Effect of Tempeh and Daidzein on Calcium Status, Calcium Transporters, and Bone Metabolism Biomarkers in Ovariectomized Rats.

Menopause marks a critical life stage characterized by hormonal changes that significantly impact bone health, leading to a heightened susceptibility to bone fractures. This research seeks to elucidate the impact of daidzein and tempeh on calcium status, calcium transporters, and bone metabolism in an ovariectomized rat model. Forty female Wistar rats, aged 3 months, participated in a two-phase experiment. The initial phase involved inducing a calcium deficit, while the second phase comprised dietary interventions across five groups: Sham (S) and Ovariectomy (O) with a standard diet, O with bisphosphonate (OB), O with pure daidzein (OD), and O with tempeh (OT). Multiple parameters, encompassing calcium levels, calcium transporters, bone histopathology, and serum bone metabolism markers, were evaluated. The findings revealed that the OT group showcased heightened levels of bone turnover markers, such as pyridinoline, C-telopeptide of type I collagen, bone alkaline phosphatase, and procollagen type I N-terminal propeptide, in contrast to S and O groups, with statistical significance (p < 0.05). Histopathologically, both the OD and OT groups exhibited effects akin to the OB group, indicating a decrease in the surface area occupied by adipocytes in the femoral bone structure, although statistically non-equivalent, supporting the directionally similar trends. Although TRPV5 and TRPV6 mRNA expression levels in the jejunum and duodenum did not display statistically significant differences (p > 0.05), the OD and OT groups exhibited increased expression compared to the O group. We hypothesized that obtained results may be related to the effect of isoflavones on estrogen pathways because of their structurally similar to endogenous estrogen and weak estrogenic properties. In conclusion, the daily consumption of pure daidzein and tempeh could potentially improve and reinstate calcium status, calcium transport, and bone metabolism in ovariectomized rats. Additionally, isoflavone products demonstrate effects similar to bisphosphonate drugs on these parameters in ovariectomized rats.

GIP_HUMAN [22-51] Peptide Encoded by the Glucose-Dependent Insulinotropic Polypeptide (GIP) Gene Suppresses Insulin Expression and Secretion in INS-1E Cells and Rat Pancreatic Islets.

GIP_HUMAN [22-51] is a recently discovered peptide that shares the same precursor molecule with glucose-dependent insulinotropic polypeptide (GIP). In vivo, chronic infusion of GIP_HUMAN [22-51] in ApoE-/- mice enhanced the development of aortic atherosclerotic lesions and upregulated inflammatory and proatherogenic proteins. In the present study, we evaluate the effects of GIP_HUMAN [22-51] on insulin mRNA expression and secretion in insulin-producing INS-1E cells and isolated rat pancreatic islets. Furthermore, we characterize the influence of GIP_HUMAN [22-51] on cell proliferation and death and on Nf-kB nuclear translocation. Rat insulin-producing INS-1E cells and pancreatic islets, isolated from male Wistar rats, were used in this study. Gene expression was evaluated using real-time PCR. Cell proliferation was studied using a BrdU incorporation assay. Cell death was quantified by evaluating histone-complexed DNA fragments. Insulin secretion was determined using an ELISA test. Nf-kB nuclear translocation was detected using immunofluorescence. GIP_HUMAN [22-51] suppressed insulin (Ins1 and Ins2) in INS-1E cells and pancreatic islets. Moreover, GIP_HUMAN [22-51] promoted the translocation of NF-κB from cytoplasm to the nucleus. In the presence of a pharmacological inhibitor of NF-κB, GIP_HUMAN [22-51] was unable to suppress Ins2 mRNA expression. Moreover, GIP_HUMAN [22-51] downregulated insulin secretion at low (2.8 mmol/L) but not high (16.7 mmol/L) glucose concentration. By contrast, GIP_HUMAN [22-51] failed to affect cell proliferation and apoptosis. We conclude that GIP_HUMAN [22-51] suppresses insulin expression and secretion in pancreatic ß cells without affecting ß cell proliferation or apoptosis. Notably, the effects of GIP_HUMAN [22-51] on insulin secretion are glucose-dependent.

Effects of isoflavone and probiotic intake on calcium transport and bone metabolism biomarkers in female rats.

