ABSTRACT
The COVID-19 pandemic caused by SARS-CoV-2 has presented numerous health challenges, including long-term COVID, which affects female reproductive health. This review consolidates the current research on the impact of SARS-CoV-2 on the menstrual cycle, ovarian function, fertility, and overall gynecological health. This study emphasizes the role of angiotensin-converting enzyme receptors in viral entry and the subsequent tissue-specific pathological effects. It also explores the potential influence of long COVID on hormonal balance and immune responses, contributing to menstrual irregularities and impaired ovarian function. The findings indicate a higher prevalence of long-term COVID-19 among women, highlighting the substantial implications for reproductive health and the need for sex-sensitive longitudinal studies. Enhanced surveillance and targeted research are essential to develop effective interventions that prioritize women's reproductive well-being following SARS-CoV-2 infection. This review advocates for a sex-informed approach to ongoing COVID-19 research and healthcare strategies, aiming to provide up-to-date and pertinent data for healthcare providers and the general public, ultimately improving outcomes for females affected by long COVID.
Subject(s)
COVID-19 , Reproductive Health , SARS-CoV-2 , Humans , Female , COVID-19/epidemiology , COVID-19/virology , COVID-19/immunology , Menstrual Cycle , Post-Acute COVID-19 Syndrome , FertilityABSTRACT
SCOPE: This study investigates the impact of extracts derived from Antarctic fish species, Trematomus newnesi and Trematomus bernacchii, on the migration of human placental trophoblast JEG-3 cells, which is a crucial aspect of successful pregnancy. METHODS AND RESULTS: The extracts, obtained from the muscles of these fish, significantly enhance the migration and invasion of JEG-3 cells in in vitro wound healing, Transwell, and collagen invasion assays. These effects are accompanied by an increase in matrix metalloproteinase (MMP) 9 activity, as demonstrated by zymography. Furthermore, the extracts activated Akt and protein phosphatase 1, resulting in the dephosphorylation of ß-catenin at Ser33/37/Thr41, as confirmed by western blot analysis. Consequently, MMP9 is upregulated, while metallopeptidase inhibitor 1/3 is downregulated, as verified by western blot and qRT-PCR analyses. Finally, utilizing ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis, followed by matching with the Global Natural Product Social Molecular Networking library, the study annotates the compound responsible for the observed migratory activity as taurocholic acid. Importantly, the study confirms that taurocholic acid enhances cell migration in JEG-3 cells. CONCLUSION: The results of this study emphasize the potential of Antarctic fish extracts in promoting extravillous trophoblast migration and invasion, which are critical for successful pregnancy.
Subject(s)
Cell Movement , Matrix Metalloproteinase 9 , Perciformes , Proto-Oncogene Proteins c-akt , Trophoblasts , beta Catenin , Animals , Humans , Antarctic Regions , beta Catenin/metabolism , Cell Line, Tumor , Cell Movement/drug effects , Matrix Metalloproteinase 9/metabolism , Matrix Metalloproteinase 9/genetics , Perciformes/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/drug effects , Trophoblasts/drug effects , Trophoblasts/metabolismABSTRACT
Skeletal muscle aging results in the gradual suppression of myogenesis, leading to muscle mass loss. However, the specific role of cardiolipin in myogenesis has not been determined. This study investigated the crucial role of mitochondrial cardiolipin and cardiolipin synthase 1 (Crls1) in age-related muscle deterioration and myogenesis. Our findings demonstrated that cardiolipin and Crls1 are downregulated in aged skeletal muscle. Moreover, the knockdown of Crls1 in myoblasts reduced mitochondrial mass, activity, and OXPHOS complex IV expression and disrupted the structure of the mitochondrial cristae. AAV9-shCrls1-mediated downregulation of Crls1 impaired muscle regeneration in a mouse model of cardiotoxin (CTX)-induced muscle damage, whereas AAV9-mCrls1-mediated Crls1 overexpression improved regeneration. Overall, our results highlight that the age-dependent decrease in CRLS1 expression contributes to muscle loss by diminishing mitochondrial quality in skeletal muscle myoblasts. Hence, modulating CRLS1 expression is a promising therapeutic strategy for mitigating muscle deterioration associated with aging, suggesting potential avenues for developing interventions to improve overall muscle health and quality of life in elderly individuals.
