American journal of physiology. Cell physiology最新文献

{"title":"<i>O-</i>GlcNAcylation regulates tyrosine hydroxylase serine 40 phosphorylation and l-DOPA levels.","authors":"Bruno da Costa Rodrigues, Miguel Clodomiro Dos Santos Lucena, Anna Carolina Rego Costa, Isadora de Araújo Oliveira, Mariana Thaumaturgo, Yolanda Paes-Colli, Danielle Beckman, Sergio T Ferreira, Fernando Garcia de Mello, Ricardo Augusto de Melo Reis, Adriane Regina Todeschini, Wagner Barbosa Dias","doi":"10.1152/ajpcell.00215.2024","DOIUrl":"10.1152/ajpcell.00215.2024","url":null,"abstract":"<p><p>β-<i>O-</i>linked-<i>N</i>-acetylglucosamine (<i>O-</i>GlcNAcylation) is a post-translational modification (PTM) characterized by the covalent attachment of a single moiety of <i>N</i>-acetylglucosamine (GlcNAc) on serine/threonine residues in proteins. Tyrosine hydroxylase (TH), the rate-limiting step enzyme in the catecholamine synthesis pathway and responsible for the production of the dopamine precursor, l-3,4-dihydroxyphenylalanine (l-DOPA), has its activity regulated by phosphorylation. Here, we show an inverse feedback mechanism between <i>O-</i>GlcNAcylation and phosphorylation of TH at serine 40 (TH pSer40). First, we showed that, during PC12 cells neuritogenesis, TH <i>O-</i>GlcNAcylation decreases concurrently with the increase of pSer40. In addition, an increase in <i>O-</i>GlcNAcylation induces a decrease in TH pSer40 only in undifferentiated PC12 cells, whereas the decrease in <i>O-</i>GlcNAcylation leads to an increase in TH pSer40 levels in both undifferentiated and differentiated PC12 cells. We further show that this feedback culminates on the regulation of l-DOPA intracellular levels. Interestingly, it is noteworthy that decreasing <i>O-</i>GlcNAcylation is much more effective on TH pSer40 regulation than increasing its levels. Finally, ex vivo analysis confirmed the upregulation of TH pSer40 when <i>O-</i>GlcNAcylation levels are reduced in dopaminergic neurons from C57Bl/6 mice. Taken together, these findings demonstrate a dynamic control of l-DOPA production by a molecular cross talk between <i>O-</i>GlcNAcylation and phosphorylation at Ser40 in TH.<b>NEW & NOTEWORTHY</b> This study shows how β-<i>O-</i>linked-<i>N</i>-acetylglucosamine (<i>O-</i>GlcNAcylation) modulates tyrosine hydroxylase (TH) activity, revealing a negative feedback loop with Ser40 phosphorylation both in vitro and ex vivo, which directly influences on l-3,4-dihydroxyphenylalanine (l-DOPA) production. These findings offer insights into neurotransmitter homeostasis regulation, with implications for understanding and potentially treating disorders linked to aberrant catecholamine signaling.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C825-C835"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143051240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sex-specific activation of platelet purinergic signaling is key in local cytokine release and phagocytosis in the peritoneal cavity in intra-abdominal sepsis.","authors":"Philomena Entsie, Emmanuel Boadi Amoafo, Ying Kang, Thomas Gustad, Glenn P Dorsam, Mark R Frey, Elisabetta Liverani","doi":"10.1152/ajpcell.00116.2024","DOIUrl":"10.1152/ajpcell.00116.2024","url":null,"abstract":"<p><p>Intra-abdominal sepsis is a life-threatening complex syndrome caused by microbes in the gut microbiota invading the peritoneal cavity. It is one of the major complications of intra-abdominal surgery. To date, only supportive therapies are available. No studies have investigated the progression of intra-abdominal sepsis in the peritoneal cavity. Our group has shown that platelets play an essential role during sepsis, and blocking purinergic signaling in platelets through P2Y₁ and P2Y₁₂ antagonism significantly lowered inflammatory levels and improved survival in a murine model of sepsis. Here, we tested whether antagonizing purinergic signaling in platelets in the peritoneal cavity can reduce the local release of cytokines and modulate platelet interaction with the immune system. We used cecal ligation and puncture (CLP) to induce sepsis followed by intraperitoneal administration of MRS2279 (P2Y₁ antagonist) or ticagrelor (P2Y₁₂ antagonist) in male and female mice. The peritoneal cavity fluid (PCF) was collected 4 or 24 h post-CLP and analyzed for cell recruitment, platelet markers, cytokines, and platelet immune cell interactions. Platelet markers were increased 24 h after CLP, although the total platelet count in the peritoneal cavity was lower than the blood. Blocking P2Y₁₂ or P2Y₁ improved bacterial clearance in the PCF in a sex-dependent manner. The influx of immune cells in the peritoneal cavity was altered by blocking P2Y₁₂ or P2Y₁ sex-dependently. Blocking P2Y₁ and P2Y₁₂ receptors can enhance the phagocytic activity in the peritoneal cavity in a sex- and time-related manner, and platelets significantly contribute to the development and progression of sepsis in the peritoneal cavity.