Cell-mediated Research Articles

Induction of Ca2+-dependent autophagy and concurrent lysosomal alkalinization underlies the cytotoxic effects of NNC-55-0396 on glioblastoma cells.

Diverse agents targeting (macro)autophagy, a critical metabolic stress response in cancer cells, have been proposed for cancer therapy. In previous studies, we showed that NNC-55-0396 (NNC) induces glioblastoma cell death by activating the Unfolded Protein Response (UPR) of ER stress and increasing cytosolic Ca2+ levels. Here, we report that NNC affects both ends of the autophagy process, causing extensive cytoplasmic vacuolation. Our results show that: (1) NNC induces autophagy downstream of UPR and Ca2+ signaling pathways, thus silencing IRE1α/JNK1 or inhibiting Ca2+/IP3R signaling prevents NNC-induced vacuolation. (2) Silencing ATG5 delays cell death, indicating that autophagy induction plays a role in NNC's cytotoxic effects. (3) NNC and other Ca2+-mobilizing agents transcriptionally upregulate p62/SQSTM1, an autophagosome cargo receptor, highlighting a role for this protein in the response to NNC. (4) Studies using tandem fluorescent-tagged LC3 and electron microscopy, however, further reveal that NNC blocks late-stage autophagy that leads to enlarged degradative compartments accumulating ubiquitin-tagged cargoes. (5) Finally, NNC impedes pro-cathepsin-B processing, an effect that is reversed with a weak acid co-treatment, suggesting that lysosomal dysfunction due to increased intraluminal pH is the underlying cause of the autophagy blockade. Together, these findings underscore a multi-level dysregulation of autophagy that contributes to NNC's anti-tumoral effects.

Comparative in vitro toxicity of compositionally distinct thermal spray particulates in human bronchial cells

Thermal spray, in general, is a process that involves forcing a melted substance, such as metal or ceramic in the form of wire or powder, onto the surface of a targeted object to enhance its desired surface properties. In this paper, the melted substance is metal wire generated by an electric arc and forcibly coated on a rotary iron substrate using compressed air. This thermal process is referred to as double-wire arc thermal spray. The particles generated through these methods fall within the nanometer to micrometer agglomerate size range. There is concern regarding potential human health outcomes as these particles exhibit a similarity in particle morphology to welding fumes. Thermal spray wires with zinc (PMET540), iron and chromium (PMET731), and nickel (PMET885) as primary metal compositions were used to generate particulate via an electric arc wire thermal spray generator for exposure to human bronchial cells (BEAS-2B) to examine comparative toxicity ranging from 0-200µg/mL. Resulting cellular viability was assessed through live cell counts, and percent cytotoxicity was measured as a function of LDH release. Oxidative stress, genotoxicity, and alteration in total antioxidant capacity were evaluated through DNA damage (COMET analysis) and antioxidant concentration at 0, 3.125, 25, and 100µg/mL. Protein markers for endothelin-1 (ET-1), interleukin-6 (IL-6), and interleukin-8 (IL-8) were also assessed to determine inflammation and endothelial alteration. Resultsindicate modulation of oxidative stress response in a material and dose dependent manner. PMET540 exhibited the greatest cytotoxic effect between wires and across doses. DNA damage and antioxidant concentration induced by PMET540 were significantly higher than other wires at higher doses (DNA damage increased at 25 and 100µg/mL; Antioxidant concentration increased at 100µg/mL). However, ET-1 concentration significantly increased only after application of 100µg/mL PMET885. IL-6 and IL-8 were most highly expressed in BEAS2B culture after 25µg/mL exposure to PMET540 (99.4% Zn). This data suggests that metal composition of thermal spray wires dictates the diverse response in human bronchial cells.

Resveratrol Can Differentiate Human Melanoma Stem-like Cells from Spheroids Treated With All-trans Retinoic Acid.

