Search Results (108)

Cardiovascular disease encompasses a wide group of conditions that affect the heart and blood vessels. Of these diseases, cardiomyopathies and arrhythmias specifically have been well-studied in their relationship to cardiac dyads, nanoscopic structures that connect electrical signals to muscle contraction. The proper development and positioning of dyads is essential in excitation–contraction (EC) coupling and, thus, beating of the heart. Three proteins, namely CMYA5, JPH2, and BIN1, are responsible for maintaining the dyadic cleft between the T-tubule and junctional sarcoplasmic reticulum (jSR). Various other dyadic proteins play integral roles in the primary function of the dyad—translating a propagating action potential (AP) into a myocardial contraction. Ca²⁺, a secondary messenger in this process, acts as an allosteric activator of the sarcomere, and its cytoplasmic concentration is regulated by the dyad. Loss-of-function mutations have been shown to result in cardiomyopathies and arrhythmias. Adeno-associated virus (AAV) gene therapy with dyad components can rescue dyadic dysfunction, which results in cardiomyopathies and arrhythmias. Overall, the dyad and its components serve as essential mediators of calcium homeostasis and excitation–contraction coupling in the mammalian heart and, when dysfunctional, result in significant cardiac dysfunction, arrhythmias, morbidity, and mortality. Full article

Background: During infection with the cytomegalovirus (CMV), the membrane system of the infected cell is remodelled into a megastructure called the assembly compartment (AC). These extensive changes may involve the manipulation of the host cell proteome by targeting a pleiotropic function of the cell such as ubiquitination (Ub). In this study, we investigate whether the Ub system is required for the establishment and maintenance of the AC in murine CMV (MCMV)-infected cells Methods: NIH3T3 cells were infected with wild-type and recombinant MCMVs and the Ub system was inhibited with PYR-41. The expression of viral and host cell proteins was analyzed by Western blot. AC formation was monitored by immunofluorescence with confocal imaging and long-term live imaging as the dislocation of the Golgi and expansion of Rab10-positive tubular membranes (Rab10 TMs). A cell line with inducible expression of hemagglutinin (HA)-Ub was constructed to monitor ubiquitination. siRNA was used to deplete host cell factors. Infectious virion production was monitored using the plaque assay. Results: The Ub system is required for the establishment of the infection, progression of the replication cycle, viral gene expression and production of infectious virions. The Ub system also regulates the establishment and maintenance of the AC, including the expansion of Rab10 TMs. Increased ubiquitination of WASHC1, which is recruited to the machinery that drives the growth of Rab10 TMs, is consistent with Ub-dependent rheostatic control of membrane tubulation and the continued expansion of Rab10 TMs. Conclusions: The Ub system is intensively utilized at all stages of the MCMV replication cycle, including the reorganization of the membrane system into the AC. Disruption of rheostatic control of the membrane tubulation by ubiquitination and expansion of Rab10 TREs within the AC may contribute to the development of a sufficient amount of tubular membranes for virion envelopment. Full article

To investigate thermal tolerance, physiological responses, and molecular mechanisms of the narrow-clawed crayfish (Pontastacus leptodactylus) under acute thermal stress, the P. leptodactylus were acutely exposed to 4 different temperature groups—15 °C (control), 20 °C (T20), 25 °C (T25), and 30 °C (T30)—across 6 time points (3 h, 6 h, 12 h, 24 h, 48 h, and 72 h). Survival rates were recorded at each interval. Subsequent analyses comprised: (1) Hemolymph biochemical parameter determination; (2) hepatopancreatic antioxidant capacity assessment; (3) hepatopancreatic histopathology; and (4) comparative transcriptomics analysis of the hepatopancreas. The results showed that the survival rate in the T30 group significantly declined after 48 h of stress. The histological analysis of the hepatopancreas revealed tissue damage in both the T25 and T30 groups. The T25 group exhibited a notable increase in B-cell density and severe vacuolization, while the T30 group displayed disorganized hepatopancreatic cell arrangement, marked necrosis, and structural phenotypes in hepatopancreatic tubules, including lumen expansion and the loss of the star-shaped lumen structure. Biochemical analyses indicated pronounced declines in energy metabolism markers under elevated temperatures. Furthermore, the T30 group exhibited elevated levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT), alongside diminished total antioxidant capacity (T-AOC). Similarly, the T25 group displayed increased MDA and CAT levels but decreased T-AOC. Comparative transcriptomic analysis demonstrated that differentially expressed genes (DEGs) in the control vs. T25 group were predominantly enriched in metabolic pathways, whereas DEGs identified in control vs. T30 and T25 vs. T30 comparisons showed significant enrichment in energy metabolism and apoptotic processes. Based on these findings, we concluded that acute thermal stress induces mortality in P. leptodactylus through hepatopancreatic structural damage, energy metabolism dysregulation, and excessive ROS accumulation. Notably, P. leptodactylus should be excluded from aquaculture environments exceeding 25 °C. These results enhance understanding of the adaptive mechanisms of P. leptodactylus under acute thermal stress and provide actionable insights to advance its industrial cultivation. Full article

