Regulation Of Homeostasis Research Articles

Shear stress-stimulated AMPK couples endothelial cell mechanics, metabolism and vasodilation.

Endothelial cells respond to mechanical force by stimulating cellular signaling, but how these pathways are linked to elevations in cell metabolism and whether metabolism supports the mechanical response remains poorly understood. Here, we show that the application of force to endothelial cells stimulates VE-cadherin to activate liver kinase B1 (LKB1; also known as STK11) and AMP-activated protein kinase (AMPK), a master regulator of energy homeostasis. VE-cadherin-stimulated AMPK increases eNOS (also known as NOS3) activity and localization to the plasma membrane, reinforcement of the actin cytoskeleton and cadherin adhesion complex, and glucose uptake. We present evidence for the increase in metabolism being necessary to fortify the adhesion complex, actin cytoskeleton and cellular alignment. Together, these data extend the paradigm for how mechanotransduction and metabolism are linked to include a connection to vasodilation, thereby providing new insight into how diseases involving contractile, metabolic and vasodilatory disturbances arise.

Nuclear lipid droplets: a novel regulator of nuclear homeostasis and ageing.

Aging is a fundamental driver of numerous life-threatening diseases, significantly compromising cellular structures and functions, including the integrity of the nucleus. A consistent feature of aging across diverse species is the progressive accumulation of lipid droplets (nLDs) within the nuclear compartment, which disrupts nuclear architecture and functionality. Notably, aging is accompanied by a marked increase in nLD accumulation at the nuclear envelope. Interventions known to extend lifespan, such as caloric restriction and reduced insulin signaling, significantly reduce both the rate of accumulation and the size of nLDs. The triglyceride lipase ATGL-1, which localizes to the nuclear envelope, plays a critical role in limiting nLD buildup and maintaining nuclear lipid balance, especially in long-lived mutant worms. These findings establish excessive nuclear lipid deposition as a key hallmark of aging, with profound implications for nuclear processes such as chromatin organization, DNA repair, and gene regulation. In addition, ATGL-1 emerges as a promising therapeutic target for preserving nuclear health, extending organismal healthspan, and combating age-related disorders driven by lipid dysregulation.

Characteristic Muscle Quality Parameters of Male Largemouth Bass (Micropterus salmoides) Distinguished from Female and Physiological Variations Revealed by Transcriptome Profiling

Male largemouth bass (Micropterus salmoides) are often overlooked because females grow faster. We explored the value of male largemouth bass by comparing muscle nutrition, texture, and transcriptomes between males and females. Females grew faster than males (p < 0.05) because of lipid accumulation. Male fish muscles had higher contents of serine, valine, methionine, arginine, nervonic acid, and α-linolenic acid (p < 0.05), and female fish muscles had higher contents of aspartic acid, glycine, cysteine, leucine, palmitic acid, docosahexaenoic acid, and 11,14,17-eicosatrienoic acid (p < 0.05). Male muscles had a higher concentration of collagen fibers and greater shear force, indicative of a chewier texture. Male muscles had a lighter color, suggesting that they were less susceptible to oxidation and deterioration. Transcriptomic analyses revealed upregulation of lpl, sadb, dgat2, bhmt, tecrb, and hsd3b7, encoding components of amino acid and fatty acid metabolism; and upregulation of akt2, src, and kras, encoding crucial regulators of cellular immunity and homeostasis, in male muscles. Immunity-related pathways, including apoptosis, ErbB signaling, and cellular senescence, were enriched in male fish muscles, indicating heightened immune function. The muscles of male fish have a unique profile and distinctive advantages in terms of nutrition, flavor, texture, and transcriptional regulation.

Cysteine Rich Intestinal Protein 2 is a copper-responsive regulator of skeletal muscle differentiation and metal homeostasis.