Calcium is essential for maintaining bone health as it contributes to bone formation, remodeling, strength, and density. This study investigated the effect of isoflavones and probiotics on calcium transporters' gene expression, serum calcium levels, and bone metabolism biomarkers in healthy female rats. Forty-eight female Wistar rats were classified into six groups. Bone metabolism biomarkers (pyridinoline, deoxypyridinoline, parathyroid hormone, and osteocalcin) and serum calcium levels were measured by enzyme-linked immunosorbent assay (ELISA) and atomic absorption spectroscopy (AAS), respectively. Gene expression of calcium transporters (Trpv5 and Trpv6) was evaluated in duodenum and jejunum tissue samples using quantitative polymerase chain reaction (qPCR). Trpv5 and Trpv6, epithelial calcium channels, play a crucial role in calcium transport and homeostasis in the body. The study consisted of a1-week adaptation period for the rats to adjust to the controlled conditions, followed by an 8-week intervention phase. The daidzein and genistein group showed a significant increase in the gene expression of the Trpv6 transporter in the duodenum and a marked decrease in serum pyridinoline levels compared to the control group. The tempeh and soybean groups showed a significant decrease in the gene expression of the Trpv5 calcium transporter in the jejunum. However, no significant influence of the Lactobacillus acidophilus diet on calcium transport and bone metabolism biomarkers was observed in the L. acidophilus group. The correlation analysis showed a significant positive relationship between serum calcium, bone metabolism biomarkers, and calcium transporters. In conclusion, our study demonstrates that the daidzein and genistein diet improves calcium transport in the duodenum and reduces pyridinoline serum concentrations, while tempeh and soybean diets reduce calcium transport in the jejunum. However, the combination of daidzein, genistein, and L. acidophilus did not demonstrate a synergistic effect on calcium transport and bone metabolism, suggesting that further investigations are needed to elucidate their potential interactions.

Cord Blood Spexin Level in Mothers with Obesity-Forecast of Future Obesity?

Spexin (SPX) is a peptide that plays an important role in the regulation of food intake and body weight (BW) by the effect on carbohydrate-lipid metabolism. However, the role of SPX in fetal life, in children, and in adolescent metabolism is limited. Therefore, we decided to check whether obesity affects the concentration of SPX in the mother's peripheral blood (MB) and umbilical cord blood (UCB). Using MB and UCB sera on the day of delivery obtained from 48 women (24 non-obese and 24 obese) and commercially available Elisa kits and colorimetric assays, we determined changes in SPX and the relationship between SPX concentration and other metabolic and anthropometric markers (body weight and BMI) on the day of delivery and in children at the age of 36 months. We found lower concentrations of SPX in MB (p < 0.05) and UCB (p < 0.01) derived from obese women (BMI > 30) and a moderate linear correlation (r = 0.4429; p < 0.01) between SPX concentrations in MB and UCB. We also noted that the concentration of SPX is not correlated with the child's body weight on the day of birth (r = -0.0128). However, there is a relationship between SPX at birth and body weight at 3 years of age (r = -0.3219; p < 0.05). Based on the obtained results, it can be assumed that spexin is one of the factors modulating the child's metabolism already in the fetal period and can be considered a potential marker of future predisposition to obesity. However, confirmation of this thesis requires additional research.

Sex-specific cytotoxicity of ostarine in cardiomyocytes.

Ostarine is the most popular compound in the selective androgen receptor modulator group (SARMs). Ostarine is used as a physical performance-enhancing agent. The abuse of this agent in higher doses may lead to severe side effects. Here, we evaluate the effects of ostarine on the heart. We utilized a cardiomyocyte H9C2 cell line, isolated primary female and male cardiac fibroblast cells, as well as hearts obtained from rats. Ostarine increased the accumulation of two fibrosis protein markers, αSMA and fibronectin (p < 00.1) in male, but not in female fibroblast cells. Ostarine increased the expression of the cardiomyopathy marker ßMhc in the H9C2 cell line (p < 0.05) and in the heart in rats (p < 0.01). The unfavorable changes were observed at high ostarine doses. Moreover, a decrease in viability and an increase in cytotoxicity marker LDH were observed already at lowest dose (1 nmoL/l). Taken together, our results suggest that ostarine is cardiotoxic which may be more relevant in males than in females.