Subject(s)
Muscle, Skeletal , Muscular Diseases , Regeneration , Animals , Muscle, Skeletal/metabolism , Muscle, Skeletal/pathology , Mice , Muscular Diseases/metabolism , Muscular Diseases/etiology , Muscular Diseases/pathology , Muscular Diseases/genetics , Aging/metabolism , Muscle Development , Mitochondria/metabolism , Disease Models, Animal , Humans , Cardiolipins/metabolism , Mitochondrial Proteins/metabolism , Mitochondrial Proteins/genetics , Male , Myoblasts/metabolismABSTRACT
The implications of administration of mRNA vaccines to individuals with chronic inflammatory diseases, including myocarditis, rheumatoid arthritis (RA), and inflammatory bowel disease (IBD), are unclear. We investigated mRNA vaccine effects in a chronic inflammation mouse model implanted with an LPS pump, focusing on toxicity and immunogenicity. Under chronic inflammation, mRNA vaccines exacerbated cardiac damage and myocarditis, inducing mild heart inflammation with heightened pro-inflammatory cytokine production and inflammatory cell infiltration in the heart. Concurrently, significant muscle damage occurred, with disturbances in mitochondrial fusion and fission factors signaling impaired muscle repair. However, chronic inflammation did not adversely affect muscles at the vaccination site or humoral immune responses; nevertheless, it partially reduced the cell-mediated immune response, particularly T-cell activation. These findings underscore the importance of addressing mRNA vaccine toxicity and immunogenicity in the context of chronic inflammation, ensuring their safe and effective utilization, particularly among vulnerable populations with immune-mediated inflammatory diseases.
ABSTRACT
Premature ovarian insufficiency (POI) is a typical disorder of amenorrhea that lasts for a minimum of four months in women < 40 years old and is typically characterized by reduced estrogen levels and elevated serum concentrations of follicle-stimulating hormone. We collected urine samples from two participant cohorts from Gil Hospital of Gachon University (Incheon, Korea): a sequencing cohort of 19 participants (seven patients with POI (POI patients without Turner syndrome), seven patients with Turner syndrome (POI patients with Turner syndrome), and five control individuals (age-matched controls with confirmed ovarian sufficiency)) and a validation cohort of 46 participants (15 patients with POI, 11 patients with Turner syndrome, and 20 control individuals). Among differentially expressed miRNAs, hsa-miR-4516 was significantly upregulated in patients with POI in both cohorts, independent of the presence of Turner syndrome. Moreover, the upregulation of miR-4516 was confirmed in the ovary-but not in the uterus-of a cyclophosphamide and busulfan-induced POI mouse model. This was accompanied by a decrease in STAT3 protein level, a predicted target of miR-4516, via miRTarBase2020. Our study provides compelling evidence that miR-4516 is highly expressed in patients with POI and POI mouse models, suggesting that miR-4516 is a diagnostic marker of POI.
Subject(s)
Exosomes , MicroRNAs , Primary Ovarian Insufficiency , Turner Syndrome , Animals , Biomarkers , Busulfan , Cyclophosphamide , Estrogens , Female , Follicle Stimulating Hormone , Humans , Mice , MicroRNAs/genetics , Primary Ovarian Insufficiency/genetics , STAT3 Transcription Factor , Turner Syndrome/geneticsABSTRACT
The motility of endometrial stromal cells (ESCs) contributes to the restoration of the endometrial functional layer and subsequently supports the trophoblast invasion during early pregnancy. Following ESCs differentiation through decidualization in response to progesterone during the menstrual cycle and embryo implantation, decidualized ESCs (D-ESCs) have greater motility and invasive activity. The human proinsulin-connecting peptide (C-peptide) is produced in equimolar amounts during the proteolysis of insulin in pancreatic ß-cells. However, the function of C-peptide in the cellular motility of the human endometrium remains unexamined. In the present study, C-peptide was identified as a determinant of undecidualized human endometrial stromal cells (UnD-ESCs) migration. C-peptide promoted the migration and invasion of UnD-ESCs and trophoblast-derived Jeg3 cells, but not that of ESCs post decidualization, a functional and biochemical differentiation of UnD-ESCs. Both Akt and protein phosphatase 1 regulated ß-catenin phosphorylation in UnD-ESCs, not D-ESCs, thereby promoting ß-catenin nuclear translocation in C-peptide-treated UnD-ESCs. C-peptide was also observed to increase matrix metallopeptidase-9 (MMP9) activity by increasing MMP9 expression and decreasing the expression of metallopeptidase inhibitor 1 (TIMP1) and TIMP3. Their expression was modulated by the direct binding of ß-catenin in the regulatory region of the promoter of MMP9, TIMP1, and TIMP3. Inhibition of either ß-catenin or MMP9 dampened C-peptide-enhanced migration in UnD-ESCs. Together, these findings suggest that C-peptide levels are critical for the regulation of UnD-ESC migration, providing evidence for the association between C-peptide levels and the failure rate of trophoblast invasion by inducing abnormal migration in UnD-ESCs in hyperinsulinemia or PCOS patients.