Copper (Cu) is essential for respiration, neurotransmitter synthesis, oxidative stress response, and transcription regulation, with imbalances leading to neurological, cognitive, and muscular disorders. Here we show the role of a novel Cu-binding protein (Cu-BP) in mammalian transcriptional regulation, specifically on skeletal muscle differentiation using murine primary myoblasts. Utilizing synchrotron X-ray fluorescence-mass spectrometry, we identified murine cysteine-rich intestinal protein 2 (mCrip2) as a key Cu-BP abundant in both nuclear and cytosolic fractions. mCrip2 binds two to four Cu+ ions with high affinity and presents limited redox potential. CRISPR/Cas9-mediated deletion of mCrip2 impaired myogenesis, likely due to Cu accumulation in cells. CUT&RUN and transcriptome analyses revealed its association with gene promoters, including MyoD1 and metallothioneins, suggesting a novel Cu-responsive regulatory role for mCrip2. Our work describes the significance of mCrip2 in skeletal muscle differentiation and metal homeostasis, expanding understanding of the Cu-network in myoblasts. Copper (Cu) is essential for various cellular processes, including respiration and stress response, but imbalances can cause serious health issues. This study reveals a new Cu-binding protein (Cu-BP) involved in muscle development in primary myoblasts. Using unbiased metalloproteomic techniques and high throughput sequencing, we identified mCrip2 as a key Cu-BP found in cell nuclei and cytoplasm. mCrip2 binds up to four Cu+ ions and has a limited redox potential. Deleting mCrip2 using CRISPR/Cas9 disrupted muscle formation due to Cu accumulation. Further analyses showed that mCrip2 regulates the expression of genes like MyoD1, essential for muscle differentiation, and metallothioneins in response to copper supplementation. This research highlights the importance of mCrip2 in muscle development and metal homeostasis, providing new insights into the Cu-network in cells.

Lack of correlation between asprosin serum levels and hyperphagic behavior in subjects with prader-Willi Syndrome.

Individuals with Prader-Willi syndrome (PWS) exhibit hyperphagic behavior, the severity of which varies throughout life. The mechanisms underlying this behavior are still unknown. Asprosin is a new discovered adipokine involved in the regulation of food intake, glucose homeostasis and energy balance. In this study we assessed asprosin serum levels in a cohort of children, adolescents and adults with PWS with the aim to correlate them with hyperphagic behavior, body mass index (BMI) and metabolic parameters, and to evaluate age-related changes. This cross-sectional study included 87 children and adolescents and 31 adults with PWS. Auxological data, fasting levels of glucose, insulin, total cholesterol, high-density lipoprotein-cholesterol (HDL-C), triglycerides (TG) and asprosin were collected, and the homeostasis model assessment for insulin resistance (HOMA-IR) was determined. The 11-item Italian version of the Hyperphagia Questionnaire (HQ) was administered to the parents/caregivers of the patients to assess hyperphagia. Patients were analysed according to age (children < 10 years, adolescents between 10 and 17.9 years, adults ≥ 18 years) or BMI categories [normal weight (NW), overweight (OW), and obesity (OB)]. No significant correlations were found between asprosin levels and cardiometabolic risk factors in the whole cohort. Higher values of asprosin were found in adults compared with adolescents, as well as in the OB group compared to the NW group (p = 0.014). Hyperphagia total score and hyperphagic subdimensions were significantly lower in children compared to adults (p < 0.05). Similarly, hyperphagia total score and hyperphagic subdimensions were significantly lower in the NW group compared to the OB group. Asprosin levels were significantly higher in patients with deletion versus patients with uniparental disomy (p = 0.037). By logistic regression analysis, HQ total score and hyperphagic subdimensions were significantly associated with BMI-SDS independently of age, sex, and asprosin levels. In conclusion, our data demonstrated higher asprosin levels in PWS individuals with OB compared to NW, while differences by age and sex were inconsistent. The lower levels of hyperphagia, BMI-SDS, and metabolic variables in children with PWS compared to adults underline that prevention of obesity should start very early in life and should be maintained over time.

Silicon regulation of manganese homeostasis in plants: mechanisms and future prospective

Silicon regulation of manganese homeostasis in plants: mechanisms and future prospective

Calcium sensing receptor regulate claudin-14 via PKA-STAT3 pathway in rat model of nephrolithiasis.