Enterococcus faecalis (E. faecalis) is a major pathogen responsible for refractory apical periodontitis (RAP). It can penetrate deep into dentinal tubules, form persistent biofilms, and exhibit antibiotic resistance, thereby limiting the efficacy of conventional antimicrobial treatments. Bacteriophages (phages), due to their strong lytic activity and host specificity, have emerged as promising alternatives. In this study, a novel strictly lytic phage, ZXL-01, was isolated from lake water in Jilin, China. ZXL-01 demonstrated remarkable stability under extreme conditions, including thermal tolerance at 60 °C for 1 h and a wide pH range (4–11). Whole-genome sequencing (GenBank accession number: ON113334) revealed a genome of 40,804 bp with no virulence or tRNA genes, confirming its identity as an E. faecalis phage. Importantly, ZXL-01 exhibited potent antibiofilm activity, reducing biofilm biomass by approximately 69.4% in the inhibition group and 68.4% in the lysis group (both p < 0.001). In an in vitro root canal infection model induced by E. faecalis, scanning electron microscope (SEM) observations confirmed that ZXL-01 effectively inhibited biofilm formation and disrupted mature biofilms. These findings highlight the potential of ZXL-01 as a novel antimicrobial agent for the treatment of E. faecalis-associated apical periodontitis. Full article

The L-type calcium channels (LTCCs) function as the main entry points that convert myocyte membrane depolarization into calcium transients, which drive every heartbeat. There is increasing evidence to show that maladaptive remodeling of these channels is the cause of heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). Recent experimental, translational, and clinical studies have improved our understanding of the roles LTCC expression, micro-domain trafficking, and post-translational control have in disrupting excitation–contraction coupling, provoking arrhythmias, and shaping phenotype specific hemodynamic compromise. We performed a systematic search of the PubMed and Google Scholar databases (2015–2025, English) and critically evaluated 17 eligible publications in an effort to organize the expanding body of work. This review combines existing data about LTCC density and T-tubule architecture with β-adrenergic and Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) signaling and downstream sarcoplasmic reticulum crosstalk to explain how HFrEF presents with contractile insufficiency and how HFpEF shows diastolic calcium overload and stiffening. Additionally, we highlight the emerging therapeutic strategies aimed at restoring calcium homeostasis such as CaMKII inhibitors, ryanodine receptor type 2 (RyR2) stabilizers, and selective LTCC modulators without compromising systolic reserve. The review establishes LTCC dysregulation as a single mechanism that causes myocardial dysfunction while remaining specific to each phenotype, thus offering clinicians and researchers a complete reference for current concepts and future precision therapy approaches in heart failure. Full article

As an emerging endocrine-disrupting agent and structural analog of bisphenol A (BPA), bisphenol B (BPB) raises significant concerns due to its potential to induce male reproductive toxicity. Despite its presence in maternal bodily fluids, the effects of BPB exposure on the reproductive system and its mechanisms in adult male offspring are poorly understood. By establishing a maternal BPB exposure model in mice, we found that the exposure reduced the relative weights of seminal vesicles and preputial glands, decreased the thickness of the seminiferous epithelium, enlarged the lumen area of seminiferous tubules, and lowered testosterone concentration and synthesis, as well as sperm count in 10-week-old male offspring. Bioinformatic analyses revealed that the differentially expressed genes were significantly associated with major histocompatibility complex I (MHC I)-mediated immunological processes, including immune system processes, antigen processing and presentation of exogenous peptide antigens via MHC class I, and interleukin-2 production. Importantly, molecular docking proposed a potential mechanistic model wherein BPB bound to estrogen receptor α (ERα) suppressed its testicular expression and triggered MHC class I gene overexpression, potentially promoting macrophage infiltration, CD4+/CD8+ T cell activation, and pro-inflammatory cytokine production. Our findings provide critical insights into the adverse effects of maternal BPB exposure on male reproductive development, suggesting that impairments in testicular morphology and spermatogenesis may be attributed to MHC I-mediated immunological responses and hormonal imbalances resulting from inhibited ERα signaling. These results underscore not only the toxicological risks associated with BPB but also potential therapeutic targets for mitigating male reproductive dysfunction. Full article

