CAPA periviscerokinin-mediated activation of MAPK/ERK signaling through Gq-PLC-PKC-dependent cascade and reciprocal ERK activation-dependent internalized kinetics of Bom-CAPA-PVK receptor 2

Advances in the extracellular signal-regulated kinase signaling pathway in silkworms, Bombyx mori (Lepidoptera)

Signaling pathways regulate the transmission of signals during organism growth and development, promoting the smooth and accurate completion of numerous physiological and biochemical reactions. The extracellular signal-regulated kinase (ERK) signaling pathway is an essential pathway involved in regulating various physiological processes, such as cell proliferation, differentiation, adhesion, migration, and more. This pathway also contributes to several important physiological processes in silkworms, including protein synthesis, reproduction, and immune defense against pathogens. Organizing related studies on the ERK signaling pathway in silkworms can provide a better understanding of its mechanism in Lepidopterans and develop a theoretical foundation for improving cocoon production and new strategies for pest biological control.

Lymphocytic Extracellular Signal-Regulated Kinase Dysregulation in Autism Spectrum Disorder

OBJECTIVE

Extracellular signal-regulated kinase (ERK1/2) is a conserved central intracellular signaling cascade involved in many aspects of neuronal development and plasticity. Converging evidence support investigation of ERK1/2 activity in autism spectrum disorder (ASD). We previously reported enhanced baseline lymphocytic ERK1/2 activation in autism, and now we extend our work to investigate the early phase kinetics of lymphocytic ERK1/2 activation in idiopathic ASD.

METHOD

Study participants included 67 individuals with ASD (3-25 years of age), 65 age- and sex-matched typical developing control (TDC) subjects, and 36 age-, sex-, and IQ-matched developmental disability control (DDC) subjects matched to those with ASD and IQ <90. We completed an additional analysis comparing results from ASD, TDC, and DDC groups with data from 37 individuals with Fragile X syndrome (FXS). All subjects had blood lymphocyte samples analyzed by flow cytometry following stimulation with phorbol ester and sequentially analyzed for ERK1/2 activation (phosphorylation) at several time points.

RESULTS

The ASD group (mean = 5.81 minutes; SD = 1.5) had a significantly lower (more rapid) mean ERK1/2 T_1/2 activation value than both the DDC group (mean = 6.78 minutes; SD = 1.6; p = .00078) and the TDC group (mean = 6.4 minutes; SD = 1.5; p = .025). More rapid ERK1/2 T_1/2 activation times did correlate with increased social impairment across all study groups including the ASD cohort. Differences in ERK1/2 T_1/2 activation were more pronounced in younger than in older individuals in the primary analysis. The ASD group additionally had more rapid activation times than the FXS group, and the FXS group activation kinetics did not differ from those of the TDC and DDC groups.

CONCLUSION

Our findings indicate that lymphocytic ERK1/2 activation kinetics are dysregulated in persons with ASD, marked by more rapid early phase activation. Group differences in ERK1/2 activation kinetics appear to be driven by findings from the youngest children analyzed.

DIVERSITY & INCLUSION STATEMENT

We worked to ensure sex and gender balance in the recruitment of human participants. We actively worked to promote sex and gender balance in our author group. The author list of this paper includes contributors from the location and/or community where the research was conducted who participated in the data collection, design, analysis, and/or interpretation of the work.

Acetic acid stimulates G-protein-coupled receptor GPR43 and induces intracellular calcium influx in L6 myotube cells

Short chain fatty acids (SCFAs) produced endogenously in the gut by bacterial fermentation of dietary fiber have been studied as nutrients that act as signaling molecules to activate G-protein coupled receptors (GPCRs) such as GPR41 and GPR43. GPR43 functioning involves the suppression of lipid accumulation and maintaining body energy homeostasis, and is activated by acetic acid or propionic acid. Previously, we reported that the orally administered acetic acid improves lipid metabolism in liver and skeletal muscles and suppresses obesity, thus improving glucose tolerance. Acetic acid stimulates AMP-activated protein kinase (AMPK) through its metabolic pathway in skeletal muscle cells. We hypothesized that acetic acid would stimulate GPR43 in skeletal muscle cells and has function in modulating gene expression related to muscle characteristics through its signal pathway. The objective of the current study was to clarify this effect of acetic acid. The GPR43 expression, observed in the differentiated myotube cells, was increased upon acetic acid treatment. Acetic acid induced the intracellular calcium influx in the cells and this induction was significantly inhibited by the GPR43-specific siRNA treatment. The calcineurin molecule is activated by calcium/calmodulin and is associated with proliferation of slow-twitch fibers. Calcineurin was activated by acetic acid treatment and inhibited by the concomitant treatment with GPR43-siRNA. Acetic acid induced nuclear localization of myocyte enhancer factor 2A (MEF2A), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), and nuclear factor of activated t cells c1 (NFATc1). However, these localizations were abolished by the treatment with GPR43-siRNA. It was concluded that acetic acid plays a role in the activation of GPR43 and involves the proliferation of slow-twitch fibers in L6 skeletal muscles through the calcium-signaling pathway caused by induction of intracellular calcium influx.