The calcium-sensitive receptor (CaSR) has been identified as a key factor in the formation of kidney stones. A substantial body of research has illuminated the function of CaSR in stone formation with respect to oxidative stress, epithelial injury, crystal adhesion, and stone-associated proteins. Nevertheless, as a pivotal molecule in renal calcium excretion, its pathway that contributes to stone formation by regulating calcium supersaturation remains underexplored. An in vitro rat calcium oxalate kidney stone model was established through the co-cultivation of calcium oxalate monohydrate (COM) with NRK-52E cells, while an in vivo model was constructed using the ethylene glycol method. Subsequently, the level of the CaSR-claudin-14 pathway was determined. To further elucidate the molecular pathway of CaSR-mediated regulation of claudin-14, drugs were selectively added to the in vitro and ex vivo kidney stone models, and the expression of claudin-14 and the levels of stone formation were detected. Moreover, the direct regulation of claudin-14 by CaSR with STAT3 serving as a transcription factor was examined via the dual luciferase assay. Eventually, a Cldn-14 knockout rat model and a model of kidney stone induction by ethylene glycol were generated using CRISPR-Cas9 technology to further clarify the role of claudin-14 in the CaSR-regulated formation of kidney stones. In vitro and in vivo observations revealed that calcium oxalate induces high expression of CaSR-claudin-14. Specifically, CaSR regulates claudin-14 expression through phosphorylation modification of STAT3 via protein kinase A (PKA). In vitro, the intervention of PKA and STAT3 reversed the elevated claudin-14 levels and stone formation induced by CaSR. Finally, we generated cldn-14 knockout rats using CRISPR-Cas9 technology and observed that ethylene glycol still induced stone formation in these animals. Nevertheless, the specific activation or inhibition of CaSR demonstrated no notable impact on stone formation. The results of our study indicate that calcium oxalate crystals induce the activation of the pro-stone pathway of CaSR. That is, activated CaSR regulates claudin-14 levels via the PKA-STAT3 pathway, which further promotes calcium salt stone formation. The role of CaSR in the regulation of stone homeostasis is further enriched.

GLP-1 receptor agonists and delayed gastric emptying: implications for invasive cardiac interventions and surgery.

Glucagon-like peptide-1 (GLP-1) is a hormone involved in glucose homeostasis and satiety regulation. The review highlights the importance of understanding the interplay between GLP-1 and gastric motility. This paper explores the intricate connection between GLP-1 and delayed gastric emptying, specifically gastroparesis, and its implications in the context of pulmonary aspiration during anesthesia along with the potential effects of GLP-1 medications on absorption of other medications. The findings noted in this paper serve as a catalyst for continued exploration into the intricate dynamics of GLP-1 and its implications in the context of perioperative care, aiming to enhance patient safety and optimize anesthesia practices. The inquiry suggests that an in-depth examination of this relationship is crucial for refining perioperative management strategies. It underscores the need for further research to elucidate the mechanisms involved and to establish guidelines that address the potential risks associated with GLP-1 modulation, particularly in patients undergoing anesthesia for various cardiac surgeries and procedures. Specifically in the context of cardiac interventions understanding the potential for delayed absorption of critical cardiac medications due to the influence of GLP-1 on gastric emptying is particularly important as drug absorption can play a crucial role for ensuring successful outcomes.

SIX transcription factors are necessary for the activation of DUX4 expression in facioscapulohumeral muscular dystrophy