<b>NEW & NOTEWORTHY</b> Intra-abdominal sepsis is a challenging complication postabdominal surgery caused by perforations of the gastrointestinal tract where microbes invade the peritoneal cavity. This leads to local cytokine release and immune cell dysfunction. Our data identify platelets as key players in mediating inflammation in intra-abdominal sepsis. We have shown that blocking purinergic signaling in the peritoneal cavity reduced cytokine release and cell-cell interactions differently in males and females, hence a sex-specific strategy to improve intra-abdominal sepsis.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C791-C805"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Activated cardiac fibroblasts are a primary source of high-molecular-weight hyaluronan production.","authors":"Danielle T Little, Caitlin M Howard, Emma Pendergraft, Kenneth R Brittian, Timothy N Audam, Exile W Lukudu, Juliette Smith, Daniel Nguyen, Yoshihiro Nishida, Yu Yamaguchi, Robert E Brainard, Richa A Singhal, Steven P Jones","doi":"10.1152/ajpcell.00786.2024","DOIUrl":"10.1152/ajpcell.00786.2024","url":null,"abstract":"<p><p>During acute myocardial infarction, the composition of the extracellular matrix changes remarkably. One of the most notable changes in the extracellular matrix is in the accumulation of collagen; however, hyaluronan rivals collagen in its abundance. Yet, the extent to which specific cells and enzymes may contribute to such accumulation has been largely unexplored. Here, we hypothesized that activated cardiac fibroblasts produce hyaluronan via hyaluronan synthase 2 (HAS2). We show that hyaluronan accumulates following myocardial infarction and persists through at least 4 wk. Our analyses of failing heart RNA sequencing data suggest that fibroblasts are the cells most changed in the expression of <i>HAS2</i>. Given these insights, we used HAS2 gain- and loss-of-function approaches to examine the extent to which activated cardiac fibroblasts produce hyaluronan. Transforming growth factor β (TGFβ)-induced activation of fibroblasts caused a significant increase in <i>Has2</i> mRNA and concomitant accumulation of hyaluronan >1 MDa in size. Deletion of <i>Has2</i> abrogated TGFβ-induced production of hyaluronan. In addition, overexpression of <i>Has2</i> was sufficient to cause an increase in hyaluronan accumulation in the absence of TGFβ-induced activation. Our data indicated negligible impacts of <i>Has2</i> on proliferation, migration, and collagen production. Exposing fibroblasts to exogenous hyaluronan also had minimal impact on fibroblasts. We also assessed whether fibroblast-borne <i>Hyal2</i> plays a role in the degradation of hyaluronan, and our data indicated little impact of <i>Hyal2</i> on hyaluronan accumulation (or even any impacts on the transcriptional profile of fibroblasts). Activated fibroblasts produce high-molecular-weight hyaluronan via <i>Has2</i>, which occurs independent of other fibroblast functions.<b>NEW & NOTEWORTHY</b> Activated cardiac fibroblasts produce copious quantities of collagen, and much is known about this process. They also produce hyaluronan, which is abundant in the extracellular matrix, but less is known about hyaluronan. Here, we identify cardiac fibroblasts as major producers of hyaluronan and, specifically, that they produce high-molecular-weight hyaluronan via HAS2. This has important implications for ventricular remodeling and for metabolic regulation of activated fibroblasts, as they produce this abundant matrix component.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C939-C953"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143051019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An endogenous aryl hydrocarbon receptor ligand dysregulates endothelial functions, transcriptome, and phosphoproteome.","authors":"Ying-Jie Zhao, Si-Yan Zhang, Ying-Ying Wei, Hui-Hui Li, Wei Lei, Kai Wang, Sathish Kumar, Chi Zhou, Jing Zheng","doi":"10.1152/ajpcell.00849.2024","DOIUrl":"10.1152/ajpcell.00849.2024","url":null,"abstract":"<p><p>We have reported that an endogenous aryl hydrocarbon receptor (AhR) ligand, 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), inhibits functions of human umbilical vein endothelial cells (HUVECs) and induces preeclampsia (PE)-like symptoms in