Yes-associated protein reduces neuroinflammation through upregulation of Sirt3 and inhibition of JNK signaling pathway

Intermittent fasting promotes adipocyte mitochondrial fusion through Sirt3-mediated deacetylation of Mdh2

Fat deposition and lipid metabolism are closely related to the morphology, structure and function of mitochondria. The morphology of mitochondria between fusion and fission processes is mainly regulated by protein posttranslational modification. Intermittent fasting (IF) promotes high expression of Sirtuin 3 (Sirt3) and induces mitochondrial fusion in high-fat diet (HFD)-fed mice. However, the mechanism by which Sirt3 participates in mitochondrial protein acetylation during IF to regulate mitochondrial fusion and fission dynamics remains unclear. This article demonstrates that IF promotes mitochondrial fusion and improves mitochondrial function in HFD mouse inguinal white adipose tissue. Proteomic sequencing revealed that IF increased protein deacetylation levels in HFD mice and significantly increased Sirt3 mRNA and protein expression. After transfecting with Sirt3 overexpression or interference vectors into adipocytes, we found that Sirt3 promoted adipocyte mitochondrial fusion and improved mitochondrial function. Furthermore, Sirt3 regulates the JNK-FIS1 pathway by deacetylating malate dehydrogenase 2 (MDH2) to promote mitochondrial fusion. In summary, our study indicates that IF promotes mitochondrial fusion and improves mitochondrial function by upregulating the high expression of Sirt3 in HFD mice, promoting deacetylation of MDH2 and inhibiting the JNK-FIS1 pathway. This research provides theoretical support for studies related to energy limitation and animal lipid metabolism.

YAP at the progression of inflammation

Yes-associated protein (YAP) is a transcriptional regulator that affects cell proliferation, organ size and tissue development and regeneration, and has therefore, been an important object of study. In recent years, there has been an increasing research focus on YAP in inflammation and immunology, and the role of YAP in the development of inflammation and in immune escape by tumors has been progressively elucidated. Because YAP signaling involves a variety of different signal transduction cascades, the full range of functions in diverse cells and microenvironments remains incompletely understood. In this article, we discuss the complex involvement of YAP in inflammation, the molecular mechanisms through which it exercises pro- and anti-inflammatory effects under different conditions, and the progress achieved in elucidating the functions of YAP in inflammatory diseases. A thorough understanding of YAP signaling in inflammation will provide a foundation for its use as a therapeutic target in inflammatory diseases.

Genome-wide DNA methylation study identifies significant epigenomic changes associated with internalized stigma in adults with non-specific chronic low back pain

Non-specific chronic low back pain (cLBP) represents a common musculoskeletal condition with no identifiable cause. It cannot be diagnosed with conventional neuroimaging techniques such as computerized tomography (CT). The diagnostic uncertainty that characterizes non-specific cLBP can lead to stigmatizing responses from others that can become internalized Among individuals with non-specific cLBP, internalized stigma is associated with greater pain intensity and disability. Yet, no study has examined the biological mechanism linking high internalized stigma to worse outcomes in individuals with non-specific cLBP. We aimed to identify differentially methylated loci (DML), enrichment pathways, and associated network interactions among individuals with non-specific cLBP experiencing low vs. high internalized stigma. We examined DNA methylation in whole blood samples from 48 adults, ages 19-85, using reduced representation bisulfite sequencing (RRBS). After controlling for age, sex, race, and multiple testing, differentially methylated loci (DML) differed in adults with low vs. high internalized stigma by at least 10% and q < 0.01 in 3,665 CpG sites: 2,280 hypomethylated and 1,385 hypermethylated. Gene ontology (GO) analyses of the annotated genes from these sites revealed significant enrichment of 274 biological processes, 29 cellular components, and 24 molecular functions (adjusted p < 0.05). The top enriched molecular functions regulate protein binding and DNA binding of transcription factor activity. Pathway analyses indicated that many functional genomic pathways, including Hippo Signaling, Melanogenesis, and Pathways in Cancer, were enriched with differentially methylated genes. Also, there was a significant interaction between relevance pathways such as P53, mTOR, PI3K-Akt, and Wnt signaling pathways. These pathways have previously been associated with neuroinflammation, neurodegeneration, and stress-related conditions. Thus, findings point to possible stress-induced DNAm changes as the link between high levels of internalized stigma and worse outcomes in adults with non-specific cLBP.