BackgroundFacioscapulohumeral muscular dystrophy (FSHD) is a common and progressive muscle wasting disease that is characterized by muscle weakness often first noticed in the face, the shoulder girdle and upper arms before progressing to the lower limb muscles. FSHD is caused by the misexpression of the Double Homeobox 4 (DUX4) transcription factor in skeletal muscle. While epigenetic derepression of D4Z4 macrosatellite repeats underlies DUX4 misexpression, our understanding of the complex transcriptional activation of DUX4 is incomplete.MethodsTo identify potential DUX4-regulatory factors, we used small interfering RNAs (siRNAs) to knockdown SIX family transcription factors (SIX1, 2, 4, 5) in patient-derived FSHD1 and FSHD2 myoblasts that were differentiated to form multinucleated myotubes. Quantitative real-time polymerase chain reaction was used to measure changes in DUX4 mRNA, DUX4 target gene expression and myogenic markers. Staining for SIX1 and SIX2 with specific antibodies was performed in FSHD myoblasts and myotubes. To assess reciprocal effects of DUX4 on SIX1, 2, and 4 expression, we utilized a doxycycline-inducible DUX4 myoblast cell line.ResultWe show that SIX1, 2 and 4 transcription factors, regulators of embryonic development, muscle differentiation, regeneration and homeostasis, are necessary for myogenic differentiation-dependent DUX4 expression in FSHD muscle cells. Using siRNA, we demonstrate SIX1, SIX2, and SIX4 to be critical factors involved in the induction of DUX4 transcription in differentiating FSHD myotubes in vitro. siRNA dual knockdown of SIX1 and SIX2 resulted in a ~ 98% decrease of DUX4 and DUX4 target genes, suggesting that SIX1 and SIX2 are the most critical in promoting DUX4 expression. Importantly, we show that DUX4 downregulates SIX RNA levels, suggesting negative feedback regulation.ConclusionsIn this study, we identified a family of developmental regulators that promote aberrant DUX4 expression in FSHD1 and FSHD2 differentiating muscle cells. Our findings highlight the critical involvement of SIX transcription factors (SIX1, 2, 4) in the pathogenesis of FSHD by serving as necessary factors that function in the promotion of DUX4 expression following epigenetic derepression of the D4Z4 repeats.

Seipin governs phosphatidic acid homeostasis at the inner nuclear membrane

The nuclear envelope is a specialized subdomain of the endoplasmic reticulum and comprises the inner and outer nuclear membranes. Despite the crucial role of the inner nuclear membrane in genome regulation, its lipid metabolism remains poorly understood. Phosphatidic acid (PA) is essential for membrane growth as well as lipid storage. Using a genome-wide lipid biosensor screen in S. cerevisiae, we identify regulators of inner nuclear membrane PA homeostasis, including yeast Seipin, a known mediator of nuclear lipid droplet biogenesis. Here, we show that Seipin preserves nuclear envelope integrity by preventing its deformation and ectopic membrane formation. Mutations of specific regions of Seipin, some linked to human lipodystrophy, disrupt PA distribution at the inner nuclear membrane and nuclear lipid droplet formation. Investigating the Seipin co-factor Ldb16 reveals that a triacylglycerol binding site is crucial for lipid droplet formation, whereas PA regulation can be functionally separated. Our study highlights the potential of lipid biosensor screens for examining inner nuclear membrane lipid metabolism.

IFN-γ-dependent regulation of intestinal epithelial homeostasis by NKT cells

Intestinal homeostasis is maintained through the combined functions of epithelial and immune cells that collaborate to preserve the integrity of the intestinal barrier. However, the mechanisms by which immune cell populations regulate intestinal epithelial cell (IEC) homeostasis remain unclear. Here, we use a multi-omics approach to study the immune-epithelial crosstalk and identify CD1d-restricted natural killer T (NKT) cells as key regulators of IEC biology. We find that NKT cells are abundant in the proximal small intestine and show hallmarks of activation at steady state. Subsequently, NKT cells regulate the survival and the transcriptional and cellular composition landscapes of IECs in intestinal organoids, through interferon-γ (IFN-γ) and interleukin-4 secretion. Invivo, lack of NKT cells results in an increase in IEC turnover, while NKT cell activation leads to IFN-γ-dependent epithelial apoptosis. Our findings propose NKT cells as potent producers of cytokines that contribute to the regulation of IEC homeostasis.