ABSTRACT
BACKGROUND: Muscle regeneration includes proliferation and differentiation of muscle satellite cells, which involves the mammalian target of rapamycin (mTOR). We identified the C-terminal unique attached sequence motif (UNE) domain of leucyl-tRNA synthetase (LRS-UNE-L) as an mTORC1 (mTOR complex1)-activating domain that acts through Vps34 and phospholipase D1 (PLD1) when introduced in the form of a muscle-enhancing peptide. METHODS: In vitro Vps34 lipid kinase assay, phosphatidylinositol 3-phosphate (PI(3)P) measurement, in vivo PLD1 assay, and western blot assay were performed in HEK293 cells to test the effect of the LRS-UNE-L on the Vps34-PLD1-mTOR pathway. Adeno-associated virus (AAV)-LRS-UNE-L was transduced in C2C12 cells in vitro, in BaCl2 -injured tibialis anterior (TA) muscles, and in 18-month-old TA muscles to analyse its effect on myogenesis, muscle regeneration, and aged muscle, respectively. The muscle-specific cell-permeable peptide M12 was fused with LRS-UNE-L and tested for cell integration in C2C12 and HEK293 cells using FACS analysis and immunocytochemistry. Finally, M12-LRS-UNE-L was introduced into BaCl2 -injured TA muscles of 15-week-old Pld1+/+ or Pld1-/- mice, and its effect was analysed by measurement of cross-sectional area of regenerating muscle fibres. RESULTS: The LRS-UNE-L expression restored amino acid-induced S6K1 phosphorylation in LRS knockdown cells in a RagD GTPases-independent manner (421%, P = 0.007 vs. LRS knockdown control cells). The LRS-UNE-L domain was directly bound to Vps34; this interaction was accompanied by increases in Vps34 activity (166%, P = 0.0352), PI(3)P levels (146%, P = 0.0039), and PLD1 activity (228%, P = 0.0294) compared with amino acid-treated control cells, but it did not affect autophagic flux. AAV-delivered LRS-UNE-L domain augmented S6K1 phosphorylation (174%, P = 0.0013), mRNA levels of myosin heavy chain (MHC) (122%, P = 0.0282) and insulin-like growth factor 2 (IGF2) (146%, P = 0.008), and myogenic fusion (133%, P = 0.0479) in C2C12 myotubes. AAV-LRS-UNE-L increased the size of regenerating muscle fibres in BaCl2 -injured TA muscles (124%, P = 0.0279) (n = 9-10), but it did not change the muscle fibre size of TA muscles in old mice. M12-LRS-UNE-L was preferentially delivered into C2C12 cells compared with HEK293 cells and augmented regeneration of BaCl2 -injured TA muscles in a PLD1-dependent manner (116%, P = 0.0022) (n = 6). CONCLUSIONS: Our results provide compelling evidence that M12-LRS-UNE-L could be a muscle-enhancing protein targeting mTOR.