Special Issue: Lipid Metabolism, Adipogenesis and Fat Tissue Metabolism: Gene Regulation.

Lipid metabolism is pivotal in controlling energy homeostasis [...].

The Effects of Neuropeptide B on Proliferation and Differentiation of Porcine White Preadipocytes into Mature Adipocytes.

Neuropeptide B (NPB) affects energy homeostasis and metabolism by binding and activating NPBWR1 and NPBWR2 in humans and pigs. Recently, we reported that NPB promotes the adipogenesis of rat white and brown preadipocytes as well as 3T3-L1 cells. In the present study, we evaluated the effects of NPB on the proliferation and differentiation of white porcine preadipocytes into mature adipocytes. We identified the presence of NPB, NPBWR1, and NPBWR2 on the mRNA and protein levels in porcine white preadipocytes. During the differentiation process, NPB increased the mRNA expression of PPARγ, C/EBPß, C/EBPα, PPARγ, and C/EBPß protein production in porcine preadipocytes. Furthermore, NPB stimulated lipid accumulation in porcine preadipocytes. Moreover, NPB promoted the phosphorylation of the p38 kinase in porcine preadipocytes, but failed to induce ERK1/2 phosphorylation. NPB failed to stimulate the expression of C/EBPß in the presence of the p38 inhibitor. Taken together, we report that NPB promotes the differentiation of porcine preadipocytes via a p38-dependent mechanism.

Daily Treatment of Mice with Type 2 Diabetes with Adropin for Four Weeks Improves Glucolipid Profile, Reduces Hepatic Lipid Content and Restores Elevated Hepatic Enzymes in Serum.

Adropin is a peptide hormone encoded by Energy Homeostasis Associated gene. Adropin modulates energy homeostasis and metabolism of lipids and carbohydrates. There is growing evidence demonstrating that adropin enhances insulin sensitivity and lowers hyperlipidemia in obese mice. The aim of this study was to investigate the effects of daily administration of adropin for four weeks in mice with experimentally induced type 2 diabetes (T2D). Adropin improved glucose control without modulating insulin sensitivity. Adropin reduced body weight, size of adipocytes, blood levels of triacylglycerol and cholesterol in T2D mice. T2D mice treated with adropin had lower liver mass, reduced hepatic content of triacylglycerol and cholesterol. Furthermore, adropin attenuated elevated blood levels of hepatic enzymes (ALT, AST, GGT and ALP) in T2D mice. In T2D mice, adropin increased the circulating adiponectin level. Adropin had no effects on circulating insulin and glucagon levels and did not alter pancreatic islets morphology. These results suggest that adropin improves glucose control, lipid metabolism and liver functions in T2D. In conjunction with reduced lipid content in hepatocytes, these results render adropin as an interesting candidate in therapy of T2D.

Ostarine-Induced Myogenic Differentiation in C2C12, L6, and Rat Muscles.

Ostarine (also known as enobosarm or Gtx-024) belongs to the selective androgen receptor modulators (SARMs). It is a substance with an aryl-propionamide structure, classified as a non-steroidal compound that is not subjected to the typical steroid transformations of aromatization and reduction by α5 reductase. Despite ongoing research on ostarine, knowledge about it is still limited. Earlier studies indicated that ostarine may affect the metabolism of muscle tissue, but this mechanism has not been yet described. We aimed to investigate the effect of ostarine on the differentiation and metabolism of muscle. Using C2C12 and L6 cells, as well as muscles obtained from rats administered ostarine, we showed that ostarine stimulates C2C12 and L6 proliferation and cell viability and that this effect is mediated by androgen receptor (AR) and ERK1/2 kinase activation (p < 0.01). We also found that ostarine stimulates muscle cell differentiation by increasing myogenin, MyoD, and MyH expression in both types of cells (p < 0.01). Moreover, pharmacological blocking of AR inhibits the stimulatory effect of ostarine. We further demonstrated that 30 days of ostarine administration increases myogenin, MyoD, and MyH expression, as well as muscle mass, in rats (p < 0.01). Based on our research, we conclude that ostarine stimulates muscle tissue proliferation and differentiation via the androgen receptor.

Changes in metabolic and hormonal profiles during transition period in dairy cattle - the role of spexin.

