Histochemistry and Cell Biology最新文献

Intervertebral disc degeneration (IDD) is known as a primary contributor to low back pain, a debilitating condition which is the leading cause of disability worldwide. Traditionally, its assessment is based on clinical parameters, including magnetic resonance imaging (MRI). However, patients with similar radiological findings may have significantly different prognoses suggesting the involvement of patient-specific biomarkers and little-investigated molecules supporting the complexity of the pathophysiological microenvironment of the intervertebral disc (IVD). We conducted a study on IVD biopsies from 40 patients with mild IDD (Pfirrmann III), to identify a potential molecular signature that correlates with clinical and behavioral parameters including sex, age, smoking, body mass index (BMI), duration of symptoms prior to surgery, inflammatory cell density, or surgical site. Immunohistological analysis focused on the expression of proteins involved in the defense against oxidative stress, in the maintenance of IVD homeostasis, and energy metabolism: the transcription factors FOXO3a, HIF1α, Bry, the enzyme SOD2, and the glucose transporter GLUT1. Significant differences in protein expression were observed only in relation to Pfirrmann grade. Within the grade III subgroup, expression levels did not vary with patient-specific parameters or clinical outcomes such as complete healing, recurrence, or persistent pain after surgery. This highlights the importance of broadening the scope of assessment in pathological conditions such as IDD. Rather than limiting the evaluation to the expression level of a single protein marker, it is crucial to collect comprehensive data on the various factors that may influence individual patient responses to disc degeneration.

Skin aging is associated with fibroblast senescence, impaired wound healing, and dysregulation of markers such as sirtuin 1 (SIRT1) and fibroblast activation protein-α (FAP-α). It is known that proliferation and migration decrease in aging fibroblasts, which delays the repair process. Metformin, a widely used anti-diabetic drug, can regulate cellular senescence pathways. This study evaluated the effects of metformin on wound healing and SIRT1 and FAP-α expression in senescent fibroblasts. Cellular senescence was induced in primary human dermal fibroblasts using 100 µM hydrogen peroxide (H₂O₂), as validated by a WST-8 assay and SA-β-gal staining. Wound healing assay and immunocytochemistry were performed on control, senescent, and metformin-treated groups (2.5, 5, and 10 mM). Wound closure was significantly impaired in senescent fibroblasts (38% at 72 h versus 89% in the control group). Metformin restored wound healing in a dose-dependent manner; the 10 mM group achieved 94% closure at 72 h, which was comparable to the control group. SIRT1 expression decreased in senescent fibroblasts (90.17 ± 4.67 vs. 124.83 ± 4.31 in controls, p < 0.001) and increased progressively with metformin treatment, reaching control levels at 10 mM. FAP-α expression increased in senescent fibroblasts (91.83 ± 4.36 vs. 78.17 ± 2.56 in controls, p < 0.05) and declined towards baseline with metformin treatment, being significantly reduced at 5 and 10 mM. Metformin improved wound healing capacity and normalized age-related alterations in SIRT1 and FAP-α expression in senescent fibroblasts. These results imply that metformin alleviates senescence-associated dysfunction, suggesting its potential as a therapeutic agent to enhance wound repair in aging skin.

Histological changes in skeletal muscle after heart failure have been widely investigated in the lower limbs, including slow-to-fast fiber type transition, fast fiber-predominant atrophy, reduced capillary number, and increased collagen content. However, histological changes in the upper limb muscles remain largely unexplored. Given the prognostic significance of grip strength and upper limb muscle mass in heart failure, elucidating these changes is essential. We aimed to investigate histological changes in forelimb muscles in a rat model of monocrotaline (MCT)-induced heart failure. Rats were assigned to control (vehicle-injected) or heart failure (MCT-injected) groups. Grip strength was measured on day 27, and histological analyses of the biceps brachii (BiB) and flexor digitorum profundus (FDP) were performed on day 28. Grip strength significantly reduced in the heart failure group. Both BiB and FDP exhibited significant atrophy of fast fibers without changes in slow fiber size. The BiB showed a reduced capillary-to-muscle fiber ratio and no change in fiber type, whereas the FDP showed a shift toward a faster fiber phenotype and no change in capillary number. Collagen content remained unchanged in both muscles. MCT-induced heart failure leads to fast fiber-specific atrophy in forelimb muscles, with muscle-specific differences in capillary and fiber type adaptations. These changes may underlie the impaired upper limb muscle functions in heart failure. While some findings are consistent with those in lower limb muscles, others differ, suggesting region- and muscle-specific responses. Thus, findings from a single muscle cannot necessarily be extrapolated to all skeletal muscles.