Spinal Sirtuin 3 Contributes to Electroacupuncture Analgesia in Mice with Chronic Constriction Injury–Induced Neuropathic Pain

BACKGROUND

Electroacupuncture (EA) is a traditional Chinese therapeutic technique that has a beneficial effect on neuropathic pain; however, the specific mechanism remains unclear. In this study, we investigated whether EA inhibits spinal Ca/calmodulin-dependent protein kinase II (CaMKIIα) phosphorylation through Sirtuin 3 (SIRT3) protein, thus relieving neuropathic pain.

MATERIALS AND METHODS

We used wild-type and SIRT3 knockout (SIRT3^-/-) mice and used chronic constriction injury (CCI) as a pain model. We performed Western blotting, immunostaining, von Frey, and Hargreaves tests to gather biochemical and behavioral data. Downregulation and overexpression and spinal SIRT3 protein were achieved by intraspinal injection of SIRT3 small interfering RNA and intraspinal injection of lentivirus-SIRT3. To test the hypothesis that CaMKIIα signaling was involved in the analgesic effects of EA, we expressed CaMKIIα-specific designer receptors exclusively activated by designer drugs (DREADDs) in the spinal dorsal horn (SDH) of mice.

RESULTS

These results showed that the mechanical and thermal hyperalgesia induced by CCI was related to the decreased spinal SIRT3 expression in the SDH of mice. A significant reduction of mechanical and thermal thresholds was found in the SIRT3^-/- mice. SIRT3 overexpression or EA treatment alleviated CCI-induced neuropathic pain and prevented the spinal CaMKIIα phosphorylation. Most importantly, EA increased the expression of spinal SIRT3 protein in the SDH. Downregulation of spinal SIRT3 or CaMKIIα Gq-DREADD activation inhibited the regulatory effect of EA on neuropathic pain.

CONCLUSION

Our results showed that CaMKIIα phosphorylation was inhibited by spinal SIRT3 in neuropathic pain and that EA attenuated CCI-induced neuropathic pain mainly by upregulating spinal SIRT3 expression in the SDH of mice.

Transcriptional Modulation of the Hippo Signaling Pathway by Drugs Used to Treat Bipolar Disorder and Schizophrenia

Recent reports suggest a link between positive regulation of the Hippo pathway with bipolar disorder (BD), and the Hippo pathway is known to interact with multiple other signaling pathways previously associated with BD and other psychiatric disorders. In this study, neuronal-like NT2 cells were treated with amisulpride (10 µM), aripiprazole (0.1 µM), clozapine (10 µM), lamotrigine (50 µM), lithium (2.5 mM), quetiapine (50 µM), risperidone (0.1 µM), valproate (0.5 mM), or vehicle control for 24 h. Genome-wide mRNA expression was quantified and analyzed using gene set enrichment analysis (GSEA), with genes belonging to Hippo, Wnt, Notch, TGF- β, and Hedgehog retrieved from the KEGG database. Five of the eight drugs downregulated the genes of the Hippo pathway and modulated several genes involved in the interacting pathways. We speculate that the regulation of these genes, especially by aripiprazole, clozapine, and quetiapine, results in a reduction of MAPK and NFκB pro-inflammatory signaling through modulation of Hippo, Wnt, and TGF-β pathways. We also employed connectivity map analysis to identify compounds that act on these pathways in a similar manner to the known psychiatric drugs. Thirty-six compounds were identified. The presence of antidepressants and antipsychotics validates our approach and reveals possible new targets for drug repurposing.

The Effects of YAP and Its Related Mechanisms in Central Nervous System Diseases

Yes-associated protein (YAP) is a key effector downstream of the Hippo signaling pathway and plays an important role in the development of the physiology and pathology of the central nervous system (CNS), especially regulating cell proliferation, differentiation, migration, and apoptosis. However, the roles and underlying mechanisms of YAP in CNS diseases are still puzzling. Here, this review will systematically and comprehensively summarize the biological feature, pathological role, and underlying mechanisms of YAP in normal and pathologic CNS, which aims to provide insights into the potential molecular targets and new therapeutic strategies for CNS diseases.