Stem-like cancer cells are believed to be the leading cause of therapy resistance in malignant melanoma (MM). All-trans retinoic acid (ATRA) differentiation therapy is considered a promising approach to eradicate stem-like cancer cells, but some melanoma cells are resistant to ATRA. This study aimed to examine whether resveratrol (RS), a natural polyphenol compound, could improve the response of MM stem-like cells to ATRA and explore the possible underlying mechanisms. MM stem-like cells were established from a spheroid model of A375 human MM cell line. The response to RES alone and in combination with ATRA, was examined through analysis of cancer stemness, cell viability, and protein expression. The stem-like cells showed resistance to the anticancer drug docetaxel; however, the combination of RES and ATRA augmented the effects of docetaxel. Accordingly, these combinatorial effects were associated with significant inhibition of the expression levels of stemness markers CD133, OCT4, CD271, and ABCG2. The tested combinations also led to a significant increase in melanocyte differentiation marker SOX9, while efficiently suppressing the dedifferentiation marker SOX10. Notably, RES alone effectively up-regulated retinoic acid receptor beta (RARβ) expression and down-regulated crucial mediators like DNMT1, polycomb-group proteins EZH2, and BMI-1, which mechanistically explain how RES enhanced the differentiation-inducing effects of ATRA. The resistance of MM stem-like cells to ATRA can be attenuated by RES and combined applications of ATRA and RES provide a promising strategy for MM treatment.

CHUP1 restricts chloroplast movement and effector-triggered immunity in epidermal cells.

Chloroplast Unusual Positioning 1 (CHUP1) plays an important role in the chloroplast avoidance and accumulation responses in mesophyll cells. In epidermal cells, prior research showed silencing CHUP1-induced chloroplast stromules and amplified effector-triggered immunity (ETI); however, the underlying mechanisms remain largely unknown. CHUP1 has a dual function in anchoring chloroplasts and recruiting chloroplast-associated actin (cp-actin) filaments for blue light-induced movement. To determine which function is critical for ETI, we developed an approach to quantify chloroplast anchoring and movement in epidermal cells. Our data show that silencing NbCHUP1 in Nicotiana benthamiana plants increased epidermal chloroplast de-anchoring and basal movement but did not fully disrupt blue light-induced chloroplast movement. Silencing NbCHUP1 auto-activated epidermal chloroplast defense (ECD) responses including stromule formation, perinuclear chloroplast clustering, the epidermal chloroplast response (ECR), and the chloroplast reactive oxygen species (ROS), hydrogen peroxide (H2O2). These findings show chloroplast anchoring restricts a multifaceted ECD response. Our results also show that the accumulated chloroplastic H2O2 in NbCHUP1-silenced plants was not required for the increased basal epidermal chloroplast movement but was essential for increased stromules and enhanced ETI. This finding indicates that chloroplast de-anchoring and H2O2 play separate but essential roles during ETI.

Atopic dermatitis: pathogenesis and therapeutic intervention.

The skin serves as the first protective barrier fornonspecific immunity and encompassesa vast network of skin-associated immune cells. Atopic dermatitis (AD) is a prevalent inflammatory skin disease that affects individuals of all ages and races, with a complex pathogenesis intricately linked to genetic, environmental factors, skin barrier dysfunction as well as immune dysfunction. Individuals diagnosed with AD frequently exhibit genetic predispositions, characterized by mutations that impactthe structural integrity of the skin barrier. This barrier dysfunction leads to the release of alarmins, activating the type 2 immune pathway and recruiting various immune cells to the skin, where they coordinate cutaneous immune responses. In this review, we summarize experimental models of AD and provide an overview of its pathogenesis and the therapeutic interventions. We focus on elucidating the intricate interplay between the immune system of the skin and the complex regulatory mechanisms, as well as commonly used treatments for AD, aiming to systematically understand the cellular and molecular crosstalk in AD-affected skin. Our overarching objective is to provide novel insights and inform potential clinical interventions to reduce the incidence and impact of AD.

Multi-omic characteristics of longitudinal immune profiling after breakthrough infections caused by Omicron BA.5 sublineages

