β-Catenin Controls the Electrophysiologic Properties of Skeletal Muscle Cells by Regulating the α2 Isoform of Na+/K+-ATPase

Impact of Prematurity on the Buccal Epithelial Cells of the Neonates via Wnt/Beta-Catenin Signaling Pathway and Apoptosis

OBJECTIVE

 Understanding the reflections of prematurity is necessary for the management of neonatal complications. We focused on the impact of prematurity and related "maternal risk factors/obstetric complications" on buccal cells of the neonates via evaluation of the Wnt/β-catenin signaling pathway and apoptosis.

STUDY DESIGN

 This study consisted of "early preterm neonates (EPN) (≤34th gestational week [gw]) (n = 36)," "late preterm neonates (LPN) (34th- < 37th gw) (n = 46)," and "term neonates (control) (≥37th gw) (n = 56)." Cohort was also subclassified according to the presence of maternal risk factors, obstetric complications, and neonatal complications. Wnt/β-catenin signaling and caspase-3 activation pathways were studied immunocytochemically.

RESULTS

 Wnt/β-catenin signaling positivity was statistically more frequent at buccal smears of the EPN and LPN groups compared with controls (p < 0.001). The cutoff for gestational age at delivery in receiver operating characteristic curve with the best balance of sensitivity (67.4%) and specificity (67.3%) was 35.8th gw for determining the reduction of Wnt/β-catenin signaling positivity (p < 0.001). The study demonstrated that obstetric complications significantly affected the activity of signaling, while maternal risk factors do not have any effect on Wnt/β-catenin signaling pathway (p = 0.003 and p = 0.828, respectively). This study also demonstrated a significant relationship between Wnt/β-catenin signaling pathway and the presence of neonatal complications (p = 0.015).

CONCLUSION

 Dynamic characteristics of buccal cells are influenced by prematurity and related obstetric and neonatal problems. Buccal smear is a good tool to investigate the impact of prematurity and obstetric problems on perinatal outcome.

KEY POINTS

· Neonatal buccal cells are affected by prematurity and related obstetric/neonatal problems.. · 35.8th gw is critical for determining the reduction of Wnt/β-catenin signaling positivity.. · Obstetric and neonatal complications significantly related to Wnt/β-catenin signaling activity..

Regulation of Myogenesis by a Na/K-ATPase α1 Caveolin-Binding Motif

The N-terminal caveolin-binding motif (CBM) in Na/K-ATPase (NKA) α1 subunit is essential for cell signaling and somitogenesis in animals. To further investigate the molecular mechanism, we have generated CBM mutant human-induced pluripotent stem cells (iPSCs) through CRISPR/Cas9 genome editing and examined their ability to differentiate into skeletal muscle (Skm) cells. Compared with the parental wild-type human iPSCs, the CBM mutant cells lost their ability of Skm differentiation, which was evidenced by the absence of spontaneous cell contraction, marker gene expression, and subcellular myofiber banding structures in the final differentiated induced Skm cells. Another NKA functional mutant, A420P, which lacks NKA/Src signaling function, did not produce a similar defect. Indeed, A420P mutant iPSCs retained intact pluripotency and ability of Skm differentiation. Mechanistically, the myogenic transcription factor MYOD was greatly suppressed by the CBM mutation. Overexpression of a mouse Myod cDNA through lentiviral delivery restored the CBM mutant cells' ability to differentiate into Skm. Upstream of MYOD, Wnt signaling was demonstrated from the TOPFlash assay to have a similar inhibition. This effect on Wnt activity was further confirmed functionally by defective induction of the presomitic mesoderm marker genes BRACHYURY (T) and MESOGENIN1 (MSGN1) by Wnt3a ligand or the GSK3 inhibitor/Wnt pathway activator CHIR. Further investigation through immunofluorescence imaging and cell fractionation revealed a shifted membrane localization of β-catenin in CBM mutant iPSCs, revealing a novel molecular component of NKA-Wnt regulation. This study sheds light on a genetic regulation of myogenesis through the CBM of NKA and control of Wnt/β-catenin signaling.

Aberrations in the Cross-Talks Among Redox, Nuclear Factor-κB, and Wnt/β-Catenin Pathway Signaling Underpin Myalgic Encephalomyelitis and Chronic Fatigue Syndrome

There is evidence that chronic fatigue spectrum disorders (CFAS-Ds), including myalgic encephalomyelitis (ME), chronic fatigue syndrome (CFS), and chronic fatigue with physiosomatic symptoms including when due to comorbid medical disease, are characterized by neuroimmune and neuro-oxidative biomarkers. This study was performed to delineate the protein-protein interaction (PPI) network of CFAS-D and to discover the pathways, molecular patterns, and domains enriched in their PPI network. We performed network, enrichment, and annotation analyses using differentially expressed proteins and metabolics, which were established in patients with CFAS-D. The PPI network analysis revealed that the backbone of the highly connective CFAS-D network comprises NFKB1, CTNNB1, ALB, peroxides, NOS2, tumor necrosis factor (TNF), and interleukin-6 (IL-6) and that the network comprises interconnected immune-oxidative-nitrosative and Wnt/β-catenin subnetworks. Multiomics enrichment analysis shows that the CFAS-D network is highly significantly associated with cellular (antioxidant) detoxification, hydrogen peroxide metabolic process, peroxidase and oxidoreductase activity, interleukin-10 (IL-10) anti-inflammatory signaling and neurodegenerative canonical Wnt, the β-catenin complex, cadherin domains, cell-cell junctions and TLR2/4 pathways, and the transcription factors nuclear factor kappa B (NF-κB) and RELA. The top 10 DOID annotations of the CFAS-D network include four intestinal, three immune system disorders, cancer, and infectious disease. The custom Gene Ontology (GO) term annotation analysis revealed that the CFAS-D network is associated with a response to a toxic substance, lipopolysaccharides, bacterium, or virus. In conclusion, CFAS-D may be triggered by a variety of stimuli and their effects are mediated by aberrations in the cross-talks between redox, NF-κB, and Wnt/β-catenin signaling pathways leading to dysfunctions in multicellular organismal homeostatic processes.