BACKGROUND: This study aimed to evaluate spexin as a novel blood marker and to describe the relationship of this peptide with selected biochemical metabolites measured during the transition period in dairy cows. Additionally, mRNA expression of the spexin gene as well as spexin receptors - galanin receptor type 2 and galanin receptor type 3, was investigated in several bovine tissues. Blood samples were collected at weekly intervals starting at 21 days before the estimated parturition day until 21 days in milk to determine concentrations of spexin, nonesterified fatty acids, ß-hydroxybutyrate acid, total and active ghrelin, progesterone, glucose, insulin, IGF-I, triglycerides, cholesterol, leptin, corticosterone and 17-ß-estradiol as well as the activity of aspartate transaminase, alkaline phosphatase and gamma-glutamyl transferase. RESULTS: Spexin concentration decreased from 21 d before parturition to calving day and next it rose during the first 14 d of lactation. The lowest concentration of spexin was recorded on the calving day and it differed from the mean level of this peptide before parturition as well as postpartum. Moreover, differences were observed between mean spexin concentrations before and after calving. Spexin levels were moderately negatively correlated with NEFA (r = - 0.39) and total ghrelin contents (r = - 0.41), weakly correlated with BHBA (r = - 0.35) while they showed a moderate positive relationship with progesterone concentrations (r = 0.42). Moreover, we detected that mRNA expression of GALR2, GALR3 and SPX is present in various bovine tissues (kidney, bowel, rumen, spinal cord, lung, skeletal muscle, liver, heart, fat and spleen). CONCLUSION: A negative correlation between spexin concentration and NEFA, BHBA and total ghrelin contents as well as a positive relationship with levels of progesterone, metabolites and hormones, which are key players in the dairy cow transition period, may confirm an important function of this peptide in metabolism regulation. Thus measurement of spexin concentration could provide useful supplementary information for dairy cow herd health monitoring.

Changes in MOTS-c Level in the Blood of Pregnant Women with Metabolic Disorders.

MOTS-c peptide is a member of the group of mitochondria-derived peptides (MDP). It is a product of the open reading frame in the 12S RNA gene. Due to its features and functions in the body, this peptide is classified as a hormone. The first publications indicated that this hormone improves insulin sensitivity and lowers body weight in obese animals. This suggests that it may be an important peptide in maintaining the body's energy homeostasis. The aim of our work was to investigate the potential role of MOTS-c peptide during pregnancy, which is a condition prone to metabolic disorders. The research covered healthy, obese women and women with thyroid disorders. The obtained results indicated an increase in the concentration of MOTS-c in the blood of mothers and newborns in the obese group as compared to the healthy control group and a corresponding decrease in the concentration of this peptide in mothers and newborns in the group with hypothyroidism compared to the obese group. Moreover, we also observed a strong positive correlation between the concentration of MOTS-c in maternal blood and in umbilical cord blood. In summary, the MOTS-c peptide shows changes in blood concentration in various physiological states and may, in the future, become an important tool in the fight against metabolic diseases such as obesity or type 2 diabetes.

30-Day spexin treatment of mice with diet-induced obesity (DIO) and type 2 diabetes (T2DM) increases insulin sensitivity, improves liver functions and metabolic status.

Spexin (SPX) is a 14 aa peptide discovered in 2007 using bioinformatics methods. SPX inhibits food intake and regulates lipid, and carbohydrate metabolism. Here, we evaluate the ability of SPX at improving metabolic control and liver function in obese and type 2 diabetic animals. The effects of 30 days SPX treatment of mice with experimentally induced obesity (DIO) or type 2 diabetes (T2DM) on serum glucose and lipid levels, insulin sensitivity and hormonal profile (insulin, glucagon, adiponectin, leptin, TNF alpha, IL-6 and IL-1ß) are characterized. In addition, alterations of hepatic lipid and glycogen contents are evaluated. We report that SPX decreases body weight in healthy and DIO mice, and reduces lipid content in all three animal groups. SPX improves insulin sensitivity in DIO and T2DM animals. In addition, SPX modulates hormonal and metabolic profile by regulating the concentration of adiponectin (concentration increase) and leptin (concentration decrease) in the serum blood of DIO and T2DM mice. Lastly, SPX decreases lipid content as well as IL-6 and TNF-α protein levels in liver of DIO and T2DM mice, and reduces IL-6 and TNF-alpha concentrations in the serum derived from T2DM mice. Based on our results, we conclude that SPX could be involved in the development of obesity and type 2 diabetes mellitus and it can be further evaluated as a potential target for therapy of DIO and T2DM.

