Endoplasmic reticulum-mitochondrial calcium transport contributes to soft extracellular matrix-triggered mitochondrial dynamics and mitophagy in breast carcinoma cells

Mechanotransductive stabilization of HIF-1α is inhibited by mitochondrial antioxidant therapy in the setting of pulmonary overcirculation

In patients with congenital heart disease, the development of pulmonary arterial hypertension (PAH) is based on vascular exposure to abnormal hemodynamic forces. In our work using a large animal model of increased pulmonary blood flow and pressure, we have previously described a pattern of alterations to vascular cell metabolism, mitochondrial function, and mitochondrial redox signaling, paralleling changes in advanced pulmonary vasculopathy states. Based on our findings and emerging literature, we believe that endothelial mitochondria play a central role in integrating and relaying pathologic mechanotransductive signals in abnormal pulmonary hemodynamics. In this manuscript, we demonstrate that exposure of the pulmonary vascular endothelium to aberrant mechanical forces increases production of mitochondrial reactive oxygen species (ROS) and stabilizes the transcription factor Hypoxia Inducible Factor-1α (HIF-1α), and that these changes are associated with impaired endothelial production of Nitric Oxide (NO). We validate that the mitochondrial antioxidant 10-(6'-ubiquinonyl)decyltriphenylphosphonium bromide (MitoQ) can reverse these alterations in vitro, and evaluate the effects of MitoQ treatment in vivo utilizing our large animal shunt model. We find that MitoQ therapy in pulmonary overcirculation decreases the production of mitochondrial ROS, diminishes the mechanically-induced stabilization of HIF-1α, and partially restores vascular reactivity by rescuing endothelial NO production. These findings raise exciting prospects concerning shared pathophysiologic mechanisms and possible common therapeutic targets amongst PAH etiologies.

Dual Role of CRABP2 in Colorectal Cancer: Oncogenesis via Nuclear RB1 and Cytoplasmic AFG3L2/SLC25A39 Axis, While Limiting Liver Metastasis through Cytoplasmic AFG3L2/PINK1/Parkin-Mediated Mitophagy

Colorectal cancer (CRC) progression and metastasis involve numerous regulatory factors. Among these, cellular retinoic acid-binding protein 2 (CRABP2) has been implicated as both a tumor activator and suppressor. Here, it is aimed to clarify the role of CRABP2 in CRC growth and metastasis and explore the underlying molecular mechanisms mediating its cellular functions. Using both in vitro and in vivo models, including a colonocyte-specific CRABP2 conditional knockout mouse model (Crabp2ΔIEC) and a subcutaneous tumorigenesis assay in BALB/c nude mice, it is shown that nuclear CRABP2 enhances tumor growth by interacting with and downregulating the tumor suppressor RB1, whereas cytoplasmic CRABP2 suppresses CRC liver metastasis by interacting with AFG3L2 and promoting mitophagy. In addition, the AFG3L2-SLC25A39 axis is identified as a distinct mechanism by which cytoplasmic CRABP2 increases mitochondrial glutathione stability to promote cell proliferation independent of the nuclear RB1 pathway. Notably, analysis of tissue from CRC patients reveals that CRABP2 protein has distinct prognostic implications and functional roles in the progression and metastasis of CRC dependent on its subcellular localization. Ultimately, by elucidating the role of CRABP2 in CRC, it is aimed to provide new insight into disease pathogenesis and inform the development of therapeutic interventions.

Integrative research on the mechanisms of acupuncture mechanics and interdisciplinary innovation

As a traditional therapeutic approach, acupuncture benefits from modern biomechanics, which offers a unique perspective for understanding its mechanisms by investigating the mechanical properties of biological tissues and cells under force, deformation, and movement. This review summarizes recent advancements in the biomechanics of acupuncture, focusing on three main areas: the mechanical effects of acupuncture, the transmission mechanisms of mechanical signals, and the personalization and precision of acupuncture treatments. First, the review introduces the structural basis of the tissues involved in acupuncture; analyzes the mechanical responses of the skin, dermis, and subcutaneous tissues from needle insertion to point activation; and discusses how these responses impact acupuncture efficacy. Second, the phenomenon of mechanical coupling during acupuncture is discussed in detail, especially the role of connective tissues, including the wrapping and self-locking of collagen fibers, the remodeling of the cytoskeleton and the regulation of mitochondrial function triggered by acupuncture. Third, this article examines the mechanisms of mechanical signal transmission in acupuncture, explaining how mechanosensitive ion channels are activated during the procedure and subsequently initiate a cascade of biochemical responses. Finally, the review highlights the numerical simulation methods used in acupuncture, including the mechanical modeling of skin tissues, the exploration of the mechanical mechanisms of acupuncture, and visualization studies of the needling process. By integrating multidisciplinary research findings, this paper delves into the entire mechanical process of acupuncture, from skin penetration to point stimulation, and analyzes tissue responses to provide a solid theoretical foundation for the scientific study of acupuncture. In addition, directions for future research to further refine acupuncture techniques for clinical applications are proposed.