Diabetes mellitus has been knowingly associated with increased risk of fractures, so much so that skeletal fragility is considered a complication of diabetes. Determinants of bone fragility in this chronic condition are several, and the diabetes treatment choice could influence bone metabolism. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have recently expanded the therapeutic armamentarium for type 2 diabetes mellitus (T2D); these antihyperglycemic drugs act by reducing renal glucose reabsorption in the proximal tubule and have a proven cardiorenal benefit. The role of SGLT2i towards phospho-calcium metabolism is still unclear, so we aimed to review the current evidence of the relationship between SGLT2i and calcium and phosphate homeostasis. The PubMed, Scopus, and Web of Knowledge databases were searched to identify original research articles, meta-analyses, and scientific reviews on effects on bone metabolism in T2D patients treated with SGLT2i. Emerging data indicate that SGLT2i may lead to a rise of bone turnover markers, promoting a lower skeletal bone density and an increased fracture risk on murine models, but in real-world studies, results are controversial. Therefore, more clinical trials are needed to further clarify this topic, and the effects of SGLT2i on calcium homeostasis remain to date poorly understood. Full article

Primary mouse renal proximal tubule epithelial cells (moRPTECs) were immortalized by lentivirus transduction to create hTERT or SV40LgT (LgT) cell lines. Prior work showed a more pronounced injury and repair response in LgT versus hTERT cells after chemical challenge. We hypothesized that unique genomic changes occurred after immortalization, altering critical genes and pathways. RNA-seq profiling and whole-genome sequencing (WGS) of parent, hTERT, and LgT cells showed that 92.5% of the annotated transcripts were shared, suggesting a conserved proximal tubule expression pattern. However, the cell lines exhibited unique transcriptomic and genomic profiles different from the parent cells. Three transcript classes were quite relevant for chemical challenge response—Cyps, ion channels, and metabolic transporters—each important for renal function. A pathway analysis of the hTERT cells suggested alterations in intermediary and energy metabolism. LgT cells exhibited pathway activation in cell cycle and DNA repair that was consistent with replication stress. Genomic karyotyping by combining WGS and RNA-seq data showed increased gene copy numbers in chromosome 5 for LgT cells, while hTERT cells displayed gene copy losses in chromosomes 4 and 9. These data suggest that the exaggerated transcriptional responses of LgT cells versus hTERT cells result from differences in gene copy numbers, replication stress, and the unique selection processes underlying LgT or hTERT immortalization. Full article

Spermatogenesis is a process of self-renewal of spermatogonial stem cells and their proliferation and differentiation to generate mature sperm. This process involves interactions between testicular somatic (mainly Sertoli cells) and spermatogonial cells at their different stages of development. The functionality of Sertoli cells is regulated by hormones and testicular autocrine/paracrine factors. In this study, we investigated the effects of follicle-stimulating hormone (FSH) and testosterone addition on Sertoli cell cultures that undergo hypotonic shock, with a primary focus on Sertoli cell activity. Cells were enzymatically isolated from testicular seminiferous tubules of 7-day-old mice. These cells were cultured in vitro for 3 days. Thereafter, some cultures were treated with hypotonic shock to remove germ cells. After overnight, fresh media without (control; CT) or with FSH, testosterone (Tes), or FSH+T were added to the hypotonic shock-treated or untreated (CT) cultures for 24 h. The morphology of the cultures and the presence of Sertoli cells and germ cells were examined. The expression of growth factors (CSF-1, LIF, SCF, GDNF) or other specific Sertoli cell factors [transferrin, inhibin b, androgen receptor (AR), androgen binding protein (ABP), FSH receptor (FSHR)] was examined by qPCR. Our immunofluorescence staining showed depletion/major reduction in VASA-positive germ cells in Sertoli cell cultures following hypotonic shock (HYP) treatment compared to untreated cultures (WO). Furthermore, the expression of the examined growth factors and other factors was significantly increased in HYP cultures compared to WO (in the CT). However, the addition of hormones significantly decreased the expression levels of the growth factors in HYP cultures compared to WO cultures under the same treatment. In addition, the expression of all other examined Sertoli cell factors significantly changed following HYP treatment compared to WO and following treatment with FSH and or T. However, the expression levels of some factors remained normal following the treatment of Sertoli cell cultures with one or both hormones (transferrin, Fsh-r, Abp, Ar). Thus, our results demonstrate the crucial role of germ cells in the functionality of Sertoli cells and the possible role of FSH and T in maintaining, at least partially, the normal activity of Sertoli cells following germ cell depletion in vitro by hypotonic shock treatment. Full article