One of the most frequent reasons behind respiratory failure is acute lung injury (ALI). In response to endoplasmic reticulum stress (ERS), the protein known as stimulator of interferon genes (STING) triggers strong lung inflammatory reactions and damage. The current study evaluated the possible influence of platelet-rich plasma (PRP) on ALI through altering the cyclic GMP-AMP synthase (cGAS)-triggered STING/ERS/TANK-binding kinase 1 (TBK1)/interferon regulatory factor 3 (IRF3)/nuclear factor kappa B (NF-κB) pathway. Twenty-one adult male Wistar rats were arbitrarily divided into three sets of seven: (1) control (CTRL); (2) ALI, in which the rats were given intraperitoneal (i.p.) lipopolysaccharide (LPS) at 10 mg/kg once; and (3) ALI + PRP, in which, at 1 week after i.p. LPS injection, rats were injected (i.p.) with PRP every 3 days for 4 weeks. At the end of the experiment, blood samples and lung tissues were evaluated at biochemical, molecular, and histological levels. PRP caused downregulation of the cGAS-induced STING/ERS/TBK1/IRF3/NF-κB signaling pathway and lessened lung inflammatory and apoptotic insults. This was evident on microscopic examination of lung tissue with significantly decreased immunoreactivity of lung tissue caspase 3, NF-κB, and tumor necrosis factor-alpha. PRP is a promising biological therapeutic regimen against ALI.

The thyroid gland is a unique endocrine organ, composed of morpho-functional units called thyroid follicles, which are responsible for thyroid hormone (TH) biosynthesis, an iodination process demanding a highly oxidative yet protected environment. Despite primary cilium (PC) being observed in the thyroid gland more than a century ago, its precise role in thyroid activity remains rather unexplored. Given its strategic position at the apical surface of follicular epithelium, projecting into the lumen, PCs are crucial for the regulation of TH biosynthetic processes. Consequently, changes in thyroid function, either physiological or pathological, are reflected in PC characteristics. Similarly, defects in ciliogenesis are expected to lead to different pathological thyroid alterations. This review summarizes the current understanding of PC's involvement in regulating normal thyroid activity and its modifications in functional and neoplastic thyroid diseases. Particular focus will be given to the notable loss of PCs in certain types of thyroid cancer and the promising potential of their restoration as a tumor suppressor strategy in thyroid tumorigenesis.

E-cadherin is a key determinant of epithelial tissue architecture, and its inhibition has been linked to transcriptional reprogramming and cellular plasticity in epithelial cancers. However, the chromatin-level mechanisms driving these changes remain incompletely understood. EP300, a histone acetyltransferase and transcriptional coactivator, has been implicated in mediating epigenetic responses to cell-cell adhesion loss. We examined the genome-wide chromatin binding profile of EP300 in MCF7 breast cancer cells following functional inhibition of E-cadherin using a neutralizing antibody. Chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) revealed 4128 EP300-enriched regions in control cells and 2943 in treated cells, with only 12 sites shared between conditions, indicating widespread redistribution. These changes localized to gene loci associated with epithelial identity (e.g., CDH1, CD46) and were replaced by increased occupancy at mesenchymal (CDH2, LOX) and pluripotency-associated loci (SEMA3E, MET). Differential binding was validated by chromatin immunoprecipitation coupled with quantitative polymerase chain reaction (ChIP-qPCR). Notably, EP300 protein levels remained unchanged, suggesting a redistribution rather than expression-level regulation. Our findings suggest that E-cadherin inhibition is associated with early changes in EP300 chromatin localization, particularly at loci linked to epithelial-mesenchymal transition (EMT) and pluripotency. These changes may reflect an early chromatin-level response to altered cell adhesion, warranting further functional investigation.

Humans are increasingly exposed to silica nanoparticles (SiNPs) from environmental and occupational sources, raising significant concerns about their safety. Despite growing applications, data on their neurotoxic effects, particularly those involving oxidative/nitrosative imbalance and striatal damage, remain limited. This study aimed to elucidate the mechanisms of SiNP-induced neurotoxicity in the striatum, a brain region crucial for motor control and learning, using a rat model. Subacute intraperitoneal administration of SiNPs (25 and 100 mg/kg bw/day for 28 days) resulted in a marked increase in lipid peroxidation (LPO), reactive oxygen species (ROS), nitrite (NO), and protein carbonyl content, alongside a significant reduction in the activity of antioxidant enzymes, viz. superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), as well as glutathione (GSH). Additionally, cholinergic [acetylcholinesterase (AChE) and b1utyrylcholinesterase (BChE)] and membrane-bound adenosine triphosphate (ATP)ase (Na⁺/K⁺, Mg²⁺, and Ca²⁺ ATPase) activities were significantly reduced in the striatum. Immunofluorescence and immunohistochemistry revealed elevated expression of antioxidant markers, particularly nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Quantitative reverse-transcriptase real-time polymerase chain reaction (qRT-PCR) analysis demonstrated upregulation of pro-apoptotic genes (Bax, p53, caspase-9/3) and downregulation of the anti-apoptotic gene Bcl-2, leading to an increased Bax/Bcl-2 ratio. Complementary in silico molecular docking studies showed that SiNPs exhibit notable binding affinities toward Nrf2, HO-1, AChE, and BChE. Collectively, these findings indicate that SiNPs induce striatal neurotoxicity via oxidative/nitrosative stress-mediated apoptosis, involving activation of Nrf2/HO-1, cholinergic disruption, and apoptotic signaling pathways.