Cellular Physiology and Biochemistry最新文献

Metastasis, like carcinogenesis, involves the disruption of homeostasis such that cancer cells travel from the primary tumor to distant parts of the body. Almost all cancer deaths are due to metastatic spread. The prevailing theory of metastasis is an incomplete doctrine and far from sufficient as only 0.2% of free cancer cells result in the spread of cancer. To develop reasonable and effective cancer therapies and to prevent (or reverse) carcinogenesis and metastasis, a comprehensive understanding of how both carcinogenesis and metastasis arise is necessary. Fundamental questions in cancer biology have been asked and answered over decades of research: How do most cancers develop (Epistemology of the Origin of Cancer I, 2014-2022)? Which is the first cancer cell (II, 2023)? The third basic question in cancer biology remaining to be addressed is: What are the fundamentals of how metastasis develops? The pre-cancerous niche (PCN) that forms during carcinogenesis is altered by ongoing complex signaling into a premetastatic niche 1 (PMN-1): p130(cas)/crk/DOCK180 formation is necessary for lamellipodia formation, thereby enabling cell mobility. Cancer-associated fibroblasts (CAFs) begin to release fibronectin CXCL12 and Keratin 19. PMN-1 is transformed into PMN-2 during ongoing crosstalk and transformation of anti- into pro-tumorigenic platelets, macrophages, and neutrophils. Finally, persistent signaling and immune evasion result in the conversion of PMN-2 to PMN-3 with heterogeneous cancer satellites - the term "satellite" is used herein in accordance with its original meaning (a cell or particle escorting another). PMN-3 serves as a prerequisite for intravasation, traveling, and dissemination of cancer cells away from the primary tumor. Eight heterogeneous cancer satellites, including Trojan horses (immune evasion), travel alone or in combination: (1) cancer cells and (2) CAFs migrate along the CXCL12 and fibronectin gradient; (3) cancer cells surrounded by CAFs are shielded from the immune system and travel away from the primary cancer; (4) CXCL12 and Keratin 19 coat cancer cells; (5) platelets surround cancer cells and (6) CAFs, thereby facilitating cancer spread; and (7) neutrophil extracellular traps shield cancer cells and (8) CAFs. Metastasis in epithelial cancer occurs in parallel with carcinogenesis after the pre-cancerous niche is transformed into pre-metastatic niches (PMNs), which are indispensable to the origin of metastasis. Eight heterogeneous cancer satellites, including Trojan horses responsible for immune evasion, alongside reciprocally affecting sequences, wander alone or in conjunction with other cancer cells. This elucidates why the current practice of multimodal anti-cancer cell therapy should now be seen in a new light in which the benefits depend not on direct cancer cell effects, but on indirect cytopenic effects, which have previously been regarded merely as adverse effects.

Background/aims: Potassium channels regulate membrane potential, calcium flux, cellular activation and effector functions of adaptive and innate immune cells. The voltage-activated Kv1.3 channel is an important regulator of T cell-mediated autoimmunity and microglia-mediated neuroinflammation. Kv1.3 channels, via protein-protein interactions, are localized with key immune proteins and pathways, enabling functional coupling between K+ efflux and immune mechanisms.

Methods: To gain insights into proteins and pathways that interact with Kv1.3 channels, we applied a proximity-labeling proteomics approach to characterize protein interactors of the Kv1.3 channel in activated T-cells. Biotin ligase TurboID was fused to either N or C termini of Kv1.3, stably expressed in Jurkat T cells, and biotinylated proteins in proximity to Kv1.3 were enriched and quantified by mass spectrometry.

Results: We identified over 1,800 Kv1.3 interactors including known interactors (beta-integrins, Stat1), although the majority were novel. We found that the N-terminus of Kv1.3 preferentially interacts with protein synthesis and protein trafficking machinery, while the C-terminus interacts with immune signaling and cell junction proteins. T-cell Kv1.3 interactors we found consisted of 335 cell surface proteins, including T-cell receptor complex, mitochondrial, calcium and cytokine-mediated signaling pathway, and lymphocyte migration proteins. 178 Kv1.3 interactors in T-cells also represent genetic risk factors for T cell-mediated autoimmunity, including STIM1, which was further validated using co-immunoprecipitation.

Conclusion: Our studies revealed novel proteins and molecular pathways that interact with Kv1.3 channels in adaptive (T-cell) and innate (microglia) immune cells, providing a foundation for understanding how Kv1.3 channels may regulate immune mechanisms in autoimmune.

The interaction between the immune and cardiovascular systems is a growing field of investigation with bidirectional aspects. B cells are modulators of the adaptive and the innate immunity and they orchestrate bone marrow and spleen immune responses beyond infectious diseases. B cell regulation contributes to the pathophysiology of myocardial damage in several conditions including myocardial infarction, heart failure and atherosclerosis. In parallel, B cell-derived hematological disorders are interlinked to cardiovascular complications, including thrombosis and immunoglobulin-related cardiotoxicity. The scope of this review is to summarize the function and role of B cells as important players in myocardial and vascular adaptations to injury and as mediators of cardiovascular adverse events in hematological disorders. The primary focus is to highlight the clinical and preclinical findings regarding B cell-targeted therapies and their positive or negative impact on the cardiovascular system. A deeper understanding of B cell subpopulations, functions, and secretome could lead to targeted therapeutic interventions for cardiovascular and hematologic diseases.

