS-induced intestinal inflammation. These results may provide some references for our understanding of the molecular mechanism of the intestinal response to HS in pig.

Cohort Expansion and Genotype-Phenotype Analysis of RAB11A-Associated Neurodevelopmental Disorder

BACKGROUND

GTPases of the Rab family are important orchestrators of membrane trafficking, and their dysregulation has been linked to a variety of neuropathologies. In 2017, we established a causal link between RAB11A variants and developmental and epileptic encephalopathy. In this study, we expand the phenotype of RAB11A-associated neurodevelopmental disorder and explore genotype-phenotype correlations.

METHODS

We assessed 16 patients with pathogenic or likely pathogenic RAB11A variants, generally de novo, heterozygous missense variants. One individual had a homozygous nonsense variant, although concomitant with a pathogenic LAMA2 variant, which made their respective contributions to the phenotype difficult to discriminate.

RESULTS

We reinforce the finding that certain RAB11A missense variants lead to intellectual disability and developmental delays. Other clinical features might include gait disturbances, hypotonia, magnetic resonance imaging abnormalities, visual anomalies, dysmorphisms, early adrenarche, and obesity. Epilepsy seems to be less common and linked to variants outside the binding sites. Individuals with variants in the binding sites seem to have a more multisystemic, nonepileptic phenotype.

CONCLUSIONS

Similar to other Rab-related disorders, RAB11A-associated neurodevelopmental disorder can also impact gait, tonus, brain anatomy and physiology, vision, adrenarche, and body weight and structure. Epilepsy seems to affect the minority of patients with variants outside the binding sites.

Altered cellular metabolic pathway and epithelial cell maturation induced by MYO5B defects are partially reversible by LPAR5 activation

Functional loss of the motor protein, Myosin Vb (MYO5B), induces various defects in intestinal epithelial function and causes a congenital diarrheal disorder, microvillus inclusion disease (MVID). Utilizing the MVID model mice, Vil1-Cre ERT2 ;Myo5b flox/flox (MYO5BΔIEC) and Vil1-Cre ERT2 ;Myo5b flox/G519R (MYO5B(G519R)), we previously reported that functional MYO5B loss disrupts progenitor cell differentiation and enterocyte maturation that result in villus blunting and deadly malabsorption symptoms. In this study, we determined that both absence and a point mutation of MYO5B impair lipid metabolism and alter mitochondrial structure, which may underlie the progenitor cell malfunction observed in MVID intestine. Along with a decrease in fatty acid oxidation, the lipogenesis pathway was enhanced in the MYO5BΔIEC small intestine. Consistent with these observations in vivo , RNA-sequencing of enteroids generated from two MVID mouse strains showed similar downregulation of energy metabolic enzymes, including mitochondrial oxidative phosphorylation genes. In our previous studies, lysophosphatidic acid (LPA) signaling ameliorates epithelial cell defects in MYO5BΔIEC tissues and enteroids. The present study demonstrates that the highly soluble LPAR5-preferred agonist, Compound-1, improved sodium transporter localization and absorptive function, and tuft cell differentiation in patient-modeled MVID animals that carry independent mutations in MYO5B. Body weight loss in male MYO5B(G519R) mice was ameliorated by Compound-1. These observations suggest that Compound-1 treatment has a trophic effect on intestine with MYO5B functional loss through epithelial cell-autonomous pathways that may improve the differentiation of progenitor cells and the maturation of enterocytes. Targeting LPAR5 may represent an effective therapeutic approach for treatment of MVID symptoms induced by different point mutations in MYO5B.

NEW & NOTEWOTHY

This study demonstrates the importance of MYO5B for cellular lipid metabolism and mitochondria in intestinal epithelial cells, a previously unexplored function of MYO5B. Alterations in cellular metabolism may underlie the progenitor cell malfunction observed in microvillus inclusion disease (MVID). To examine the therapeutic potential of progenitor-targeted treatments, the effects of LPAR5-preferred agonist, Compound-1, was investigated utilizing several MVID model mice and enteroids. Our observations suggests that Compound-1 may provide a therapeutic approach for treating MVID.

Graphic Abstract

Rab11 and Its Role in Neurodegenerative Diseases

Vesicles mediate the trafficking of membranes/proteins in the endocytic and secretory pathways. These pathways are regulated by small GTPases of the Rab family. Rab proteins belong to the Ras superfamily of GTPases, which are significantly involved in various intracellular trafficking and signaling processes in the nervous system. Rab11 is known to play a key role especially in recycling many proteins, including receptors important for signal transduction and preservation of functional activities of nerve cells. Rab11 activity is controlled by GEFs (guanine exchange factors) and GAPs (GTPase activating proteins), which regulate its function through modulating GTP/GDP exchange and the intrinsic GTPase activity, respectively. Rab11 is involved in the transport of several growth factor molecules important for the development and repair of neurons. Overexpression of Rab11 has been shown to significantly enhance vesicle trafficking. On the other hand, a reduced expression of Rab11 was observed in several neurodegenerative diseases. Current evidence appears to support the notion that Rab11 and its cognate proteins may be potential targets for therapeutic intervention. In this review, we briefly discuss the function of Rab11 and its related interaction partners in intracellular pathways that may be involved in neurodegenerative processes.