rats. Herein, we tested the hypothesis that ITE impairs endothelial functions via disturbing transcriptome and phosphoproteome in HUVECs. We measured AhR activity in human maternal and umbilical vein sera from PE and normotensive (NT) pregnancies. The serum-induced changes in CYP1A1/B1 mRNA (indexes of AhR activation) in HUVECs were quantified using quantitative reverse transcription polymerase chain reaction (RT-qPCR). ITE's effects on endothelial proliferation and monolayer integrity in female and male HUVECs were determined. We profiled ITE-induced changes in transcriptome and phosphoproteome in HUVECs using RNA-seq and bottom-up phosphoproteomics, respectively. After 12 h of treatment, umbilical vein sera from PE increased CYP1A1 mRNA (1.7-fold of NT) in HUVECs, which was blocked by CH223191, an AhR antagonist. ITE dose-dependently inhibited endothelial proliferation (76%-87% of control) and time-dependently reduced endothelial integrity with a maximum inhibition (∼10%) at 40 h. ITE induced 140 and 80 differentially expressed genes in female and male HUVECs, respectively. ITE altered phosphorylation of 92 and 105 proteins at 4 and 24 h, respectively, in HUVECs. These ITE-dysregulated genes and phosphoproteins were enriched in biological functions and pathways that are relevant to heart, liver, and kidney diseases, vascular functions, and inflammatory responses. Thus, endogenous AhR ligands may impair endothelial functions by disturbing transcriptome and phosphoproteome. These AhR ligand-dysregulated genes and phosphoproteins may be therapeutic and cell sex-specific targets for PE-induced endothelial dysfunction.<b>NEW & NOTEWORTHY</b> Preeclampsia elevates AhR agonistic activities in fetal circulation and alters immune cell gene signatures of human umbilical vein endothelial cells (HUVECs). An endogenous AhR ligand (ITE) decreases cell proliferation and monolayer integrity in HUVECs in vitro. ITE dysregulates transcriptome in HUVECs in a fetal sex-specific manner. ITE also disrupts phosphoproteome in HUVECs. These ITE-dysregulated genes and phosphoproteins are highly relevant to diseases of the heart, vascular function, and inflammatory responses.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C954-C966"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143187659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inhibition of Bif-1 confers cardio-protection in myocardial infarction.","authors":"Yi Xu, Zhirui Zheng, Xin Jiang, Xinqiuyue Wang, Qiuxia Xu, Xianneng Lu, Yipu Huang, Yuan Qin, Ning Hou, Yun Liu","doi":"10.1152/ajpcell.00473.2024","DOIUrl":"10.1152/ajpcell.00473.2024","url":null,"abstract":"<p><p>Myocardial infarction (MI) remains a major cause of chronic heart failure. Endoplasmic reticulum (ER) stress is an emerging therapeutic strategy to prevent adverse remodeling of the infarcted heart. However, little is known about how Bax-interacting protein 1 (Bif-1), a member of the endophilin B family, is involved in mediating cardiac ER stress in ischemic heart disease. Here, a combination of a left anterior descending coronary artery ligation mouse model and an adenovirus-based transfection strategy was used to investigate the effect of Bif-1 on cardiac remodeling and function after MI. 4-Phenylbutyric acid (4-PBA) was used to understand the role of ER stress in cardiac remodeling. To discover the molecular mechanism, an RNA sequencing study was performed. We found that Bif-1 expression was highly elevated in the heart infarct border zone post-MI and neonatal rat cardiomyocytes treated with oxygen and glucose deprivation. Adenovirus-based knockdown of Bif-1 protected the heart from MI as demonstrated by attenuated maladaptive remodeling and preserved contractile function. ER stress inhibition by 4-PBA alleviated the adverse effects of Bif-1 overexpression on cardiac structure and function. Furthermore, we explored the underlying mechanism by RNA sequencing and identified Bif-1 as a molecule involved in cardiac lipid metabolism. In conclusion, our study identifies Bif-1 as a negative regulator of cardiac protection in MI. Inhibition of Bif-1 alleviates ER stress, which may restore lipid metabolism homeostasis to preserve cardiac function post-MI. Therefore, Bif-1 is a potential novel therapeutic target for ischemic heart disease.<b>NEW & NOTEWORTHY</b> Our study demonstrated that Bif-1 contributes to adverse cardiac remodeling and dysfunction following MI by promoting ER stress. Pharmacological inhibition of ER stress ameliorates cardiac remodeling and dysfunction. In addition, we identified Bif-1 as a negative regulator of cardiac lipid metabolism post-MI, as shown by elevated expression of Acox1, Pla2g7, Acsbg1, Acsl5, Ch25h, and Bcat1 in the heart. These findings suggest that Bif-1 plays a crucial role in cardiac decline post-MI.