Background/aims: Isobutylparaben (IBP) and phenylmercuric acetate (PMA) are extensively applied in pharmaceuticals, cosmetics, and industrial chemicals, and are of concern for developmental toxicity. This study was conducted to compare and assess the subchronic effects of IBP and PMA on growth, neurobehavior, reproduction, and organ integrity in juvenile female rats, and establish no-observed-adverse-effect levels (NOAELs).

Methods: Juvenile female Sprague-Dawley rats (n=10/group) were given IBP (10, 20, 50 mg/kg/day) or PMA (2, 4, 8 mg/kg/day) by gavage for 70 days. Assays encompassed growth assessment, onset of puberty (vaginal opening), estrous cyclicity (vaginal smears), neurobehavioral examination (open-field activity, sensory reflexes, grip strength, motor activity), haematology, serum biochemistry, thyroid hormones (ELISA), organ weights, and histopathology of reproductive, hepatic, and renal tissues.

Results: IBP and PMA at high doses significantly inhibited terminal body weight, postponed vaginal opening, disrupted motor function, and affected exploratory behavior. Biochemical indicators revealed hepatic and renal stress and histological findings of hepatocellular hypertrophy and renal tubular degeneration. PMA was somewhat more toxic. NOAELs were 20 mg/kg/day (IBP) and 4 mg/kg/day (PMA).

Conclusion: Both IBP and PMA caused dose-dependent developmental toxicity, calling for more stringent pediatric exposure evaluations and chemical safety regulations.

Impermeability of the ascending limb of the Henle loop for water is traditionally regarded as essential for countercurrent multiplication in the kidney. Similar claims have been made about permeability properties of the collecting duct and some other epithelia. It is not clear, however, how a structure based on phospholipid bilayers can be water-impermeant if phospholipid bilayers themselves have measurable permeability. The presence of two membranes separated by the cytoplasm may only account for a several-fold reduction in permeability compared to a single bilayer. By analyzing published data, we conclude that these tubules do have a finite water permeability, especially the collecting duct. Although the results on isolated ascending limbs vary among authors, osmotic shock experiments clearly indicate that both the collecting duct and the ascending Henle loop are sufficiently water-permeable to observe volume regulation effects. We conclude that these epithelia by themselves do not display unusual resistance to water flow; it can be estimated that 20-50% of the fluid entering the tubules can be reabsorbed into a strongly hypertonic medulla. It is possible, however, that unstirred layers in the intact kidney may contribute to the apparent low permeability of the tubules.

Background/aims: Endothelial cell senescence is a key contributor to the development of vascular pathologies, including arterial hypertension. Uric acid has been shown to promote oxidative stress and inflammation, thereby accelerating endothelial dysfunction and senescence. Although xanthine oxidase inhibition with allopurinol has demonstrated cardiovascular benefits, its effect on endothelial senescence remains insufficiently characterised. This study aimed to investigate the impact of sera from patients with arterial hypertension and elevated uric acid levels on the senescence of human umbilical vein endothelial cells, and to determine whether allopurinol treatment modulates this effect.

Materials: Human umbilical vein endothelial cells were cultured and exposed to sera from hypertensive patients with elevated uric acid levels (≥5 mg/dL) before and after six weeks of allopurinol treatment (300 mg/day). A control group consisting of healthy individuals with normal uric acid levels was established. Eighteen participants of both sexes were recruited to the study. Markers of senescence (SA-β-Gal, γ-H2A.X, 53BP1), oxidative stress (mitochondrial and cytosolic reactive oxygen species, mitochondrial mass, membrane potential), cell proliferation and inflammatory cytokine production were analysed.

Results: Sera from hypertensive patients before treatment induced endothelial senescence and oxidative stress and altered secretory profiles in endothelial cells compared to controls; however, allopurinol treatment led to a partial reversal of these changes, including reduced mitochondrial reactive oxygen species, mitochondrial mass and γ-H2A.X levels, and increased cell proliferation. Not all markers returned to baseline, and some inflammatory mediators remained elevated or increased after treatment.

Conclusion: Allopurinol partially reverses uric acid- and hypertension-related endothelial senescence and oxidative damage, but incomplete normalisation suggests multiple overlapping pathways contribute to vascular cell senescence in this context.