Subject(s)
Muscle, Skeletal , Signal Transduction , Aged , Animals , HEK293 Cells , Humans , Mammals , Mice , Muscle, Skeletal/physiology , Phosphatidylinositol Phosphates , RegenerationABSTRACT
Premature ovarian insufficiency (POI) is the loss of normal ovarian function before the age of 40 years, a condition that affects approximately 1% of women under 40 years old and 0.1% of women under 30 years old. It is biochemically characterized by amenorrhea with hypoestrogenic and hypergonadotropic conditions, in some cases, causing loss of fertility. Heterogeneity of POI is registered by genetic and non-genetic causes, such as autoimmunity, environmental toxins, and chemicals. The identification of possible causative genes and selection of candidate genes for POI confirmation remain to be elucidated in cases of idiopathic POI. This review discusses the current understanding and future prospects of heterogeneous POI. We focus on the genetic basis of POI and the recent studies on non-coding RNA in POI pathogenesis as well as on animal models of POI pathogenesis, which help unravel POI mechanisms and potential targets. Despite the latest discoveries, the crosstalk among gene regulatory networks and the possible therapies targeting the same needs to explore in near future.
ABSTRACT
BACKGROUND & AIMS: Sarcopenic obesity (SO) increases the risk of mortality more than sarcopenia or obesity alone. Sarcopenia weakens the peripheral and respiratory muscles, leading to respiratory complications. It also induces mitochondrial dysfunction in the peripheral muscle; however, whether mitochondrial dysfunction in respiratory muscles differs among individuals with obesity, sarcopenia, and SO remains unknown. We evaluated the deterioration of respiratory muscle strength and mitochondrial function among normal, sarcopenia, obesity, and SO subjects. METHODS: Twenty-five patients who underwent lung resections were enrolled between April 2017 and January 2021, and their intercostal muscles were harvested. Based on their L3 muscle index and visceral fat area, the patients were divided into four groups (normal, obesity, sarcopenia, and SO). The clinical data, mRNA expression, and protein expressions associated with mitochondrial biogenesis/fusion/fission in the intercostal muscles were compared among the four groups. RESULTS: The respiratory muscle strength was evaluated using peak expiratory flow rate (PEFR). The PEFR values of the four groups were not significantly different. The levels of pAkt/Akt and mTOR (a marker of protein synthesis) were not significantly different among the four groups; however, those in the SO group were substantially lower than those in the sarcopenia or obesity groups. The levels of Atrogen-1 and MuRF1 (a marker of protein degradation) were not significantly different among the four groups; however, those in the SO group were substantially higher than those in the sarcopenia or obesity groups. Expression of PGC1-α (a marker of mitochondrial biogenesis) in the SO group was significantly lower than that in the normal group. MFN1 and MFN2 (marker of mitochondrial fusion) levels were significantly lower in the SO group than those in the normal group. DRP1 (a marker of mitochondrial fission) level in the SO group was substantially lower than that in the normal group. The expression of TNF-α (a pro-inflammatory cytokine) in the SO group was substantially lower than that in the normal group. CONCLUSION: Our results suggest that the deterioration of protein synthesis and degradation of mitochondrial function in the respiratory muscles was most prominent in the SO before the weakening of the respiratory muscles. The deterioration mechanism may differentially regulate obesity, sarcopenia, and SO.
Subject(s)
Mitochondria, Muscle/pathology , Obesity/pathology , Sarcopenia/pathology , Adult , Aged , Aged, 80 and over , Cytokines/genetics , Cytokines/metabolism , Female , Gene Expression Regulation , Humans , Inflammation/metabolism , Inflammation/pathology , Male , Middle Aged , Muscle, Skeletal/metabolism , Obesity/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Sarcopenia/metabolismABSTRACT
Guanine nucleotide exchange factors (GEFs) activate GTPases by stimulating the release of guanosine diphosphate to permit the binding of guanosine triphosphate. ARHGEF3 or XPLN (exchange factor found in platelets, leukemic, and neuronal tissues) is a selective guanine nucleotide exchange factor for Rho GTPases (RhoGEFs) that activates RhoA and RhoB but not RhoC, RhoG, Rac1, or Cdc42. ARHGEF3 contains the diffuse B-cell lymphoma homology and pleckstrin homology domains but lacks similarity with other known functional domains. ARHGEF3 also binds the mammalian target of rapamycin complex 2 (mTORC2) and subsequently inhibits mTORC2 and Akt. In vivo investigation has also indicated the communication between ARHGEF3 and autophagy-related muscle pathologies. Moreover, studies on genetic variation in ARHGEF3 and genome-wide association studies have predicted exciting novel roles of ARHGEF3 in controlling bone mineral density, platelet formation and differentiation, and Hirschsprung disease. In conclusion, we hypothesized that additional biochemical and functional studies are required to elucidate the detailed mechanism of ARHGEF3-related pathologies and therapeutics.