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C1076-C1089"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143466703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dysregulation of synaptic transcripts underlies network abnormalities in ALS patient-derived motor neurons.","authors":"Anna M Kollstrøm, Nicholas Christiansen, Axel Sandvig, Ioanna Sandvig","doi":"10.1152/ajpcell.00725.2024","DOIUrl":"10.1152/ajpcell.00725.2024","url":null,"abstract":"<p><p>Amyotrophic lateral sclerosis (ALS) is characterized by dysfunction and loss of upper and lower motor neurons. Several studies have identified structural and functional alterations in the motor neurons before the manifestation of symptoms, yet the underlying cause of such alterations and how they contribute to the progressive degeneration of affected motor neuron networks remain unclear. Importantly, the short- and long-term spatiotemporal dynamics of neuronal network activity make it challenging to discern how ALS-related network reconfigurations emerge and evolve. To address this, we systematically monitored the structural and functional dynamics of motor neuron networks with a confirmed endogenous <i>C9orf72</i> mutation. We show that ALS patient-derived motor neurons display time-dependent neural network dysfunction, specifically reduced firing rate and spike amplitude, impaired bursting, but higher overall synchrony in network activity. These changes coincided with altered neurite outgrowth and branching within the networks. Moreover, transcriptional analyses revealed dysregulation of molecular pathways involved in synaptic development and maintenance, neurite outgrowth, and cell adhesion, suggesting impaired synaptic stabilization. This study identifies early synaptic dysfunction as a contributing mechanism resulting in network-wide structural and functional compensation, which may over time render the networks vulnerable to neurodegeneration.<b>NEW & NOTEWORTHY</b> RNA-sequencing of ALS patient-derived motor neurons revealed altered expression of genes involved in cell adhesion, neurite outgrowth, synaptic development and maintenance, and synaptic plasticity. These alterations were accompanied by time-dependent structural impairments and disrupted neuronal activity, suggesting that early synaptic changes and network-wide structural and functional compensations contribute to motor neuron vulnerability in ALS.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C1029-C1044"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142891412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"K_V7 channels modulate tension and calcium signaling in mouse corpus cavernosum.","authors":"Mitchell Mercer, Mark A Hollywood, Gerard P Sergeant, Keith D Thornbury","doi":"10.1152/ajpcell.00980.2024","DOIUrl":"10.1152/ajpcell.00980.2024","url":null,"abstract":"<p><p>Adrenergic stimulation induces contractions in the corpus cavernosum smooth muscle (CCSM), which are important in maintaining penile flaccidity. The aim of this study was to investigate the role of K_V7 channels in regulating contractions and their underlying Ca²⁺ signals in mouse CCSM. Quantitative PCR revealed transcriptional expression of <i>KCNQ1</i> and <i>KCNQ3-5</i> genes in the whole CCSM, with <i>KCNQ5</i> as the most highly transcribed K_V7-encoding gene. Immunocytochemistry in single CCSM myocytes confirmed expression of K_V7.5 protein. CCSM crura developed spontaneous phasic contractions in vitro that were inhibited by retigabine (RTG), a K_V7 channel opener, and potentiated by XE-991, a K_V7 channel blocker. The contractions were also blocked by nifedipine, confirming that they were dependent upon Ca²⁺ influx via L-type Ca²⁺ channels. Similarly, phenylephrine (PE) (0.3 µM) evoked phasic contractions that were inhibited and enhanced by RTG and XE-991, respectively. When a range of concentrations of PE (0.1-30 µM) was examined, both phasic and tonic contractions were observed, with phasic predominating at lower concentrations and tonic at higher concentrations. RTG inhibited only the phasic contractions, suggesting that these were dependent upon membrane potential but tonic contractions were not. In single-dispersed CCSM myocytes, spontaneous Ca²⁺ waves and Ca²⁺ waves induced by PE (0.1 µM) were inhibited by RTG or nifedipine and enhanced by XE-991. PE (10 µM) also induced Ca²⁺ waves but, similar to tonic contractions, these were resistant to inhibition with RTG or nifedipine. These findings have implications for targeting K_V7 channels in the treatment of erectile dysfunction.