American journal of physiology. Cell physiology最新文献

The onset, development and progression of cancer are greatly influenced by the microenvironmental cues originating from diverse elements within the tumor niche. Extracellular matrix (ECM), the complex and dynamic macromolecular 3D network, governs cell functionality and play key roles in tumor growth and spreading. This article highlights the significance of ECM-based bioscaffolds in providing a relevant microenvironment not only for studying tumor behavior and drug efficacy but also for narrowing the gap between translational cancer research and targeted cancer treatment. The development of novel and user-friendly platforms that resemble the human tumor microenvironment in early and advanced cancer stages, may help to predict treatment response, thus facilitating the development and testing of new drugs, bridging the gap between in vitro and in vivo models. Additionally, we present innovative strategies leveraging ECM bioscaffolds for personalized cancer treatment, including drug delivery systems and tissue engineering approaches. Specific case studies as well as ethical concerns related to the use of ECM bioscaffolds in research and therapy are also presented and critically discussed. By elucidating the intricate interplay between ECM and cancer biology, this article underscores the potential of ECM bioscaffolds as novel platforms for shaping future therapeutic interventions and advancing precision oncology.

Parkinson's disease (PD) is an age-related neurodegenerative disorder. The pathological feature of PD is abnormal α-synuclein (α-syn) formation and transmission. Recent evidence demonstrates that α-syn preformed fibrils (α-syn PFFs) can be detected in the serum of patients with PD. The peripheral blood α-syn PFF can cross the blood-brain barrier (BBB) and aggravate neuronal damage, but the mechanism remains to be elucidated. We constructed the PD mouse models of different severity: the mild pathology (A53T ONLY) and the severe pathology (A53T + Brain FIB); this was followed by α-syn PFFs intravenous injection. Then, we used endothelium-specific Lag3 knockout mice (Lag3-ECs-CKO) to decrease the blood α-syn PFFs spreading. We observed that intravenous transmission of α-syn PFFs significantly aggravated motor deficits, dopaminergic neuron loss, neuroinflammation, and pathologic α-syn deposition in A53T ONLY, but not in A53T + Brain FIB. Blocking endothelial Lag3 endocytosis by Lag3-ECs-CKO decreased the blood α-syn PFFs spreading and improved the symptoms and pathogenesis of PD mice. Our findings reveal the role of peripheral blood α-syn PFFs transmission in the mild pathology or early-stage PD and the mechanism of endothelial Lag3 endocytosis in the pathology of α-syn transmission. Targeting endothelial Lag3 to prevent α-syn from spreading from the blood to the brain may be a disease-modifying therapy in early-stage PD.NEW & NOTEWORTHY This study highlights the transmission mechanism of peripheral blood α-synuclein preformed fibrils (α-syn PFFs) through endothelial Lag3 endocytosis in the mild pathology or early-stage Parkinson's disease (PD). Targeting endothelial Lag3 as a perspective of decreasing peripheral blood α-syn PFFs transmission may be a disease-modifying therapy in early-stage PD.

Most patients with lung cancer experience cancer cachexia (CC), a syndrome of skeletal muscle and adipose tissue wasting. Knowledge of body composition changes in patients is limited, however, because most studies have been cross-sectional, comparing patients with noncancer controls or patients with and without CC. Few studies, in contrast, have evaluated body composition in patients with lung cancer over time. This review examines our current understanding of longitudinal body composition changes in patients with lung cancer and identifies modifying factors contributing to variation in muscle and adipose tissue wasting, focusing on biological sex. We identified 32 studies conducting longitudinal measurements of body composition by computed tomography, bioelectrical impedance, dual X-ray absorptiometry, or total body nitrogen, with a total of n = 3,951 patients (35% female). All studies evaluated changes following diagnosis while patients were receiving treatment. Most studies reporting muscle-specific outcomes show decreased skeletal muscle mass, with more pronounced muscle wasting in males and male-enriched populations. In a small number of studies reporting muscle density, the majority show increased myosteatosis. Adiposity changes are less frequently reported, although wasting appears more prevalent in late-stage disease. Further studies are needed to define adipose changes along the lung cancer continuum. Our review emphasizes the need for balanced recruitment based on biological sex and sex-based analyses. In addition, consensus reporting of relevant patient data and outcomes in future studies will allow for meta-analysis and assist in the development of effective treatments for lung CC.