ABSTRACT
Decidualization refers to the functional differentiation of endometrial stromal cells and plays a significant role in embryo implantation and pregnancy. C-peptide is excreted in equimolar concentrations as that of insulin during the metabolism of proinsulin in pancreatic beta-cells. High levels of C-peptide are correlated with hyperinsulinemia and polycystic ovarian syndrome, which show a defect in decidualization. However, the role of C-peptide in decidualization has not yet been studied. Here, we identified C-peptide as an endogenous antideciduogenic factor. This inhibitory function was confirmed by the reduced expression of decidual markers, including prolactin, insulin-like growth factor-binding protein-1, and Forkhead box protein O1 as well as by the fibroblastic morphological change in the presence of C-peptide. C-peptide also enhanced cellular senescence and decreased the proportion of apoptotic cells during decidualization. In addition, C-peptide potentiated the inhibitory effects of both insulin and palmitic acid in an AKT- and autophagy-independent manner, respectively. Furthermore, C-peptide augmented protein phosphatase 1 (PP1) activity, leading to a reduction in the inhibitory phosphorylation of glycogen synthase kinase (GSK)3ß, which resulted in enhanced cellular senescence and decreased apoptosis during decidualization. Taken together, our findings suggest that C-peptide is an antideciduogenic factor acting via the regulation between PP1 and GSK3ß in patients with hyperinsulinemia.
ABSTRACT
Flounders have been widely used as indicator species for monitoring the benthic environment of marine coastal regions owing to their habitat and feeding preferences in or on sandy sediments. Here, a single-step, sensitive, specific, and simple luciferase assay was developed, using the olive flounder cyp1a1 gene, for effective detection of CYP1A-inducing contaminants in coastal sediments. The developed cyp1a1-luciferase assay was highly sensitive to the widely used CYP1A inducers 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), benzo[a]pyrene (B[a]P), and 3,3',4,4',5-pentachlorobiphenyl (PCB 126). In the case of TCDD, significant dose-dependent increases in luciferase activity (0.3-300 ng/L) were detected. The assay was more sensitive to PCB 126 than to B[a]P. The assay also involved the highly sensitive expression of luciferase to extracted mixtures of PCBs and polycyclic aromatic hydrocarbons (PAHs) collected from coastal sediments. PCBs were more capable of cyp1a1 induction in the assay system at small doses than PAHs in environmental samples. Using the cyp1a1-luciferase assay along with water or sediment chemistry will certainly aid in diagnosing CYP1A-inducing contaminants in coastal environments.
Subject(s)
Flounder , Polychlorinated Biphenyls , Polychlorinated Dibenzodioxins , Polycyclic Aromatic Hydrocarbons , Animals , Cytochrome P-450 CYP1A1/genetics , Luciferases/geneticsABSTRACT
Mammalian target of rapamycin (mTOR) is a master regulator of cell growth and metabolism, which is activated in response to intra- and extracellular signals, including nutrients, growth factors, and cellular energy levels. The frequent dysregulation of mTOR signaling in cancer makes it an attractive therapeutic target, and several types of mTOR inhibitors have been developed. Nanoparticle-based mTOR modulators are predicted to target various cancers and deliver as well as release drugs in a controlled manner, resulting in enhanced bioavailability and reduced side effects. This mini-review is focused on the molecular mechanism of nanoparticle-based mTOR modulator action as well as the current development of mTOR inhibitors using nanoparticles. Understanding the biological function of nanoparticle-based mTOR modulators will contribute to the development of efficient nano-therapeutics for the treatment of cancers.