Review on the role of autophagy in the toxicity of nanoparticles and the signaling pathways involved

As the development of nanotechnology, the application of nanoproducts and the advancement of nanomedicine, the contact of nanoparticles (NPs) with human body is becoming increasingly prevalent. This escalation elevates the risk of NPs exposure for workers, consumers, researchers, and both aquatic and terrestrial organisms throughout the production, usage, and disposal stages. Consequently, evaluating nanotoxicity remains critically important, though standardized assessment criteria are still lacking. The diverse and complex properties of NPs further complicate the understanding of their toxicological mechanisms. Autophagy, a fundamental cellular process, exhibits dual functions-both pro-survival and pro-death. This review offers an updated perspective on the dual roles of autophagy in nanotoxicity and examines the factors influencing autophagic responses. However, no definitive framework exists for predicting NPs-induced autophagy. Beyond the conventional autophagy pathways, the review highlights specific transcription factors activated by NPs and explores metabolic reprogramming. Particular attention is given to NPs-induced selective autophagy, including mitophagy, ER-phagy, ferritinophagy, lysophagy, and lipophagy. Additionally, the review investigates autophagy's involvement in NPs-mediated biological processes such as ferroptosis, inflammation, macrophage polarization, epithelial-mesenchymal transition, tumor cell proliferation and drug resistance, as well as liver and kidney injury, neurotoxicity, and other diseases. In summary, this review presents a novel update on selective autophagy-mediated nanotoxicity and elucidates the broader interactions of autophagy in NPs-induced biological processes. Collectively, these insights offer valuable strategies for mitigating nanotoxicity through autophagy modulation and advancing the development of NPs in biomedical applications.

A review of the pathogenesis of mitochondria in breast cancer and progress of targeting mitochondria for breast cancer treatment

With breast cancer being the most common tumor among women in the world today, it is also the leading cause of cancer-related deaths. Standard treatments include chemotherapy, surgery, endocrine therapy, and targeted therapy. However, the heterogeneity, drug resistance, and poor prognosis of breast cancer highlight an urgent need for further exploration of its underlying mechanisms. Mitochondria, highly dynamic intracellular organelles, play a pivotal role in maintaining cellular energy metabolism. Altered mitochondrial function plays a critical role in various diseases, and recent studies have elucidated its pathophysiological mechanisms in breast carcinogenesis. This review explores the role of mitochondrial dysfunction in breast cancer pathogenesis and assesses potential mitochondria-targeted therapies.

Current insights on mitochondria-associated endoplasmic reticulum membranes (MAMs) and their significance in the pathophysiology of ocular disorders

The intricate interaction network necessary for essential physiological functions underscores the interdependence among eukaryotic cells. Mitochondria-Associated Endoplasmic Reticulum Membranes (MAMs), specialized junctions between mitochondria and the ER, were recently discovered. These junctions participate in various cellular processes, including calcium level regulation, lipid metabolism, mitochondrial integrity maintenance, autophagy, and inflammatory responses via modulating the structure and molecular composition of various cellular components. Therefore, MAMs contribute to the pathophysiology of numerous ocular disorders, including Diabetic Retinopathy (DR), Age-related Macular Degeneration (AMD) and glaucoma. In addition to providing a concise overview of the architectural and functional aspects of MAMs, this review explores the key pathogenetic pathways involving MAMs in the development of several ocular disorders.