The Role of Peptide Hormones Discovered in the 21st Century in the Regulation of Adipose Tissue Functions.

Peptide hormones play a prominent role in controlling energy homeostasis and metabolism. They have been implicated in controlling appetite, the function of the gastrointestinal and cardiovascular systems, energy expenditure, and reproduction. Furthermore, there is growing evidence indicating that peptide hormones and their receptors contribute to energy homeostasis regulation by interacting with white and brown adipose tissue. In this article, we review and discuss the literature addressing the role of selected peptide hormones discovered in the 21st century (adropin, apelin, elabela, irisin, kisspeptin, MOTS-c, phoenixin, spexin, and neuropeptides B and W) in controlling white and brown adipogenesis. Furthermore, we elaborate how these hormones control adipose tissue functions in vitro and in vivo.

Effects of silybin supplementation on nutrient digestibility, hematological parameters, liver function indices, and liver-specific mi-RNA concentration in dogs.

BACKGROUND: Hepatopathies are an important group of disorders in dogs where proper nutritional care is crucial. Supplementation with a hepatoprotectant like silybin can improve liver function and should not interfere with nutrient digestibility. The purpose of this study was to investigate the effect of both pure silybin and commercial hepatoprotectant on nutrients digestibility, liver function indices and health status in healthy dogs (EXP1). Moreover, the second experiment (EXP2) investigated the effect of commercial hepatoprotectant on liver function tests and liver-associated miRNAs concentration in dogs with idiopathic liver disorder. RESULTS: Nutrient digestibility was not affected by treatment in EXP1. Supplementation did alter the serum fatty acid profile, with no clinical relevance. The levels of liver markers such as ALT, AST and GGT significantly decreased. In EXP2, supplementation with commercial hepatoprotectant containing silybin improved liver function tests. A decrease was observed in liver serum markers such as ALT, AST and miR122 concentration. CONCLUSIONS: EXP1 confirmed that silybin (whether pure or as a commercial hepatoprotectant) does not interfere with digestion which subsequently exerts no detrimental effect on dogs' health and metabolism. In EXP2, dietary supplementation with commercial hepatoprotectant containing silybin resulted in a decreased activity of serum liver markers, accompanied by a decrease in the concentration of liver-specific miRNA molecules. Liver function indices were consequently improved. Silybin supplementation can thus serve as an effective therapeutical tool in dogs with hepatopathies.

The Long-Term Effects of High-Fat and High-Protein Diets on the Metabolic and Endocrine Activity of Adipocytes in Rats.

The increasing prevalence of overweight and obesity and the rising awareness of their negative consequences are forcing researchers to take a new view of nutrition and its consequences for the metabolism of whole organisms as well as the metabolism of their individual systems and cells. Despite studies on nutrition having been carried out for a few decades, not many of them have focused on the impacts of these diets on changes in the metabolism and endocrine functions of isolated adipocytes. Therefore, we decided to investigate the effects of the long-term use (60 and 120 days) of a high-fat diet (HFD) and of a high-protein diet (HPD) on basic metabolic processes in fat cells-lipogenesis, lipolysis, and glucose uptake-and endocrine function, which was determined according to the secretion of adipokines into the incubation medium. Our results proved that the HPD diet improved insulin sensitivity, increased the intracellular uptake of glucose (p < 0.01) and its incorporation into lipids (p < 0.01) and modulated the endocrine function of these cells (decreasing leptin secretion; p < 0.01). The levels of biochemical parameters in the serum blood also changed in the HPD-fed rats. The effects of the HFD were inverse, as expected. We observed a decrease in adiponectin secretion and a diminished rate of lipogenesis (p < 0.01). Simultaneously, the secretion of leptin and resistin (p < 0.01) from isolated adipocytes increased. In conclusion, we noted that the long-term use of HPD and HFD diets modulates the metabolism and endocrine functions of isolated rat adipocytes. We summarize that an HFD had a negative effect on fat tissue functioning, whereas an HPD had positive results, such as increased insulin sensitivity and an improved metabolism of glucose and lipids in fat tissue. Moreover, we noticed that negative metabolic changes are reflected more rapidly in isolated cells than in the metabolism of the whole organism.

