Regulation of Myosin Light Chain Kinase during Insulin-Stimulated Glucose Uptake in 3T3-L1 Adipocytes

Myosin II (MyoII) is required for insulin-responsive glucose transporter 4 (GLUT4)-mediated glucose uptake in 3T3-L1 adipocytes. Our previous studies have shown that insulin signaling stimulates phosphorylation of the regulatory light chain (RLC) of MyoIIA via myosin light chain kinase (MLCK). The experiments described here delineate upstream regulators of MLCK during insulin-stimulated glucose uptake. Since 3T3-L1 adipocytes express two MyoII isoforms, we wanted to determine which isoform was required for insulin-stimulated glucose uptake. Using a siRNA approach, we demonstrate that a 60% decrease in MyoIIA protein expression resulted in a 40% inhibition of insulin-stimulated glucose uptake. We also show that insulin signaling stimulates the phosphorylation of MLCK. We further show that MLCK can be activated by calcium as well as signaling pathways. We demonstrate that adipocytes treated with the calcium chelating agent, 1,2-b (iso-aminophenoxy) ethane-N,N,N',N'-tetra acetic acid, (BAPTA) (in the presence of insulin) impaired the insulin-induced phosphorylation of MLCK by 52% and the RLC of MyoIIA by 45% as well as impairing the recruitment of MyoIIA to the plasma membrane when compared to cells treated with insulin alone. We further show that the calcium ionophore, A23187 alone stimulated the phosphorylation of MLCK and the RLC associated with MyoIIA to the same extent as insulin. To identify signaling pathways that might regulate MLCK, we examined ERK and CaMKII. Inhibition of ERK2 impaired phosphorylation of MLCK and insulin-stimulated glucose uptake. In contrast, while inhibition of CaMKII did inhibit phosphorylation of the RLC associated with MyoIIA, inhibition of CAMKIId did not impair MLCK phosphorylation or translocation to the plasma membrane or glucose uptake. Collectively, our results are the first to delineate a role for calcium and ERK in the activation of MLCK and thus MyoIIA during insulin-stimulated glucose uptake in 3T3-L1 adipocytes

Dual Role for Myosin II in GLUT4-Mediated Glucose Uptake in 3T3-L1 Adipocytes

Insulin-stimulated glucose uptake requires the activation of several signaling pathways to mediate the translocation and fusion of GLUT4 vesicles to the plasma membrane. Our previous studies demonstrated that GLUT4-mediated glucose uptake is a myosin II-dependent process in adipocytes. The experiments described in this report are the first to show a dual role for the myosin IIA isoform specifically in regulating insulin-stimulated glucose uptake in adipocytes. We demonstrate that inhibition of MLCK but not RhoK results in impaired insulin-stimulated glucose uptake. Furthermore, our studies show that insulin specifically stimulates the phosphorylation of the RLC associated with the myosin IIA isoform via MLCK. In time course experiments, we determined that GLUT4 translocates to the plasma membrane prior to myosin IIA recruitment. We further show that recruitment of myosin IIA to the plasma membrane requires that myosin IIA be activated via phosphorylation of the RLC by MLCK. Our findings also reveal that myosin II is required for proper GLUT-vesicle fusion at the plasma membrane. We show that once at the plasma membrane, myosin II is involved in regulating the intrinsic activity of GLUT4 after insulin stimulation. Collectively, our results are the first to reveal that myosin IIA plays a critical role in mediating insulin-stimulated glucose uptake in 3T3-LI adipocytes, via both GLUT4 vesicle fusion at the plasma membrane and GLUT4 activity

Identifying specific prefrontal neurons that contribute to autism-associated abnormalities in physiology and social behavior.

Functional imaging and gene expression studies both implicate the medial prefrontal cortex (mPFC), particularly deep-layer projection neurons, as a potential locus for autism pathology. Here, we explored how specific deep-layer prefrontal neurons contribute to abnormal physiology and behavior in mouse models of autism. First, we find that across three etiologically distinct models-in utero valproic acid (VPA) exposure, CNTNAP2 knockout and FMR1 knockout-layer 5 subcortically projecting (SC) neurons consistently exhibit reduced input resistance and action potential firing. To explore how altered SC neuron physiology might impact behavior, we took advantage of the fact that in deep layers of the mPFC, dopamine D2 receptors (D2Rs) are mainly expressed by SC neurons, and used D2-Cre mice to label D2R+ neurons for calcium imaging or optogenetics. We found that social exploration preferentially recruits mPFC D2R+ cells, but that this recruitment is attenuated in VPA-exposed mice. Stimulating mPFC D2R+ neurons disrupts normal social interaction. Conversely, inhibiting these cells enhances social behavior in VPA-exposed mice. Importantly, this effect was not reproduced by nonspecifically inhibiting mPFC neurons in VPA-exposed mice, or by inhibiting D2R+ neurons in wild-type mice. These findings suggest that multiple forms of autism may alter the physiology of specific deep-layer prefrontal neurons that project to subcortical targets. Furthermore, a highly overlapping population-prefrontal D2R+ neurons-plays an important role in both normal and abnormal social behavior, such that targeting these cells can elicit potentially therapeutic effects