Spinal AT1R contributes to neuroinflammation and neuropathic pain via NOX2-dependent redox signaling in microglia

Microglia-mediated neuroinflammation demonstrates a crucial act in the progression of neuropathic pain. Oxidative damage induced by reactive oxygen species (ROS) derived from NADPH oxidase (NOX) in microglia drives proinflammatory microglia activation. Recent evidence points to the central renin angiotensin system (RAS) is involved in oxidative stress and neuroinflammation, with the angiotensin converting enzyme/angiotensin II/angiotensin receptor-1 (ACE/Ang II/AT1R) axis promoting inflammation through increased ROS production, counteracted by the ACE2/Ang (1-7)/ Mas receptor (MasR) axis. While interventions targeting spinal AT1R have been shown to alleviate nociceptive hypersensitivity; yet the mechanisms remain elusive. Here, we discovered that spared nerve injury (SNI)-induced mechanical allodynia in rats were associated with M1-like microglia activation, oxidative stress and overactivity of ACE/Ang II/AT1R axis in the spinal cord. Increased AT1R and NOX2 expression were observed in activated dorsal horn microglia following SNI. Blockade of AT1R with losartan potassium (LOP) suppressed NOX2-mediated oxidative stress, and promoted a shift in microglia from the proinflammatory M1 phenotype to the anti-inflammatory M2 phenotype in LPS-treated BV-2 cells. Additionally, NOX2 overexpression triggered the activation of the high-mobility group box 1/ nuclear factor-kappa B (HMGB1/NF-κB) signaling pathway. Intrathecal administration of LOP effectively inhibited SNI-induced NOX2 overactivation in microglia and suppressed the HMGB1/NF-kB pathway, reducing oxidative stress and shifting the microglia polarization from M1 to M2 in the spinal cord, thereby attenuating neuroinflammation and pain hypersensitivity. Collectively, these findings underscore the neuroimmune-modulating effects of spinal AT1R in neuropathic pain, highlighting the regulation of redox homeostasis in microglia via a NOX2 dependent mechanism.

Expression of PPAR-γ TF by newly synthesized thiazolidine-2,4-diones to manage glycemic control: Insights from in silico, in vitro and experimental pharmacology in wistar rats.

In pursuit of novel antidiabetic agents to combat type II diabetes mellitus, our study focused on identifying pharmacophoric features responsible for PPAR-γ expression, a key regulator of glucose homeostasis and lipid metabolism. This goal was achieved through pharmacophore model generation and screening of rationally designed library of thiazolidine-2,4-dione hybrids (7a-7f). The top hits were synthesized, characterized, and evaluated for their in vitro and in vivo antidiabetic activities. Among these, compounds 7b and 7c emerged as promising candidates, exhibiting significant in vitro inhibitory activity against human pancreatic α-amylase (HPA) and human liver α-glucosidase (HLAG) enzymes, along with enhanced glucose uptake in L6 myotube cell lines. Specifically, compound 7b showed 29.04±1.13µM HPA inhibition, 34.21±1.16µg/mL HLAG inhibition, and 77.12±1.02% glucose uptake, while compound 7c displayed 28.35±1.01µM HPA inhibition, 26.21±1.17µM HLAG inhibition, and 78.54±0.54% glucose uptake. Mechanistic studies revealed a dose-dependent increase in PPAR-γ transcription factor expression, supported by molecular docking that showed favorable interactions with key residues TYR473, SER289, and HIE323. Molecular dynamics simulations confirmed the stability of these interactions, and MM/GBSA binding free energy calculations indicated potential for further optimization. In vivo studies in STZ-induced diabetic Wistar rats demonstrated significant improvements in glucose homeostasis, insulin sensitivity, and lipid metabolism, with a notable decrease in triglycerides and VLDL levels. Compound 7c also showed an improved pharmacokinetic profile with a half-life of 4.01h and an elimination rate constant of 0.325, compared to compound 7b. Both compounds enhanced glycogen content and antioxidant biomarkers, with a high safety profile (LD50 of 500mg/kg). Overall, compound 7c stands out as a promising lead for further development, with compound 7b also showing strong potential, providing valuable insights for future antidiabetic drug development efforts.

The ALS-associated co-chaperone DNAJC7 mediates neuroprotection against proteotoxic stress by modulating HSF1 activity.