Effect of Fasting on the Spexin System in Broiler Chickens.

Spexin (SPX) is a highly conservative peptide hormone containing 14 amino acids and was discovered in 2007 by bioinformatics methods. However, nothing is yet known about its role in the metabolism of birds, including broilers. The aim of this study was to investigate the effect of short-term fasting (2, 4, and 8 h) on the concentration of SPX in blood serum and the expression levels of the genes encoding this peptide (SPX1) and its receptors, GALR2 and GALR3, in the tissues involved in carbohydrate and lipid metabolism (muscles, adipose tissue, and liver). We also analyzed the mRNA expression of these genes in various chicken tissues. Moreover, we studied the correlation between the serum level of SPX and other metabolic parameters (insulin, glucagon, glucose, triglycerides, and cholesterol). Using RT-qPCR, we found that SPX1, GALR2, and GALR3 are expressed in all investigated tissues in broiler chicken. Moreover, using a commercially available radio-immunoassay, we noted an increase of the SPX level in blood serum after 4 and 8 h of fasting compared to nonfasted animals (p < 0.05). This increase was positively correlated with glucagon concentration (r = 0.341; p < 0.05) and negatively with glucose concentration (r = -0.484; p < 0.01). Additionally, we discovered that in the short term, food deprivation leads to the expression regulation of SPX1, GALR2, and GLAR3 in tissues associated with metabolism of carbohydrates and lipids. The obtained results indicate that SPX is involved in the regulation of metabolism in broiler chickens.

Transcriptome Changes in Three Brain Regions during Chronic Lithium Administration in the Rat Models of Mania and Depression.

Lithium has been the most important mood stabilizer used for the treatment of bipolar disorder and prophylaxis of manic and depressive episodes. Despite long use in clinical practice, the exact molecular mechanisms of lithium are still not well identified. Previous experimental studies produced inconsistent results due to different duration of lithium treatment and using animals without manic-like or depressive-like symptoms. Therefore, we aimed to analyze the gene expression profile in three brain regions (amygdala, frontal cortex and hippocampus) in the rat model of mania and depression during chronic lithium administration (2 and 4 weeks). Behavioral changes were verified by the forced swim test, open field test and elevated maze test. After the experiment, nucleic acid was extracted from the frontal cortex, hippocampus and amygdala. Gene expression profile was done using SurePrint G3 Rat Gene Expression whole transcriptome microarrays. Data were analyzed using Gene Spring 14.9 software. We found that chronic lithium treatment significantly influenced gene expression profile in both mania and depression models. In manic rats, chronic lithium treatment significantly influenced the expression of the genes enriched in olfactory and taste transduction pathway and long non-coding RNAs in all three brain regions. We report here for the first time that genes regulating olfactory and taste receptor pathways and long non-coding RNAs may be targeted by chronic lithium treatment in the animal model of mania.

Alteration of active and repressive histone marks during adipogenic differentiation of porcine mesenchymal stem cells.

A characteristic spatial distribution of the main chromatin fractions is observed in most mammalian cell nuclei, with euchromatin localized in the interior and heterochromatin at the nuclear periphery. It has been shown that interactions of heterochromatin with the nuclear lamina are necessary to establish this conventional architecture. Adipocytes are specific cells in which a reduction in lamin A/C expression is observed. We hypothesize that the loss of lamin A/C during adipogenic differentiation of mesenchymal stem cells (MSCs) may be associated with the reorganization of the main classes of chromatin in the nucleus. Thus, in this study, we examine the abundance and nuclear distribution of selected heterochromatin (H3K9me3, H3K27me3 and H4K20me3) and euchromatin (H4K8ac, H3K4me3 and H3K9ac) histone marks during in vitro adipogenesis, using the pig as a model organism. We found that not only did the expression of lamin A/C decrease in our differentiation system, but so did the expression of lamin B receptor (LBR). The level of two heterochromatin marks, H3K27me3 and H4K20me3, increased during differentiation, while no changes were observed for H3K9me3. The levels of two euchromatin histone marks, H4K8ac and H3K9ac, were significantly higher in adipocytes than in undifferentiated cells, while the level of H3K4me3 did not change significantly. The spatial distribution of all the examined histone marks altered during in vitro adipogenesis. H3K27me3 and H4K20me3 moved towards the nuclear periphery and H3K9me3 localized preferentially in the intermediate part of adipocyte nuclei. The euchromatin marks H3K9ac and H3K4me3 preferentially occupied the peripheral part of the adipocyte nuclei, while H4K8ac was more evenly distributed in the nuclei of undifferentiated and differentiated cells. Analysis of the nuclear distribution of repetitive sequences has shown their clustering and relocalization toward nuclear periphery during differentiation. Our study shows that dynamic changes in the abundance and nuclear distribution of active and repressive histone marks take place during adipocyte differentiation. Nuclear reorganization of heterochromatin histone marks may allow the maintenance of the nuclear morphology of the adipocytes, in which reduced expression of lamin A/C and LBR is observed.