The knee joint is a weight-bearing structure that endures varied mechanical stresses in daily and athletic activities. Its cells convert these stresses into biochemical signals through mechanotransduction, prompting changes essential for joint health, repair, and adaptation. Understanding these processes is pivotal for developing rehabilitation strategies that address injuries and degenerative conditions like osteoarthritis. Different loading modalities-compression, tension, shear, and hydrostatic pressure-impact knee tissues (cartilage, synovium, ligaments, and tendons) and their resident cells (chondrocytes, synoviocytes, and fibroblasts). Chondrocytes adjust extracellular matrix synthesis to maintain cartilage integrity, while synoviocytes regulate synovial fluid components crucial for lubrication. Fibroblasts modulate collagen production, preserving ligament and tendon strength. Underlying these activities are key signaling pathways (e.g., MAPK, NF-κB, and Wnt) that regulate gene expression and cellular metabolism in response to mechanical stimuli. By linking basic mechanobiology insights to clinical practice, clinicians can tailor therapeutic interventions-such as controlled loading, exercise regimens, manual therapy, and orthotic devices-to optimize tissue repair, restore function, and prevent further degeneration. This mechanotransduction-focused approach offers a comprehensive framework for improving knee joint health and enhancing rehabilitation outcomes.

Background/aims: Casein influences coagulation, yield, and product quality. This study aimed to develop and validate a papain (EC 3.4.22.2)-based biosensor to quantify casein in whole milk, evaluating its kinetic behavior and comparing it with HPLC.

Methods: Papain was immobilized on nylon membranes and a cassava starch biopolymer. Enzyme kinetics (KM), stability, sensitivity, precision, and linearity of the system were evaluated. A t-test (α = 0.05) was applied to compare the casein concentration obtained by the biosensor versus HPLC (n = 20). Interference from milk proteins and calcium was also analyzed.

Results: The biosensor showed high affinity for casein (KM = 0.037 mM), with a linear range of 0.001-0.03 mM (R² = 0.9974) and a response time <5 s. No significant differences were found with HPLC (p = 0.0665). Stability reached 70 days at 4°C and was reusable up to 15 times.

Conclusion: The developed biosensor proved to be an accurate, fast, and sustainable analytical alternative for the determination of casein in complex milk matrices.

Background/aims: Signal regulatory protein alpha (SIRPα) is an inhibitory receptor expressed on macrophages and dendritic cells. Recent cancer research studies have reported evidence of upregulation of SIRPα on natural killer (NK) cells. The present study aimed to investigate the role of SIRPα in NK cells during viral infection.

Methods: We utilized SIRPα knockout mice (SIRPα-/-) and lymphocytic choriomeningitis virus (LCMV) infection to examine the role of SIRPα in NK cells. Flow cytometry, in vivo killing assays, and molecular analyses were performed to assess NK cell activation, cytotoxic function, and associated signaling pathways.

Results: SIRPα expression was induced on NK cells during LCMV infection. The absence of SIRPα in knockout mice resulted in an increased proportion and activation of NK cells, with enhanced expression of cytotoxic markers and augmented NK cell-mediated killing of target cells. Mechanistically, loss of SIRPα was associated with downregulation of Src homology region 2-containing protein tyrosine phosphatase-1 (SHP-1) in NK cells. Importantly, SIRPα deficiency led to concomitant loss of CD8+ T cells and impaired viral control. In vivo killing assays indicated that activated NK cells mediated CD8+ T cell depletion in SIRPα-/- mice. Experimental NK cell depletion in these mice partially restored T cell immunity, reduced immunopathology, and improved viral clearance.

Conclusion: Our findings identify SIRPα as a critical inhibitory receptor that regulates NK cell effector functions. Loss of SIRPα unleashes NK cell activity but results in CD8+ T cell depletion and impaired antiviral immunity, highlighting the dual role of SIRPα in balancing NK cell activation and adaptive immune responses.

Parasites represent a diverse and widely distributed group of pathogens that cause diseases with significant global health implications. The interaction between parasite and host is characterized by a high degree of complexity, with both parties continuously adapting to changes in the other. The successful host invasion is largely attributable to the evasion strategies employed by parasites to ensure their survival in immunocompetent individuals. In turn, the host's defense mechanisms utilize a variety of structures and processes, ranging from primary barriers to the most sophisticated ones, to counter the parasite attack. Acting as an early line of defense, the immune system includes a variety of cell types that are capable of recognizing, destroying, and eliminating infectious agents. Undoubtedly, the orchestration of first-line innate immune responses but also adaptive immunity processes during infection depends to a large extent on the involvement of tissue-resident mast cells (MCs). MCs are capable of supporting immune reactions to parasites through a broad spectrum of processes, including degranulation, synthesis and release of cytokines/chemokines and other mediators, and the generation of reactive oxygen species (ROS). They may also be involved in immune cell recruitment, phagocytosis, and the provision of extracellular DNA traps. Despite the well documented association of MCs with antibacterial and antiviral defense, their role in host protection against parasites remains incompletely identified. This article provides an overview of the engagement of MCs in host defense mechanisms developed during parasitic infections. Furthermore, it considers the impact of parasites or parasite-derived molecules on the various aspects of MC activity.