The degeneration of neurons in patients with amyotrophic lateral sclerosis (ALS) is commonly associated with accumulation of misfolded, insoluble proteins. Heat shock proteins (HSPs) are central regulators of protein homeostasis as they fold newly synthesized proteins and refold damaged proteins. Heterozygous loss-of- function mutations in the DNAJC7 gene that encodes an HSP co-chaperone were recently identified as a cause for rare forms of ALS, yet the mechanisms underlying pathogenesis remain unclear. Using mass spectrometry, we found that the DNAJC7 interactome in human motor neurons (MNs) is enriched for RNA binding proteins (RBPs) and stress response chaperones. MNs generated from iPSCs with the ALS-associated mutation R156X in DNAJC7 exhibit increased insolubility of its client RBP HNRNPU and associated RNA metabolism alterations. Additionally, DNAJC7 haploinsufficiency renders MNs increasingly susceptible to proteotoxic stress and cell death as a result of an ablated HSF1 stress response pathway. Critically, expression of HSF1 in mutant DNAJC7 MNs is sufficient to rescue their sensitivity to proteotoxic stress, while postmortem ALS patient cortical neurons exhibit a reduction in the expression of HSF1 pathway genes. Taken together, our work identifies DNAJC7 as a crucial mediator of HNRNPU function and stress response pathways in human MNs and highlights HSF1 as a therapeutic target in ALS.

Disruption of local circadian clocks in aristolochic acid-induced nephropathy in mice

BackgroundAristolochic acid I (AAI), an emerging biogenic contaminant widely present in Aristolochic plants, has been implicated in the progression of tubulointerstitial disease, known as aristolochic acid nephropathy (AAN). The circadian clock, a vital regulator of organ homeostasis, is susceptible to external chemical cues, including toxins. However, the reciprocal interactions between AAI and the circadian clock remain unexplored. MethodsWe initially assessed sex- and time-dependent nephropathy and behavioral responses in C57BL/6J mice exposed to AAI. Subsequently, we evaluated changes in the expression of circadian clock genes following treatment with AAI or its bioactive metabolite, aristolactam I, using real-time quantitative PCR and immunoblotting in renal tissues and cells. Additionally, real-time reporter assays were conducted on kidney explants from PER2::Luc knock-in reporter mice and Per2-dLuc/Bmal1-dLuc reporter cell lines. To further elucidate the regulatory role of circadian clocks in AAI-induced nephropathy, mice with global or kidney-specific knockout of Bmal1, as well as mice subjected to experimental jetlag, were utilized. ResultsOur findings revealed a sex-dependent nephrotoxicity of AAI, with males exhibiting greater vulnerability. AAI-induced nephropathy was accompanied by impaired spatial cognitive function, disruptions in free-running locomotor activity, altered renal expression of multiple core clock genes, and disturbances in the circadian rhythm of renal PER2::Luc activity. Notably, kidney-specific ablation of the core clock gene Bmal1 significantly exacerbated renal injury and inflammation, whereas disruptions to the central clock, either genetically (through conventional knockout of Bmal1) or environmentally (mimicking jetlag), had minimal effects on AAI nephrotoxicity. Furthermore, both AAI and its bioactive metabolite aristolactam I demonstrated the ability to disrupt circadian clocks in human osteosarcoma cells (U2OS) and mouse renal tubular epithelial cells (mRTEC). ConclusionCollectively, these findings highlight the detrimental impact of aristolochic acids on local renal circadian clocks, ultimately exacerbating kidney damage. This study provides novel insights into the molecular mechanisms underlying AAI nephrotoxicity, potentially opening avenues for therapeutic interventions aimed at modulating the renal circadian clock to treat AAN.