Overreaching (OR) can be defined as a decline in physical performance resulting from excessive exercise training, necessitating days to weeks recovery. Impairments in the contractile function of skeletal muscle are believed to be a primary factor contributing to OR. However, the cellular mechanism triggering OR remains unclear. The purpose of this study was to elucidate the mechanisms underlying OR. Rats' plantar flexor muscles were subjected to repeated electrical stimulations mimicking excessive high-intensity interval training (HIIT) daily for 13 consecutive days, and isometric torques were monitored. The torque was measured one day after HIIT, and subsequently, the physiological function of type II fibers was analyzed by using mechanically skinned-fiber technique. Eleven of 17 rats exhibited torque decline, whereas others did not. Thus, the rats were divided into OR and nonoverreaching (NOR) groups. Skinned fibers from the gastrocnemius (GAS) muscles of both groups showed decreased depolarization-induced force and increased myofibrillar Ca²⁺ sensitivity. However, the fibers from the OR group, but not the NOR group, exhibited a decrease in myofibrillar maximal force. Biochemical analyses of a superficial region of GAS muscle revealed that α-actinin 2 content was increased in the NOR group, but not in the OR group, whereas calpain-3 autolysis was increased in the OR group, but not in the NOR group. These findings shed light on the cellular mechanism underlying OR: OR following excessive HIIT was induced by a decreased myofibrillar maximal force, whereas Ca²⁺ sensitivity was increased.NEW & NOTEWORTHY An early sign of overtraining is a performance impairment known as overreaching (OR). This study revealed the cellular mechanism underlying OR by combining in vivo fatiguing contractions with mechanically skinned-fiber technique. Thirteen consecutive days of intense training result in myofibrillar force depression in OR. This study provides valuable insights not only for athletes and coaches but also for nonathletes who incorporate exercise into their daily activity.

β-O-linked-N-acetylglucosamine (O-GlcNAcylation) is a post-translational modification (PTM) characterized by the covalent attachment of a single moiety of N-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 O-GlcNAcylation and phosphorylation of TH at serine 40 (TH pSer40). First, we showed that, during PC12 cells neuritogenesis, TH O-GlcNAcylation decreases concurrently with the increase of pSer40. In addition, an increase in O-GlcNAcylation induces a decrease in TH pSer40 only in undifferentiated PC12 cells, whereas the decrease in O-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 O-GlcNAcylation is much more effective on TH pSer40 regulation than increasing its levels. Finally, ex vivo analysis confirmed the upregulation of TH pSer40 when O-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 O-GlcNAcylation and phosphorylation at Ser40 in TH.NEW & NOTEWORTHY This study shows how β-O-linked-N-acetylglucosamine (O-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.

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.NEW & NOTEWORTHY 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.

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 HAS2. 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 Has2 mRNA and concomitant accumulation of hyaluronan >1 MDa in size. Deletion of Has2 abrogated TGFβ-induced production of hyaluronan. In addition, overexpression of Has2 was sufficient to cause an increase in hyaluronan accumulation in the absence of TGFβ-induced activation. Our data indicated negligible impacts of Has2 on proliferation, migration, and collagen production. Exposing fibroblasts to exogenous hyaluronan also had minimal impact on fibroblasts. We also assessed whether fibroblast-borne Hyal2 plays a role in the degradation of hyaluronan, and our data indicated little impact of Hyal2 on hyaluronan accumulation (or even any impacts on the transcriptional profile of fibroblasts). Activated fibroblasts produce high-molecular-weight hyaluronan via Has2, which occurs independent of other fibroblast functions.NEW & NOTEWORTHY 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.

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.NEW & NOTEWORTHY 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.

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 KCNQ1 and KCNQ3-5 genes in the whole CCSM, with KCNQ5 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.NEW & NOTEWORTHY 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.

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 (days 0-5 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.NEW & NOTEWORTHY 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.