Omicron sub-variants breakthrough infections (BTIs) have led to millions of coronavirus disease 2019 (COVID-19) cases worldwide. The acute-phase immune status is critical for prognosis, however, the dynamic immune profiling of COVID-19 during the first month after BTIs remains unclear. In this study, we monitored the immune dynamics at various timepoints in a longitudinal cohort during the first month post-BTIs through clinical evaluation, single-cell RNA sequencing (scRNA-seq), T cell receptor (TCR)/B cell receptor (BCR) sequencing, and antibody mass spectrometry. Serological analysis revealed limited impairment to functions of major organs, active cellular and humoral immunity at 2 weeks post-BTI, with significant increases in cytokines (CKs) and neutralizing antibody levels. However, 1 month post-BTI, organ function parameters and CK levels reverted to pre-infection levels, whereas neutralizing antibody levels remained high. Notably, scRNA-seq showed that lymphocytes maintained strong antiviral activity and cell depletion at 2 weeks and 1 month post-BTI, with genes CD81, ABHD17A, CXCR4, DUSP1, etc. upregulated, and genes PFDN5, DYNLRB1, CD52, etc. downregulated, indicating that lymphocytes status take longer to recover to normal levels than that routine blood tests revealed. Additionally, T cell-exhaustion associated genes, including LAG3, TIGIT, PDCD1, CTLA4, HAVCR2, and TOX, were upregulated after BTI. TCRs and BCRs exhibited higher clonotypes, mainly in CD8Tem or plasmablast cells, at 2 weeks post-BTI comparing 1 month. More IgG and IgA-type BCRs were found in the groups of 1 month post-BTI, with higher somatic hypermutation, indicating greater maturity. Verification of monoclonal antibodies corresponding to amplified BCRs highlighted the antigen-specific and broad-spectrum characteristics. Our study elucidated the dynamic immune profiling of individuals after Omicron BA.5 sublineages BTI. Strong immune activation, antiviral response, antibody maturation and class transition at 2 weeks and 1 month after BTI may provide essential insights into pathogenicity, sequential immune status, recovery mechanisms of Omicron sublineage BTI. This study was supported by the National Key R&D Program of China, the China Postdoctoral Science Foundation, Guangdong Basic and Applied Basic Research Foundation, the National Natural Science Foundation of China, CAS Project for Young Scientists in Basic Research, and the Air Force Special Medical Center Science and Technology Booster Program.

Strain and hyaluronic acid interact to regulate ovarian cancer cell proliferation, migration, and drug resistance

The ovarian tumor microenvironment plays a critical yet is poorly understood role in the regulation of cancer cell behaviors including proliferation, migration, and response to chemotherapy treatments. Ovarian cancer is the deadliest gynecological cancer, due to diagnosis at late stages of the disease and increased resistance to chemotherapies for recurrent disease. Understanding how the tumor microenvironment (TME) interacts with biomechanical forces to drive changes to ovarian cancer cell behaviors could elucidate novel treatment strategies for this patient population. Additionally, limitations in current preclinical models of the ovarian TME do not permit investigation of crosstalk between signaling pathways and mechanical forces. Our study focused on uncovering how strains and hyaluronic acid (HA) interact to signal through the CD44 receptor to alter ovarian cancer cell growth, migration, and response to a commonly used chemotherapy, paclitaxel. Using an advanced 3D in vitro model, we were able to identify how interactions of strain and HA as in the TME synergistically drive enhanced proliferation and migration in an ovarian tumor model line, while decreasing response to paclitaxel treatment. This study demonstrates the importance of elucidating how the mechanical forces present in the ovarian TME drive disease progression and response to treatment.

Immune checkpoint inhibition and CAR T-cells: no longer exhausted?

Immune checkpoint inhibition and CAR T-cells: no longer exhausted?

Role of chemokines in aging and age-related diseases

Chemokines (chemotactic cytokines) play essential roles in developmental process, immune cell trafficking, inflammation, immunity, angiogenesis, cellular homeostasis, aging, and tumorigenesis. Chemokines also modulate response to immunotherapy, and consequently influence the therapeutic outcome. The mechanisms underlying these processes are accomplished by interaction of chemokines with their cognate cell surface G protein-coupled receptors (GPCRs) and subsequent cellular signaling pathways. Chemokines play crucial role in influencing aging process and age-related diseases across various tissues and organs, primarialy through inflammatory responses (inflammaging), recruitment of macrophages, and orchestrated trafficking of other immune cells. Chemokines are categorized in four distinct groups based on the position and number of the N-terminal cysteine residues; namely, the CC, CXC, CX3C, and (X)C. They mediate inflammatory responses, and thereby considerably impact aging process across multiple organ-systems. Therefore, understanding the underlying mechanisms mediated by chemokines may be of crucial importance in delaying and/or modulating the aging process and preventing age-related diseases. In this review, we highlight recent progress accomplished in understanding the role of chemokines and their cellular signaling pathways involved in aging and age-relaed diseases of various organs. Moreover, we explore potential therapeutic strategies involving chemokines and chemokine receptor antagonists aimed at reducing aging and mitigating age-related diseases. One of the modern methods in this direction involves use of chemokine receptor antagonists and anti-chemokines, which suppress the pro-inflammatory response, thereby helping in resolution of inflammation. Considering the wide-spectrum of functional involvements of chemokines in aging and associated diseases, several clinical trials are being conducted to develop therapeutic approaches using chemokine receptor antagonists to improve life span and promote healthy aging.