The impact of sodium selenite and seleno-L-methionine on stress erythropoiesis in a murine model of hemolytic anemia

BackgroundSelenium (Se) is an essential trace element that exerts most biological activities through selenoproteins. Dietary selenium (Se) is a key regulator of red cell homeostasis and stress erythropoiesis. However, it is unknown if the form and increasing doses of Se supplementation in the diet impacts stress erythropoiesis under anemic conditions. ObjectiveIf inorganic (sodium selenite; Na2SeO3) or organic (seleno-L-methionine, Se-Met) forms of Se within different concentrations (deficient, adequate, supplemented, and supranutritional) support stress erythropoiesis in anemic mice. MethodsThree-week-old male C57BL/6 mice were subjected to graded levels of Se in the form of <0.01 ppm Se (Se-deficiency; Se-D), 0.1ppm Na2SeO3 (adequacy), 0.4ppm Na2SeO3 (supplemented), 3ppm Na2SeO3 (supranutritional), 0.4ppm Se-Met (supplemented), or 3ppm Se-Met (supranutritional), for 10-12 weeks prior to intra-peritoneal phenylhydrazine (PHZ) administration to induce hemolytic anemia. Following three days post-PHZ injection, spleen and blood samples were used to assess the impact of form and graded levels of Se in the diet on stress erythropoiesis. ResultsPhenotypic parameters showed that supplementing the diet with Se in the form of Na2SeO3 or Se-Met alleviated hemolytic anemia and promoted stress erythropoiesis by supporting the formation of erythroblastic islands (EBIs). Se-Met at 0.4 ppm enhanced erythroid progenitor differentiation, while Na2SeO3 at 0.4 ppm and 3 ppm aided monocyte recruitment and macrophage differentiation within EBIs. Additionally, 3 ppm Se-Met triggered a stronger inflammatory response than the same dose of Na2SeO3. ConclusionsWhile both Se-Met and Na2SeO3 effectively aided in stress erythropoiesis, Na2SeO3 supplementation effectively supported stress erythropoiesis with a minimal inflammatory response, while Se-Met at supranutritional dosage led to increased inflammation despite its support for stress erythropoiesis. These results indicate diverse mechanisms of action of Se on the alleviation of anemia by stress erythropoiesis, which should be considered for further studies to complement existing therapies.

Chemogenetic engagement of different GPCR signaling pathways segregates the orexigenic activity from the control of whole-body glucose metabolism by AGRP Neurons.

BackgroundThe control of energy balance involves neural circuits in the central nervous system, including AGRP neurons in the arcuate nucleus of the hypothalamus (ARC). AGRP neurons are crucial for energy balance and their increased activity during fasting is critical to promote feeding behavior. The activity of these neurons is influenced by multiple signals including those acting on G-protein coupled receptors (GPCR) activating different intracellular signaling pathways. We sought to determine whether discrete G-protein mediated signaling in AGRP neurons, promotes differential regulation of feeding and whole-body glucose homeostasis. Methodology: To test the contribution of Gαq/11 or Gαs signaling, we developed congenital mouse lines expressing the different DREADD receptors (i.e., hM3q and rM3s), in AGRP neurons. Then we elicited chemogenetic activation of AGRP neurons in these mice during the postprandial state to determine the impact on feeding and glucose homeostasis. ResultsActivation of AGRP neurons via hM3q and rM3s promoted hyperphagia. In contrast, only hM3q activation of AGRP neurons of the hypothalamic arcuate nucleus during the postprandial state enhanced whole-body glucose disposal by reducing sympathetic nervous system activity to the pancreas and liver, promoting glucose-stimulated insulin secretion, glycogen deposition and improving glucose tolerance. ConclusionThese data indicate that AGRP neurons regulate food intake and glucose homeostasis through distinct GPCR-dependent signaling pathways and suggest that the transient increase in AGRP neuron activity may contribute to the beneficial effects of fasting on glycemic control.

Endothelial Cell Aging and Autophagy Dysregulation.