Spexin Promotes the Proliferation and Differentiation of C2C12 Cells In Vitro-The Effect of Exercise on SPX and SPX Receptor Expression in Skeletal Muscle In Vivo.

SPX (spexin) and its receptors GalR2 and GalR3 (galanin receptor subtype 2 and galanin receptor subtype 3) play an important role in the regulation of lipid and carbohydrate metabolism in human and animal fat tissue. However, little is still known about the role of this peptide in the metabolism of muscle. The aim of this study was to determine the impact of SPX on the metabolism, proliferation and differentiation of the skeletal muscle cell line C2C12. Moreover, we determined the effect of exercise on the SPX transduction pathway in mice skeletal muscle. We found that increased SPX, acting via GalR2 and GalR3 receptors, and ERK1/2 phosphorylation stimulated the proliferation of C2C12 cells (p < 0.01). We also noted that SPX stimulated the differentiation of C2C12 by increasing mRNA and protein levels of differentiation markers Myh, myogenin and MyoD (p < 0.01). SPX consequently promoted myoblast fusion into the myotubule (p < 0.01). Moreover, we found that, in the first stage (after 2 days) of myocyte differentiation, GalR2 and GalR3 were involved, whereas in the last stage (day six), the effect of SPX was mediated by the GalR3 isoform. We also noted that exercise stimulated SPX and GalR2 expression in mice skeletal muscle as well as an increase in SPX concentration in blood serum. These new insights may contribute to a better understanding of the role of SPX in the metabolism of skeletal muscle.

Effects of Ovariectomy and Sex Hormone Replacement on Numbers of Kisspeptin-, Neurokinin B- and Dynorphin A-immunoreactive Neurons in the Arcuate Nucleus of the Hypothalamus in Obese and Diabetic Rats.

KNDy neurons co-expressing kisspeptin (KP), neurokinin B (NKB) and dynorphin A (DYN A) in the arcuate nucleus of the hypothalamus (ARC) are key regulators of reproduction. Their activity is influenced by metabolic and hormonal signals. Previously, we have shown that orchidectomy alters the KP-, NKB-, and DYN A-immunoreactivity in the high-fat diet-induced (HFD) obesity and diabetes type 2 (DM2) models. Considering the potential sex difference in the response of KNDy neurons, we have hypothesized that ovariectomy (OVX) and post-ovariectomy replacement with estradiol (OVX+E2) or estradiol and progesterone (OVX+E2+P4) will also affect these neurons in HFD and DM2 females. Thus, each of these treatment protocols were employed for control, HFD, and DM2 groups of rats leading to nine experimental conditions within which we have determined the number of KP-, NKB-, or DYN-immunoreactive (-ir) neurons and assessed the metabolic and hormonal profiles of the animals. Accordingly: (1) no effects of group and surgery were observed on the number of KP-ir neurons; (2) the overall number of NKB-ir neurons was higher in the OVX+E2+P4 and OVX+E2 animals compared to OVX; (3) overall, the number of DYN A-ir neurons was higher in DM2 vs. control group, and surgery had an effect on the number of DYN A-ir neurons; (4) the metabolic and hormonal profiles were altered in HFD and DM2 animals compared to controls. Current data together with our previously published results indicate sex-specific differences in the response of KNDy neurons to DM2.