Papillomaviruses and Papillomaviral Disease in Dogs and Cats: A Comprehensive Review

Papillomaviruses (PVs) frequently infect humans as well as non-human species. While most PV infections are asymptomatic, PVs can also cause hyperplastic papillomas (warts) as well as pre-neoplastic and neoplastic lesions. In this review, the life cycle of PVs is discussed, along with the mechanisms by which PVs cause hyperplastic and neoplastic diseases. The humoral and cell-mediated immune responses to PVs are reviewed, giving context to the later discussion on the use of vaccines to reduce canine and feline PV-associated disease. Both dogs and cats are infected by numerous different PV types classified into multiple different PV genera. The taxonomic classification of PVs is reviewed, along with the significance of this classification. The PV-associated diseases of dogs and cats are then described. These descriptions include the clinical presentation of the disease, the causative PV types, the histological features that allow diagnosis, and, where appropriate, possible treatment options. The review is comprehensive and contains the latest information about PVs and the diseases they cause in dogs and cats.

Optimum blue light exposure: a means to increase cell-specific productivity in Chinese hamster ovary cells

Research for biopharmaceutical production processes with mammalian cells steadily aims to enhance the cell-specific productivity as a means for optimizing total productivities of bioreactors. Whereas current technologies such as pH, temperature, and osmolality shift require modifications of the cultivation medium, the use of optogenetic switches in recombinant producer cells might be a promising contact-free alternative. However, the proper application of optogenetically engineered cells requires a detailed understanding of basic cellular responses of cells that do not yet contain the optogenetic switches. The knowhow of ideal light exposure to enable the optimum use of related approaches is missing so far. Consequently, the current study set out to find optimum conditions for IgG1 producing Chinese hamster ovary (CHO) cells which were exposed to blue LED light. Growth characteristics, cell-specific productivity using enzyme-linked immunosorbent assay, as well as cell cycle distribution using flow cytometry were analyzed. Whereas too harsh light exposure causes detrimental growth effects that could be compensated with antioxidants, a surprising boost of cell-specific productivity by 57% occurred at optimum high light doses. The increase coincided with an increased number of cells in the G1 phase of the cell cycle after 72 h of illumination. The results present a promising new approach to boost biopharmaceutical productivity of mammalian cells simply by proper light exposure without any further optogenetic engineering.Key points• Blue LED light hinders growth in CHO DP-12 cells• Antioxidants protect to a certain degree from blue light effects• Illumination with blue LED light raises cell-specific productivity

Mitophagy and its regulatory mechanisms in the biological effects of nanomaterials.

Mitophagy is a selective cellular process critical for the removal of damaged mitochondria. It is essential in regulating mitochondrial number, ensuring mitochondrial functionality, and maintaining cellular equilibrium, ultimately influencing cell destiny. Numerous pathologies, such as neurodegenerative diseases, cardiovascular disorders, cancers, and various other conditions, are associated with mitochondrial dysfunctions. Thus, a detailed exploration of the regulatory mechanisms of mitophagy is pivotal for enhancing our understanding and for the discovery of novel preventive and therapeutic options for these diseases. Nanomaterials have become integral in biomedicine and various other sectors, offering advanced solutions for medical uses including biological imaging, drug delivery, and disease diagnostics and therapy. Mitophagy is vital in managing the cellular effects elicited by nanomaterials. This review provides a comprehensive analysis of the molecular mechanisms underpinning mitophagy, underscoring its significant influence on the biological responses of cells to nanomaterials. Nanoparticles can initiate mitophagy via various pathways, among which the PINK1-Parkin pathway is critical for cellular defense against nanomaterial-induced damage by promoting mitophagy. The role of mitophagy in biological effects was induced by nanomaterials, which are associated with alterations in Ca2+ levels, the production of reactive oxygen species, endoplasmic reticulum stress, and lysosomal damage.

The Mastocytosis Control Test: A Patient-Reported Outcome Measure Assessing Disease Control