Entropy is a natural process that affects all living cells, including senescence, an irreversible physiological process that impairs cell homeostasis. Age is a significant factor in disease development, and the pathogenesis of endothelial cell aging is multifactorial. Autophagy dysfunction accelerates endothelial cell aging and cell death, while autophagy preserves endothelial cell youthfulness through intracellular homeostasis and gene expression regulation. Sirt, mTORC1, and AMPK are youthfulness genes that induce autophagy by inhibiting mTOR and upregulating FIP200/Atg13/ULK1. Aged endothelial cells have decreased levels of Lamin B1, γH2AX, Ki67, BrdU, PCNA, and SA β-Gal. Maintaining healthy young endothelial cells can prevent most cardiovascular diseases. Autophagy targeting is a potential future therapeutic strategy to modify endothelial cell age and potentially slow or reverse the aging process. This article provides state-of-the-art research on the role of autophagy in endothelial cell aging. Hypothesizing that autophagy dysregulation is associated with early endothelial cell dysfunction and further clinical sequelae, including atherosclerosis formation, leading to various cardiovascular diseases.

Distribution of the p66Shc Adaptor Protein Among Mitochondrial and Mitochondria-Associated Membranes Fractions in Normal and Oxidative Stress Conditions.

p66Shc is an adaptor protein and one of the cellular fate regulators since it modulates mitogenic signaling pathways, mitochondrial function, and reactive oxygen species (ROS) production. p66Shc is localized mostly in the cytosol and endoplasmic reticulum (ER); however, under oxidative stress, p66Shc is post-translationally modified and relocates to mitochondria. p66Shc was found in the intermembrane space, where it interacts with cytochrome c, contributing to the hydrogen peroxide generation by the mitochondrial respiratory chain. Our previous studies suggested that p66Shc is localized also in mitochondria-associated membranes (MAM). MAM fraction consists of mitochondria and mostly ER membranes. Contact sites between ER and mitochondria host proteins involved in multiple processes including calcium homeostasis, apoptosis, and autophagy regulation. Thus, p66Shc in MAM could participate in processes related to cell fate determination. Due to reports on various and conditional p66Shc intracellular localization, in the present paper, we describe the allocation of p66Shc pools in different subcellular compartments in mouse liver tissue and HepG2 cell culture. We provide additional evidence for p66Shc localization in MAM. In the present study, we use precisely purified subcellular fraction isolated by differential centrifugation-based protocol from control mouse liver tissue and HepG2 cells and from cells treated with hydrogen peroxide to promote mitochondrial p66Shc translocation. We performed controlled digestion of crude mitochondrial fraction, in which the degradation patterns of p66Shc and MAM fraction marker proteins were comparable. Moreover, we assessed the distribution of the individual ShcA isoforms (p46Shc, p52Shc, and p66Shc) in the subcellular fractions and their contribution to the total ShcA in control mice livers and HepG2 cells. In conclusion, we showed that a substantial pool of p66Shc protein resides in MAM in control conditions and after oxidative stress induction.

Identification of miR-141 as a Regulator of Epidermal Homeostasis

MicroRNAs (miRNAs), small endogenous non-coding RNAs, are involved in the regulation of epidermal homeostasis. Among them, miR-203 was the most described and expressed in human epidermis, promoting keratinocyte differentiation by repressing genes involved in proliferation. To identify other miRNAs involved in this process, the miRNomes of normal human keratinocytes cultured in monolayer (2D) or in 3D reconstructed skin were compared. Besides miR-203, miR-141 was one of the most expressed miRNAs in 3D culture and was overexpressed in 3D vs 2D condition, i.e. during keratinocyte differentiation. Functional experiments revealed that, mostly expressed in the basal layer, miR-141 decreased keratinocyte proliferation and clonogenicity, while promoting differentiation. Target prediction algorithm coupled with transcriptomic data of keratinocytes overexpressing miR-141, as well as 3'UTR luciferase assays enabled to evidence CCND2 mRNA as a direct target of miR-141, leading to its down-regulation by miR-141 overexpression. Finally, CCND2 silencing decreased keratinocyte proliferation and induced their differentiation, revealing that miR-141 action was mediated by CCND2. MiR-141 features were also compared with miR-203 in parallel experiments. Although miR-141 displayed similar functions to the ones of miR-203, it exhibited different localization and targets, suggesting a joint participation of miR-141 and miR-203 in engaging and maintaining keratinocyte towards differentiation, respectively.