CD133+CD24+ renal tubular progenitor cells play a crucial role in the repair and regeneration of renal tubules after acute kidney injury. The aim of this study is to investigate the responses of the human renal tubular precursor TERT (HRTPT) CD133+CD24+ cells and human renal epithelial cell 24 TERT (HREC24T) CD133-CD24+ cells to hypoxic stress, as well as their gene expression profiles. Whole transcriptome sequencing and functional network analysis identified distinct molecular characteristics of HRTPT cells as they were enriched with hypoxia-inducible factor-1A (HIF1A), epidermal growth factor (EGF), and endothelin-1 (EDN1). Our in vitro experiments demonstrated that, under hypoxia (2.5% oxygen), HRTPT cells showed minimal cell death and a 100-fold increase in HIF1A protein levels. In contrast, HREC24T cells exhibited significant cell death and only a two-fold increase in HIF1A protein level. These results indicate that CD133+CD24+ renal tubular progenitor cells have enhanced survival mechanisms under hypoxic stress, enabling them to survive and proliferate to replace damaged tubular cells. This study provides novel insights into the protective role of CD133+CD24+ renal tubular progenitor cells in hypoxic renal injury and identifies their potential survival mechanisms. Full article

Background/Objectives: The pathogenesis of diabetic kidney disease (DKD) is complex and multifactorial. Because of its complications and reduced number of diagnostic biomarkers, it is important to explore new biomarkers with possible roles in the early diagnosis of DKD. Our study aims to investigate the pattern of previously identified metabolites and their association with biomarkers of endothelial dysfunction, proximal tubule (PT) dysfunction, and podocyte injury. Methods: A total of 110 participants, comprising 20 healthy individuals and 90 patients divided in three groups were enrolled in the study: normoalbuminuria, microalbuminuria, and macroalbuminuria. Untargeted and targeted metabolomic methods were employed to assess urinary and serum biomarkers, as well as indicators of endothelial dysfunction, podocyte damage, and PT dysfunction through ELISA techniques. Results: Our research uncovered specific metabolites that exhibit varying levels across different sub-groups. Notably, glycine serves as a distinguishing factor between group C and the normoalbuminuric group. Furthermore, glycine is correlated with endothelial markers, especially VCAM. We observed a gradual decrease in kynurenic acid levels from group C to group P3; this biomarker also demonstrates an inverse relationship with both p-selectin and VCAM. Additionally, tryptophan levels decline progressively from group C to group P3, accompanied by a negative correlation with p-selectin and VCAM. Urinary tiglylglycine also differentiates among the patient groups, with concentrations decreasing as the condition worsens. It shows a strong positive correlation with nephrin, podocalyxin, KIM1, and NAG. Conclusions: In conclusion, glycine, tiglylglycine, kynurenic acid and tryptophan may be considered putative biomarkers for early diagnosis of DKD and T2DM progression. Full article