<b>NEW & NOTEWORTHY</b> Many men with ED are resistant to treatment with phosphodiesterase 5 inhibitors (e.g., sildenafil); therefore, new treatments are required. We show that spontaneous contractions and phasic contractions of CCSM induced by low/moderate concentrations of PE, and their underlying Ca²⁺ signals, are altered by K_V7 channel modulators, whereas tonic contractions and Ca²⁺ signals induced by high concentrations of PE are resistant to these compounds. This provides hope that K_V7 channels may be targeted to treat ED.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C729-C742"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142998415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of oral γ-aminobutyric acid intake on muscle regeneration in diabetic mice.","authors":"Mayu Horii, Chanikan Bumrungkit, Noriyuki Yanaka, Thomas J Hawke, Irena A Rebalka, Thanutchaporn Kumrungsee","doi":"10.1152/ajpcell.00963.2024","DOIUrl":"10.1152/ajpcell.00963.2024","url":null,"abstract":"<p><p>Though γ-aminobutyric acid (GABA) serves as the primary inhibitory neurotransmitter in the brain, its numerous biological activities in the periphery, including anti-inflammatory and antidiabetic functions, have been documented. In addition, GABA may be a mediator underlying effects of ketone bodies/ketogenic diets on muscle regeneration. Here, we investigated the effects of GABA on muscle regeneration in type 1 diabetes mouse models. Akita and wild-type (WT) mice were treated with GABA in drinking water for 6 wk, followed by cardiotoxin (CTX)-induced muscle injury. At 5 days postinjury, GABA treatment exhibited no effects on regenerating myofiber size in both WT and Akita mice. Unexpectedly, regenerating GABA-treated Akita muscles exhibited significantly increased embryonic myosin heavy chain (eMHC) expression and higher intramuscular macrophage content, suggesting delays in muscle regeneration and in elevated macrophage infiltration in diabetic muscles. Next, we determined if GABA treatment delayed the inflammatory process during muscle regeneration. Providing GABA in the drinking water during the peak inflammatory period (<i>days 0</i>-<i>5</i> postinjury) resulted in a significantly greater amount of small regenerating myofibers and higher expressions of TNFα and eMHC in regenerating streptozotocin (STZ)-diabetic muscles, indicating delays in inflammation process and muscle regeneration in diabetes. Plasma GABA levels were found higher in GABA-treated STZ mice than in WT mice and negatively correlated with regenerating myofiber size. This delay in muscle regeneration in STZ-diabetic mice was abolished by a lower dose of GABA water that did not raise plasma GABA levels. Together, high doses of GABA intake during the early phases of muscle repair may delay regeneration.<b>NEW & NOTEWORTHY</b> With increasing evidence that ketogenic diets improve aspects of muscle health (e.g., insulin sensitivity and mitochondrial function), we hypothesized that supplementation with GABA-a key metabolite changed with ketogenic diets-would improve muscle recovery from injury. Unexpectedly, GABA supplementation during the early inflammatory phases of muscle regeneration delayed muscle repair in type 1 diabetes mice, possibly due to inflammation suppression. Further work is needed to ascertain the effective use of GABA supplementation, particularly following intense or damaging exercise.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C967-C985"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143187661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estrogen deficiency alters vascularization and mineralization dynamics: insight from a novel 3-D humanized and vascularized bone organoid model.","authors":"Muhammad M M Bukhari, Mostafa Khabooshani, Syeda M Naqvi, Laoise M McNamara","doi":"10.1152/ajpcell.00738.2024","DOIUrl":"10.1152/ajpcell.00738.2024","url":null,"abstract":"<p><p>Osteoporosis is not merely a disease of bone loss but also involves changes in the mineral composition of the bone that remains. In vitro studies have investigated these changes and revealed that estrogen deficiency alters osteoblast mineral deposition, osteocyte mechanosensitivity, and osteocyte regulation of osteoclastogenesis. During healthy bone development, vascular cells stimulate bone mineralization via endochondral ossification, but estrogen deficiency impairs vascularization. Yet, existing in vitro bone models overlook the role of vascular cells in osteoporosis pathology. Thus, here