More on STAT1 Gain of Function, Type 1 Diabetes, and JAK Inhibition

This is the final version. Available from the Massachusetts Medical Society via the DOI in this recor

Predictors of perceived fairness among Latinx adolescents

While most research in Latinx populations has documented that endorsing filial obligation values predicts better psychosocial outcomes, some studies have also found potential negative ramifications of the fulfillment of high levels of filial obligations, including worse academic performance and psychological maladjustment (e.g., higher depressive symptoms) (Fuligni et al., 1999). These contradictory findings may be due to the role of perceived fairness of these obligations such that filial responsibility may only lead to positive outcomes when the youth perceives the responsibility to be fair and reciprocated, but it may lead to worse outcomes when perceived to be unfair (Kuperminc et al., 2013). Despite this vital role of perceived fairness, little is known about what contributes to the perceived fairness of filial obligations. The present study examined factors nested within the acculturative process (i.e., behavioral practices, values, identity, and acculturation gap) as predictors of perceived unfairness related to familial obligations among Latinx adolescents. Results indicate that the endorsement of mainstream cultural practices and values as well as greater acculturation gap conflict are all associated with higher perceptions of unfairness. Future studies would benefit from considering the acculturative context of the sample and focusing on familial dynamics to better understand perceptions of unfairness and its impacts on psychological outcomes

Prevalence and Correlates of Common Mental Disorders among Mothers of Young Children in Kilimanjaro Region of Tanzania.

Although poor maternal mental health is a major public health problem, with detrimental effects on the individual, her children and society, information on its correlates in low-income countries is sparse. This study investigates the prevalence of common mental disorders (CMD) among at-risk mothers, and explores its associations with sociodemographic factors. This population-based survey of mothers of children aged 0-36 months used the 14-item Shona Symptom Questionnaire (SSQ). Mothers whose response was "yes" to 8 or more items on the scale were defined as "at risk of CMD." Of the 1,922 mothers (15-48 years), 28.8% were at risk of CMD. Risk of CMD was associated with verbal abuse, physical abuse, a partner who did not help with the care of the child, being in a polygamous relationship, a partner with low levels of education, and a partner who smoked cigarettes. Cohabiting appeared to be protective. Taken together, our results indicate the significance of the quality of relations with one's partner in shaping maternal mental health. The high proportion of mothers who are at risk of CMD emphasizes the importance of developing evidence-based mental health programmes as part of the care package aimed at improving maternal well-being in Tanzania and other similar settings

The role of increased reactive oxygen species on 3T3-L1 preadipocytes differentiation

Differentiation of preadipocytes plays an important role in human physiology by accommodating adipocyte expansion and maintaining energy homeostasis. Any process that interferes with preadipocytes differentiation could alter energy homeostasis. In our study, we observed the effect of increased levels of ROS, which has been shown to affect adipocyte functioning, on preadipocytes differentiation. Our study shows that increased levels of ROS can inhibit 3T3-L1 preadipocytes differentiation. While the preadipocytes eventually became resistant to the increased levels of ROS, its effect on differentiation was already fixed. The mechanism by which increased levels of ROS impaired differentiation was by decreasing and delaying Cyclin D1 expression. This would affect the phosphorylation status of retinoblastoma protein which is required for cell cycle progression into the S-phase. Since clonal expansion was halted, the activity and expression of essential transcription factors needed for differentiation C/EBPβ and PPARγ were affected, leading to impaired differentiation. Furthermore, we have shown that once the increased ROS levels are restored to lower amounts, the 3T3-L1 preadipocytes were able to differentiate into mature adipocytes when exposed to MDI. The amount of differentiation observed was diminished compared to the normally differentiating 3T3-L1 preadipocytes, but was significantly greater than cells that kept differentiating in the presence of increased ROS. Overall, we have outlined the timeframe during which oxidative stress impairs 3T3-L1 preadipocyte differentiation. We have shown that, once that increased ROS levels are lowered, differentiation can be restored, but not to the same degree as unstressed differentiating 3T3-L1 preadipocytes

The methods and outcomes of cultural adaptations of psychological treatments for depressive disorders: a systematic review.