BACKGROUNDMastocytosis is characterized by expanding neoplastic mast cells in organs such as the skin, bone marrow, and gastrointestinal tract. The release of mast cell mediators triggers cutaneous, gastrointestinal, and other symptoms. Currently, no validated mastocytosis-specific patient-reported outcome measure (PROM) exists to assess disease control. OBJECTIVEHere, we developed a disease-specific instrument, the Mastocytosis Control Test (MCT), for evaluating and monitoring disease control in patients with non-advanced disease. METHODSSix potential MCT items were generated using a combined approach consisting of a literature review, patient interviews, and expert input. Item selection and reduction were performed by impact analysis and inter-item correlation, followed by expert reviews and cognitive debriefings. In a validation study, the resulting MCT was tested for validity and reliability by assessing internal consistency, test-retest reliability, convergent validity, known-groups validity, and receiver operating characteristics (ROC) analysis. RESULTSTen patients participated in the item generation phase and 101 in the item reduction and validation phase. The final MCT consisted of five items. Our methods showed a valid total score, high internal consistency, and test-retest reliability. Convergent and known-groups validity demonstrated a strong correlation with related anchors. The ROC curve analysis suggested a cutoff value of ≥13 points to identify patients with good disease control. CONCLUSIONSThe MCT is a disease-specific, valid, and reliable PROM for adult patients with non-advanced disease. It may measure and monitor disease control in routine daily practice and clinical trials.

Exploring potentials of Electuaries for Controlling Chronic Respiratory Diseases in Unani Medicine: A Systematic Review

Background: Chronic respiratory diseases rate has been increasing alarmingly, causing huge burden on the mortality and morbidity. Environmental pollution and occupational exposure, the major identified risk factors and endless adverse effects of conventional medicine put forward the need for better alternative options. Electuaries are the pharmaceutical formulation of poly herbal drugs that are employed as effective remedy for respiratory disorders in Unani system of medicine. Objective: The aim is to assess the effectiveness of Unani pharmaco-therapeutics in the management of various respiratory diseases and the computation of drug/water and drug/sugar ratio for the elaborated electuaries. Methods: A web-based review on certain selected Unani drugs and its molecular mechanism was carried out using the data bases such as Pub Med, Google Scholar, Science Direct and Scopus published until the end of June 2022. Results: It was observed that several single drugs such as Khayarshambar (Cassia fistula L.), Sapistan (Cordia dichotama Forst), Asl-us- Soos (Glycyrrhiza glabra L.), Khatmi (Althea officianialis L.), Za’fran (Crocus sativus L.), Behīdāna (Cydonia oblonga Mill.) etc. used in Unani formulations claimed to be effective in management of respiratory diseases like COVID 19. The herbs and its chemical constituents showed the preventive effect on respiratory diseases with inflammatory cell mediators, lung pathologies, airway response and immunomodulatory effects. The results of research studies (preclinical, clinical or in silico) and their molecular mechanisms on Electuaries have proved to be optimal for the respiratory system. Conclusion: Unani poly-pharmaceutics showed anti-inflammatory, anti-viral, anti-bacterial, anti-allergic, anti- tussive, mucolytic actions arresting respiratory diseases.

Causal Relationships Between Gut Microbiota, Immune Cell and Pancreatic Cancer: A Two-Step, Two-Sample Mendelian Randomization Study.

Gut microbiota (GM) is associated with both the occurrence and development of pancreatic cancer (PC), and immune cells potentially play a role in this process. This study sought to evaluate the causative effect of GM on PC and to ascertain possible immune cell mediators. The study primarily employed a two-step, two-sample Mendelian randomization (MR) analysis to explore the causal relationship between GM and PC within the European population, placing particular emphasis on the application of the inverse variance weighted (IVW) approach. Additionally, mediation analysis was conducted to explore the potential influence of immune cells as mediators. The MR analysis revealed a significant association between Geminocystis and the risk of PC. Increased abundance of Geminocystis was positively associated with the risk of PC (odds ratio (OR): 2.580, 95% confidence interval (CI): 1.050 - 6.342). The validity of the outcomes was also verified by the sensitivity analysis. The mediation MR analysis showed that the B-cell absolute count served as a partial intermediary in the causal link between Geminocystis and the risk of PC, contributing to 15.321% of the mediating impact. This MR study demonstrated that Geminocystis has a causal relationship with PC and potentially mediates B-cell absolute count in the TBNK panel.

PARylation of HMGA1 desensitizes esophageal squamous cell carcinoma to olaparib.