we <i>1</i>) develop an advanced three-dimensional (3-D) vascularized, mineralized, and humanized bone model following the endochondral ossification process, and <i>2</i>) apply this model to mimic postmenopausal estrogen withdrawal and provide a mechanistic understanding of changes in vascularization and bone mineralization in estrogen deficiency. We confirmed the successful development of a vascularized and mineralized human bone model via endochondral ossification, which induced the self-organization of vasculature, associated with hypertrophy (collagen X), and promoted mineralization. When the model was applied to study estrogen deficiency, we reported the development of distinct vessel-like structures (CD31+) in the postmenopausal 3-D constructs. Moreover, during estrogen withdrawal vascularized bone demonstrated a significant increase in mineral deposition and apoptosis, which did not occur in nonvascularized bone. These findings reveal a potential mechanism for bone mineral heterogeneity in osteoporotic bone, whereby vascularized bone becomes highly mineralized whereas in nonvascularized regions this effect is not observed.<b>NEW & NOTEWORTHY</b> Here we develop an in vitro three-dimensional (3-D) vascularized and humanized bone model following an endochondral ossification approach. We applied the model to recapitulate estrogen deficiency as representative of the osteoporotic phenotype. The results of this study reveal that estrogen deficiency exacerbates formation of 3-D vessel-like structures in vascularized models and thereby drives mineral deposition.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C743-C756"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142998046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cdc42 is crucial for the early regulation of hepatic stellate cell activation.","authors":"Hideto Yuasa, Tsutomu Matsubara, Hayato Urushima, Atsuko Daikoku, Hiroko Ikenaga, Chiho Kadono, Masahiko Kinoshita, Kenjiro Kimura, Takeaki Ishizawa, Keisuke Ohta, Norifumi Kawada, Kazuo Ikeda","doi":"10.1152/ajpcell.00987.2024","DOIUrl":"10.1152/ajpcell.00987.2024","url":null,"abstract":"<p><p>The activation of hepatic stellate cells (HSCs) from a quiescent state is a cause of liver fibrosis and a therapeutic target. HSCs are resident mesenchymal cells located in the space of Disse, exhibiting specialized morphological characteristics such as a stellate shape, large lipid droplets, and direct adhesions to hepatocytes via microprojections called HSC spines. Morphological alterations in HSCs play a crucial role in initiating their activation. However, the mechanisms regulating these changes remain unexplored. In this study, we analyzed the morphological alterations associated with HSC activation in vivo using carbon tetrachloride treatment and identified the key factors regulating these changes in vitro. Following carbon tetrachloride treatment, HSCs exhibited shortened cell processes and HSC spines, adopting an oval shape. Subsequently, the HSCs underwent further morphological changes into two activated forms: flattened and complex shapes. In vitro, activation of cell division cycle 42 (Cdc42) maintained the morphological characteristics of quiescent HSCs. Cdc42 activation in HSC cell lines inhibited the expression of markers associated with activated HSCs. Cdc42 inhibitor treatment in vivo prevented quiescent HSCs from maintaining their morphological characteristics and hindered activated HSCs from reverting to the quiescent state. In addition, HSCs around fibrotic areas in the human liver exhibited morphological alterations indicative of early activation. These findings demonstrate that Cdc42 is a crucial regulator of morphological and molecular alterations associated with HSC activation, identifying it as a novel target for the development of therapeutic agents against liver fibrosis.<b>NEW & NOTEWORTHY</b> The activation of hepatic stellate cells from a quiescent state is a cause and a therapeutic target for liver fibrosis. Morphological alterations in the hepatic stellate cells play a critical role in initiating their activation. However, the mechanisms that regulate these alterations remain unexplored. Our results indicate that cell division cycle 42 is a crucial regulator of hepatic stellate cell activation and a novel target for the development of therapeutic agents against liver fibrosis.</p>","PeriodicalId":7585,"journal":{"name":"American journal of physiology. Cell physiology","volume":" ","pages":"C757-C775"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143051023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}