Subject(s)
Molecular Targeted Therapy , Nanotechnology , Neoplasms/drug therapy , Neoplasms/metabolism , Signal Transduction , TOR Serine-Threonine Kinases/metabolism , Autophagy , Humans , Neoplasms/pathologyABSTRACT
TNF-related apoptosis-inducing ligand (TRAIL) is known to induce apoptosis in cancer cells, although non-apoptotic functions have also been reported for this cytokine in various cell types. TRAIL and its receptor TRAIL-R2 are expressed in skeletal muscles, but a potential role of muscle-derived TRAIL in myogenesis has not been explored. Here we report that TRAIL is an autocrine regulator of myogenic differentiation. Knockdown of TRAIL or TRAIL-R2 enhanced C2C12 myoblast differentiation, and recombinant TRAIL inhibited expression of the cell cycle inhibitor p21, accompanied by suppression of myoblasts from exiting the cell cycle, a requisite step in the myogenic differentiation process. Blocking cell cycle progression restored differentiation from inhibition by recombinant TRAIL, supporting the notion that TRAIL exerts its effect in myogenesis through modulating cell cycle exit. We also found that TRAIL knockdown led to enhanced muscle regeneration in mice upon injury, recapitulating the in vitro observation. Additionally, inhibition of ERK activation reversed the negative effect of recombinant TRAIL on p21 expression and myoblast differentiation, suggesting that ERK signaling may be a mediator of TRAIL's function to suppress cell cycle withdrawal and inhibit differentiation. Taken together, our findings uncover a muscle cell-autonomous non-apoptotic function of TRAIL in skeletal myogenesis.
Subject(s)
Apoptosis/physiology , Cell Differentiation/physiology , Muscle Development/physiology , TNF-Related Apoptosis-Inducing Ligand/metabolism , Animals , Cell Cycle/physiology , Humans , Mice , Muscle, Skeletal/metabolism , Myoblasts/cytology , Signal Transduction/physiologyABSTRACT
Sarcopenia is the degenerative loss of skeletal muscle mass and function associated with aging and occurs in the absence of any underlying disease or condition. A comparison of the age-related molecular signaling signatures of different muscles has not previously been reported. In this study, we compared the age-related molecular signaling signatures of the intercostal muscles, the diaphragm, and the gastrocnemii using 6-month and 20-month-old rats. The phosphorylation of Akt, ribosomal S6, and Forkhead box protein O1 (FoxO1) in diaphragms significantly increased with age, but remained unchanged in the intercostal and gastrocnemius muscles. In addition, ubiquitin-proteasome degradation, characterized by the levels of MuRF1 and Atrogin-1, did not change with age in all rat muscles. Interestingly, an increase in LC3BII and p62 levels marked substantial blockage of autophagy in aged gastrocnemii but not in aged respiratory muscles. These changes in LC3BII and p62 levels were also associated with a decrease in markers of mitochondrial quality control. Therefore, our results suggest that the age-related signaling events in respiratory muscles differ from those in the gastrocnemii, most likely to preserve the vital functions played by the respiratory muscles.
Subject(s)
Aging/metabolism , Muscle, Skeletal/metabolism , Muscular Atrophy/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , TOR Serine-Threonine Kinases/metabolism , Animals , Autophagy/genetics , Biomarkers , Disease Models, Animal , Gene Expression , Intercostal Muscles/metabolism , Mitochondria, Muscle/genetics , Mitochondria, Muscle/metabolism , Muscular Atrophy/genetics , Muscular Atrophy/pathology , Rats , Respiratory Muscles/metabolism , Ubiquitin/genetics , Ubiquitin/metabolismABSTRACT
[This corrects the article DOI: 10.3389/fcell.2019.00329.].
ABSTRACT
Type 2 diabetes (T2D) patients suffer from dyspnea, which contributes to disease-related morbidity. Although T2D has been reported to induce a catabolic state in skeletal muscle, whether T2D induces muscle wasting in respiratory muscles has not yet been investigated. In this study, we examine the difference in the molecular signaling signature of muscle wasting between the intercostal and gastrocnemius muscles using db/db mice, a well-known diabetic mouse model. Akt phosphorylation was significantly decreased in both the intercostal and gastrocnemius muscles of db/db mice and was accompanied by a decrease in mTORC1 activity. In addition, FoxO phosphorylation was suppressed, and ubiquitin-proteasome degradation, characterized by the level of Atrogin-1 and MuRF1, was subsequently enhanced in both muscle types of db/db mice. An increase in LC3BII levels and a decrease in p62 levels marked the occurrence of substantial autophagy in the gastrocnemius muscle but not in the intercostal muscles of db/db mice. Therefore, we suggest that the signaling events of muscle wasting in the intercostal muscles of db/db mice are different from those in the gastrocnemius muscle of db/db mice.