BACKGROUND: Cultural adaptations of evidence-based psychological treatments (PTs) are important to enhance their universal applicability. The aim of this study was to review systematically the literature on adaptations of PTs for depressive disorders for ethnic minorities in Western countries and for any population in non-Western countries to describe the process, extent and nature of the adaptations and the effectiveness of the adapted treatments. METHOD: Controlled trials were identified using database searches, key informants, previous reviews and reference lists. Data on the process and details of the adaptations were analyzed using qualitative methods and meta-analysis was used to assess treatment effectiveness. RESULTS: Twenty studies were included in this review, of which 16 were included in the meta-analysis. The process of adaptation was reported in two-thirds of the studies. Most adaptations were found in the dimensions of language, context and therapist delivering the treatment. The meta-analysis revealed a statistically significant benefit in favor of the adapted treatment [standardized mean difference (SMD) -0.72, 95% confidence interval (CI) -0.94 to -0.49]. CONCLUSIONS: Cultural adaptations of PTs follow a systematic procedure and lead primarily to adaptations in the implementation of the treatments rather than their content. Such PTs are effective in the treatment of depressive disorders in populations other than those for whom they were originally developed

Should providers encourage realistic weight expectations and satisfaction with lost weight in commercial weight loss programs? a preliminary study

Background Attrition is a problem among patients who participate in commercial weight loss programs. One possible explanation is that if patients are unable to reach a weight that they expect to achieve, they may be more likely to drop out of treatment. This study investigated variables associated with attrition among 30 obese patients who completed a liquid meal replacement program (LMR) and enrolled in a 52-week Small Changes Maintenance intervention (SCM). Patients lost a median 18% of body weight during LMR and completed assessments about weight expectations and weight satisfaction pre- and post-SCM. Findings Of the 30 patients who started SCM, 8 (27%) were lost to attrition. Odds of SCM attrition were higher in patients who lost ≤ 18.2% of pre-LMR weight (OR: 12.25, P = 0.035), had lower satisfaction (≤7) pre-SCM (OR: 10.11, P = 0.040), and who expected further weight loss of 9.1 kg or more pre-SCM (OR: 10.11, P = 0.040). SCM completers significantly increased weight loss expectations by a median of 2.3 kg from pre-SCM to post-SCM (WSR P = 0.049) that paralleled weight regained post-SCM (2.7 kg). Conclusions After completion of a medically-supervised commercial weight loss program, patients with the greatest expectations for further weight loss and the lowest weight satisfaction were more likely to drop out of SCM. Failure to participate in maintenance treatment may lead to regain of greater than half of lost weight over the next year. Among SCM completers, lower expectations for further weight loss and greater weight satisfaction appeared to be associated with continued engagement in maintenance treatment

Penetrance and expressivity of mitochondrial variants in a large clinically unselected population

\ua9 The Author(s) 2023. Published by Oxford University Press. Whole genome sequencing (WGS) from large clinically unselected cohorts provides a unique opportunity to assess the penetrance and expressivity of rare and/or known pathogenic mitochondrial variants in population. Using WGS from 179 862 clinically unselected individuals from the UK Biobank, we performed extensive single and rare variant aggregation association analyses of 15 881 mtDNA variants and 73 known pathogenic variants with 15 mitochondrial disease-relevant phenotypes. We identified 12 homoplasmic and one heteroplasmic variant (m.3243A>G) with genome-wide significant associations in our clinically unselected cohort. Heteroplasmic m.3243A>G (MAF = 0.0002, a known pathogenic variant) was associated with diabetes, deafness and heart failure and 12 homoplasmic variants increased aspartate aminotransferase levels including three low-frequency variants (MAF ~0.002 and beta~0.3 SD). Most pathogenic mitochondrial disease variants (n = 66/74) were rare in the population (<1:9000). Aggregated or single variant analysis of pathogenic variants showed low penetrance in unselected settings for the relevant phenotypes, except m.3243A>G. Multi-system disease risk and penetrance of diabetes, deafness and heart failure greatly increased with m.3243A>G level ≥ 10%. The odds ratio of these traits increased from 5.61, 12.3 and 10.1 to 25.1, 55.0 and 39.5, respectively. Diabetes risk with m.3243A>G was further influenced by type 2 diabetes genetic risk. Our study of mitochondrial variation in a large-unselected population identified novel associations and demonstrated that pathogenic mitochondrial variants have lower penetrance in clinically unselected settings. m.3243A>G was an exception at higher heteroplasmy showing a significant impact on health making it a good candidate for incidental reporting