Soft extracellular matrix drives endoplasmic reticulum stress-dependent S quiescence underlying molecular traits of pulmonary basal cells

Cell culture on soft matrix, either in 2D and 3D, preserves the characteristics of progenitors. However, the mechanism by which the mechanical microenvironment determines progenitor phenotype, and its relevance to human biology, remains poorly described. Here we designed multi-well hydrogel plates with a high degree of physico-chemical uniformity to reliably address the molecular mechanism underlying cell state modification driven by physiological stiffness. Cell cycle, differentiation and metabolic activity could be studied in parallel assays, showing that the soft environment promotes an atypical S-phase quiescence and prevents cell drift, while preserving the differentiation capacities of human bronchoepithelial cells. These softness-sensitive responses are associated with calcium leakage from the endoplasmic reticulum (ER) and defects in proteostasis and enhanced basal ER stress. The analysis of available single cell data of the human lung also showed that this non-conventional state coming from the soft extracellular environment is indeed consistent with molecular feature of pulmonary basal cells. Overall, this study demonstrates that mechanical mimicry in 2D culture supports allows to maintain progenitor cells in a state of high physiological relevance for characterizing the molecular events that govern progenitor biology in human tissues. STATEMENT OF SIGNIFICANCE: This study focuses on the molecular mechanism behind the progenitor state induced by a soft environment. Using innovative hydrogel supports mimicking normal human lung stiffness, the data presented demonstrate that lung mechanics prevent drift while preserving the differentiation capabilities of lung epithelial cells. Furthermore, we show that the cells are positioned in a quiescent state in the atypical S phase. Mechanistically, we demonstrate that this quiescence: i) is driven by calcium leakage from the endoplasmic reticulum (ER) and basal activation of the PERK branch of ER stress signalling, and ii) protects cells from lethal ER stress caused by metabolic stress. Finally, we validate using human single-cell data that these molecular features identified on the soft matrix are found in basal lung cells. Our results reveal original and relevant molecular mechanisms orchestrating cell fate in a soft environment and resistance to exogenous stresses, thus providing new fundamental and clinical insights into basal cell biology.

ROS-mediated NRF2/p-ERK1/2 signaling-involved mitophagy contributes to macrophages activation induced by CdTe quantum dots

Cadmium telluride (CdTe) quantum dots (QDs) have garnered significant attention for tumor imaging due to their exceptional properties. However, there remains a need for further investigation into their potential toxicity mechanisms and corresponding enhancements. Herein, CdTe QDs were observed to accumulate in mouse liver, leading to a remarkable overproduction of IL-1β and IL-6. Additionally, there was evidence of macrophage infiltration and activation following exposure to 12.5 μmol/kg body weight of QDs. To elucidate the underlying mechanism of macrophage activation, CdTe QDs functionalized with 3-mercaptopropionic acid (MPA) were utilized. In vitro experiments revealed that 1.0 μM MPA-CdTe QDs activated PINK1-dependent mitophagy in RAW264.7 macrophages. Critically, the autophagic flux remained unimpeded, as demonstrated by the absence of p62 accumulation, LC3 turnover assay results, and successful fusion of autophagosomes with lysosomes. Mechanically, QDs increased reactive oxygen species (ROS) and mitoROS by damaging both mitochondria and lysosomes. ROS, in turn, inhibited NRF2, resulting in the phosphorylation of ERK1/2 and subsequent activation of mitophagy. Notably, 1.0 μM QDs disrupted lysosomes but autophagic flux was not impaired. Eventually, the involvement of the ROS-NRF2-ERK1/2 pathway-mediated mitophagy in the increase of IL-1β and IL-6 in macrophages was confirmed using Trolox, MitoTEMPO, ML385, specific siRNAs, and lentivirus-based interventions. This study innovatively revealed the pro-inflammatory rather than anti-inflammatory role of mitophagy in nanotoxicology, shedding new light on the mechanisms of mitochondrial disorders induced by QDs and identifying several molecular targets to comprehend the toxicological mechanisms of CdTe QDs.

Matrix stiffness affects tumor-associated macrophage functional polarization and its potential in tumor therapy

The extracellular matrix (ECM) plays critical roles in cytoskeletal support, biomechanical transduction and biochemical signal transformation. Tumor-associated macrophage (TAM) function is regulated by matrix stiffness in solid tumors and is often associated with poor prognosis. ECM stiffness-induced mechanical cues can activate cell membrane mechanoreceptors and corresponding mechanotransducers in the cytoplasm, modulating the phenotype of TAMs. Currently, tuning TAM polarization through matrix stiffness-induced mechanical stimulation has received increasing attention, whereas its effect on TAM fate has rarely been summarized. A better understanding of the relationship between matrix stiffness and macrophage function will contribute to the development of new strategies for cancer therapy. In this review, we first introduced the overall relationship between macrophage polarization and matrix stiffness, analyzed the changes in mechanoreceptors and mechanotransducers mediated by matrix stiffness on macrophage function and tumor progression, and finally summarized the effects of targeting ECM stiffness on tumor prognosis to provide insight into this new field.