Subject(s)
Diabetes Complications/metabolism , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Type 2/metabolism , Muscle Proteins/metabolism , Muscle, Skeletal/metabolism , Muscular Atrophy/metabolism , Signal Transduction , Animals , Diabetes Complications/genetics , Diabetes Complications/pathology , Diabetes Mellitus, Experimental/genetics , Diabetes Mellitus, Experimental/pathology , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/pathology , Male , Mechanistic Target of Rapamycin Complex 1/genetics , Mechanistic Target of Rapamycin Complex 1/metabolism , Mice , Mice, Transgenic , Muscle Proteins/genetics , Muscle, Skeletal/pathology , Muscular Atrophy/genetics , Muscular Atrophy/pathologyABSTRACT
The skeletal muscle system has evolved to maintain body posture against a constant gravitational load. Mammalian target of rapamycin (mTOR) regulates the mechanically induced increase in the skeletal muscle mass. In the present study, we investigated mTOR pathway in C2C12 myoblasts in a model of mechanical unloading by creating a simulated microgravity (SM) using 3 D clinorotation. SM decreased the phosphorylation of Akt at Ser 473, which was mediated by mTOR complex 2 (mTORC2), in C2C12 myoblasts, leading to a decrease in the cell growth rate. Subsequently, SM inhibited C2C12 myogenesis in an Akt-dependent manner. In addition, SM increased the phospholipase D (PLD) activity by enhancing PLD2 expression, resulting in the dissociation of mSIN1 from the mTORC2, followed by decrease in the phosphorylation of Akt at Ser 473, and FOXO1 at Ser 256 in C2C12 myoblasts. Exposure to SM decreased the autophagic flux of C2C12 myoblasts by regulation of mRNA level of autophagic genes in a PLD2 and FOXO1-dependent manner, subsequently, resulting in a decrease in the C2C12 myogenesis. In conclusion, by analyzing the molecular signature of C2C12 myogenesis using SM, we suggest that the regulatory axis of the PLD2 induced Akt/FOXO1, is critical for C2C12 myogenesis.
Subject(s)
Muscle Development/physiology , Myoblasts/physiology , Phospholipase D/metabolism , Weightlessness Simulation/adverse effects , Animals , Cell Culture Techniques/methods , Cell Differentiation/physiology , Cell Line , Forkhead Box Protein O1/metabolism , Mechanistic Target of Rapamycin Complex 2/metabolism , Mice , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/physiology , Weightlessness Simulation/methodsABSTRACT
Decidualization is characterized by the differentiation of endometrial stromal cells (eSCs), which is critical for embryo implantation and maintenance of pregnancy. In the present study, we investigated the possible effect of simulated microgravity (SM) on the process of proliferation and in vitro decidualization using primary human eSCs. Exposure to SM for 36 h decreased the proliferation and migration of eSCs significantly, without inducing cell death and changes in cell cycle progression. The phosphorylation of Akt decreased under SM conditions in human eSCs, accompanied by a simultaneous decrease in the level of matrix metalloproteinase (MMP)-2 and FOXO3a. Treatment with Akti, an Akt inhibitor, decreased MMP-2 expression, but not FOXO3a expression. The decreased level of FOXO3a under SM conditions impeded autophagic flux by reducing the levels of autophagy-related genes. In addition, pre-exposure of eSCs to SM significantly inhibited 8-Br-cAMP induced decidualization, whereas restoration of the growth status under SM conditions by removing 8-Br-cAMP remained unchanged. Treatment of human eSCs with SC-79, an Akt activator, restored the reduced migration of eSCs and decidualization under SM conditions. In conclusion, exposure to SM inhibited decidualization in eSCs by decreasing proliferation and migration through Akt/MMP and FOXO3a/autophagic flux.