The kidney plays an essential role in the proper homeostasis of glucose. In the kidney, glucose transport is carried out across cell membranes by two families of glucose transporters—facilitated diffusion glucose transporters (GLUTs) and Na(+)-dependent glucose co-transporters (SGLT family). Among the transporters, sodium-dependent glucose co-transporters play a major role in the kidney‘s ability to reabsorb glucose. Although the localization of glucose transporters has been extensively studied in mammals, there are still knowledge gaps regarding the localization of SGLTs in birds. The aim of this research was to conduct a comparative study of the immunolocalization of the sodium-dependent glucose co-transporters SGLT1 and SGLT2 in the kidneys of healthy and T-2-mycotoxicated chickens. Immunohistochemical staining was carried out using the polyclonal primary antibodies SGLT1 and SGLT2 (Abcam, UK) in kidney tissue derived from seven healthy and seven T-2-mycotoxicated 7-day-old female layer-type Ross chickens (Gallus gallus domesticus). The sections were stained using an immunohistochemistry kit (Abcam, UK). In the kidneys of the healthy birds, strong staining of SGLT1 and SGLT2 was observed in the cytoplasm of the epithelial cells of the proximal straight and convoluted tubules. In the kidneys of the birds of the T-2 toxin group, weak expression of SGLT1 and SGLT2 with morphological changes occurred, indicating reduced glucose transport in the urinary system during T-2 mycotoxicosis. Full article

Type 2 diabetes mellitus (T2DM), accounting for the majority of diabetes mellitus prevalence, is associated with an increased risk of cognition decline and deterioration of cognition function in diabetic patients. The sodium–glucose cotransporter 2 (SGLT2), located in the renal proximal tubule, plays a role in urine glucose reabsorption. SGLT2 inhibitors (SGLT2i), have shown potential benefits beyond cardiac and renal improvement in preventing and treating cognitive impairment (CI), including mild cognitive impairment, Alzheimer’s disease and vascular dementia in T2DM patients. Studies suggest that SGLT2i may ameliorate diabetic CI through metabolism pathways, inflammation, oxidative stress, neurotrophic factors and AChE inhibition. Clinical trials and meta-analyses have reported significant and insignificant results. Given their vascular effects, SGLT2i may offer unique protection against vascular CI. This review compiles mechanisms and clinical evidence, emphasizing the need for future analysis, evaluation, trials and meta-analyses to verify and recommend optimal SGLT2i selection and dosage for specific patients. Full article

There is no doubt that the proper development of the heart is important for its correct function, in addition, maturation processes of the heart are crucial as well. The actin-binding protein nexilin seems to take over central roles in the latter processes, as nexilin-deficient mice are phenotypically inconspicuous at birth but die within short time thereafter. Recently, it has been proposed that nexilin plays a role in the formation and function of transverse tubules (T-tubules), which are essential for excitation-contraction coupling in the hearts of mature animals. Although it has long been known that nexilin is subjected to alternative splicing, a molecular characterization of the respective isoforms is not yet available. Here, we describe novel nexilin splice variants and analyze their expression in tissues of mice and humans. Interestingly, nexilin isoforms segregate to myocyte- and epithelial-specific isoforms. Moreover, heart-specific isoforms of nexilin localize differently between atria and ventricles and are also expressed in the endothelial cells of blood vessels. Further, we narrowed down the critical exons in the actin-binding domains 1 and 2 (ABD1/2), and observed different self-interaction properties by recombinant protein interaction studies. Our results emphasize the diverse tissue and subcellular distribution of the individual nexilin isoforms and point to the importance of taking a closer look at the particular nexilin isoforms investigated. Full article

The developmental changes in the excitation–contraction mechanisms of the ventricular myocardium of small animals (guinea pig, rat, mouse) and their sympathetic regulation will be summarized. The action potential duration monotonically decreases during pre- and postnatal development in the rat and mouse, while in the guinea pig it decreases during the fetal stage but turns into an increase just before birth. Such changes can be attributed to changes in the repolarizing potassium currents. The T-tubule and the sarcoplasmic reticulum are scarcely present in the fetal cardiomyocyte, but increase during postnatal development. This causes a developmental shift in the Ca²⁺ handling from a sarcolemma-dependent mechanism to a sarcoplasmic reticulum-dependent mechanism. The sensitivity for beta-adrenoceptor-mediated positive inotropy decreases during early postnatal development, which parallels the increase in sympathetic nerve innervation. The alpha-adrenoceptor-mediated inotropy in the mouse changes from positive in the neonate to negative in the adult. This can be explained by the change in the excitation–contraction mechanism mentioned above. The shortening of the action potential duration enhances trans-sarcolemmal Ca²⁺ extrusion by the Na⁺-Ca²⁺ exchanger. The sarcoplasmic reticulum-dependent mechanism of contraction in the adult allows Na⁺-Ca²⁺ exchanger activity to cause negative inotropy, a mechanism not observed in neonatal myocardium. Such developmental studies would provide clues towards a more comprehensive understanding of cardiac function. Full article