As a chromatin remodelling factor, high mobility group A1 (HMGA1) plays various roles in both physiological and pathological conditions. However, its role in DNA damage response and DNA damage-based chemotherapy remains largely unexplored. In this study, we report the poly ADP-ribosylation (PARylation) of HMGA1 during DNA damage, leading to desensitization of esophageal squamous cell carcinoma (ESCC) cells to the poly(ADP-ribose) polymerase 1 (PARP1) inhibitor, olaparib. We found that HMGA1 accumulates at sites of DNA damage, where it interacts with PARP1 and undergoes PARylation at residues E47 and E50 in its conserved AT-hook domain. This modification enhances the accumulation of Ku70/Ku80 at the site of DNA damage and activates the DNA-dependent protein kinase catalytic subunit, facilitating nonhomologous end-joining repair. In both subcutaneous tumour models and genetically engineered mouse models of in situ esophageal cancer, HMGA1 interference increased tumour sensitivity to olaparib. Moreover, HMGA1 was highly expressed in ESCC tissues and positively correlated with PARP1 levels as well as poor prognosis in ESCC patients. Taken together, these findings reveal a mechanistic link between HMGA1 and PARP1 in regulating cell responses to DNA damage and suggest that targeting HMGA1 could be a promising strategy to increase cancer cell sensitivity to olaparib.

Cepharanthine inhibits the proliferation of glioblastoma cells by blocking the autophagy–lysosomal pathway

Cepharanthine (CEP) is a Stephania cepharantha-derived bioactive alkaloid that can inhibit the progression of numerous tumors. However, the effects and specific mechanisms of CEP performance in glioblastoma (GBM) remain unclear. Thus, this study focused on exploring the effects of CEP on GBM and clarifying the underlying mechanisms. U251 and U87 cells were selected to estimate the anti-GBM effects of CEP, and the possible targets of CEP were analyzed using RNA sequencing (RNA-seq). Validation experiments based on RNA-seq data were performed to clarify the key pathway by which CEP mediates GBM cells response. Results showed that CEP administration successfully inhibited the proliferation and induced the cell cycle arrest and apoptosis of the GBM cells. RNA-seq analysis after CEP administration identified 386 differentially expressed genes, which were highly enriched in the autophagy–lysosomal pathway. Subsequent findings demonstrated that CEP exhibited the potential to curb GBM progression by causing lysosomal and autophagic dysfunction. Taken together, our results indicate that CEP is a potential drug candidate for GBM intervention.

Impact of repetitive, ultra-short soft X-ray pulses from processing of steel with ultrafast lasers on human cell cultures

Ultrafast lasers, with pulse durations below a few picoseconds, are of significant interest to the industry, offering a cutting-edge approach to enhancing manufacturing processes and enabling the fabrication of intricate components with unparalleled accuracy. When processing metals at irradiances exceeding the evaporation threshold of about 1010 W/cm² these processes can generate ultra-short, soft X-ray pulses with photon energies above 5 keV. This has prompted extensive discussions and regulatory measures on radiation safety. However, the impact of these ultra-short X-ray pulses on molecular pathways in the context of living cells, has not been investigated so far. This paper presents the first molecular characterization of epithelial cell responses to ultra-short soft X-ray pulses, generated during processing of steel with an ultrafast laser. The laser provided pulses of 6.7 ps with a pulse repetition rate of 300 kHz and an average power of 500 W. The irradiance was 1.95 ×1013 W/cm2. Ambient exposure of vitro human cell cultures, followed by imaging of the DNA damage response and fitting of the data to a calibrated model for the absorbed dose, revealed a linear increase in the DNA damage response relative to the exposure dose. This is in line with findings from work using continuous wave soft X-ray sources and suggests that the ultra-short X-ray pulses do not generate additional hazard. This research contributes valuable insights into the biological effects of ultrafast laser processes and their potential implications for user safety.

Cytoskeletal activation of NHE1 regulates mechanosensitive cell volume adaptation and proliferation

Mammalian cells rapidly respond to environmental changes by altering transmembrane water and ion fluxes, changing cell volume. Contractile forces generated by actomyosin have been proposed to mechanically regulate cell volume. However, our findings reveal a different mechanism in adherent cells, where elevated actomyosin activity increases cell volume in normal-like cells (NIH 3T3 and others) through interaction with the sodium-hydrogen exchanger isoform 1 (NHE1). This leads to a slow secondary volume increase (SVI) following the initial regulatory volume decrease during hypotonic shock. The active cell response is further confirmed by intracellular alkalinization during mechanical stretch. Moreover, cytoskeletal activation of NHE1 during SVI deforms the nucleus, causing immediate transcriptomic changes and ERK-dependent growth inhibition. Notably, SVI and its associated changes are absent in many cancer cell lines or cells on compliant substrates with reduced actomyosin activity. Thus, actomyosin acts as a sensory element rather than a force generator during adaptation to environmental challenges.

Bioretention cell response to the combined stresses of rubber particles and heavy metals: Nitrogen removal performance and microbial community characteristics

Bioretention cell response to the combined stresses of rubber particles and heavy metals: Nitrogen removal performance and microbial community characteristics