Experimental Cell Research

Autophagy contributes to normal cells physiology and is essential for progression of malignant tumors. While autophagy is mostly considered as a self-degradative and self-renewal process, it has non-degradative functions whose contribution to tumor progression is poorly explored. Here we use the autophagy dependent Drosophila RasV12, Scrib-/- carcinoma model to examine whether perturbation of distinct steps of autophagy differentially influences tumor progression. We found that inhibition of autophagosome formation, by mutating Atg13 or Atg6 either in the tumor or in the whole animal significantly decreased tumor growth. In contrast, blocking the later autophagosome-lysosome fusion (by loss of Vps39 or Syx17) and thereby autolysosomal degradation, does not reduce tumor size. We observed that an early (Atg13), but not a late (Vps39 or Syx17) block in autophagy showed reduced activity of JAK/STAT signaling, known to be critical for the progression of this tumor type. Importantly, we demonstrated that both Atg13 and Vps39 deficient tumors accumulated Stat92E inhibitor Su(var)2-10/dPIAS, a recently identified autophagic cargo, however in Vps39 mutants Su(var)2-10 is sequestered into autophagosomes. Finally, we found that reduction of Su(var)2-10 partially restores JAK/STAT signaling and rescues the growth of Atg13-deficient tumors, indicating its sequestration is a crucial mechanism to promote tumor progression.

Mechanosensing involves proteins detecting mechanical changes in the cytoskeleton or at cell adhesion sites. These interactions initiate signaling cascades that produce biochemical effects such as post-translational modifications or cytoskeletal rearrangements. Filamin is a ubiquitous mechanosensing protein that binds actin filaments and senses pulling forces within the cytoskeleton. Drosophila Filamin (Cheerio) is structurally similar to mammalian Filamin, with roles in egg chamber development, embryo cellularization, and integrity of muscle attachment sites and Z discs in Drosophila indirect flight muscles (IFMs). Here we report a potential novel binding partner of Drosophila Filamins: the death-associated protein kinase Drak that functions as a myosin light chain kinase. We found that Drak biochemically bound to an open mutant of Filamin that resembles the mechanically activated form partially bound to wild type Filamin and did not bind to closed mutant of Filamin. The interaction site was mapped to the intrinsically unfolded C-terminal region of Drak. To study the functional role of Drak-Filamin interaction, we studied two developmental events where Drak has been earlier shown to be expressed and where Filamin also functions: early embryonic cellularization and indirect flight muscle development at pupal stages. We found partial colocalization between Drak-GFP and Filamin-mCherry during the initiation of cellularization furrow, and at the time of myotube attachment site maturation in tendon cells. However, functionally we could not show direct correlation between Filamin and Drak. Our studies reveal interesting new expression patterns of Drak during Drosophila development and provide detailed information about Filamin localization during IFM development.

Mesenchymal stem cells (MSCs) have garnered significant attention over the past three decades due to their robust regenerative potential, primarily mediated by their paracrine activity by releasing soluble bioactive factors and extracellular vesicles (EVs). The MSC secretome plays a pivotal role in wound healing by influencing cellular migration, inflammation, angiogenesis, extracellular matrix (ECM) remodeling, and re-epithelialization. SPARC (Secreted Protein Acidic and Rich in Cysteine), a multifunctional ECM glycoprotein involved in tissue repair and remodeling, regulates key processes such as cell migration, proliferation, angiogenesis, and survival. Despite its known role in ECM dynamics, the impact of SPARC expression on the regenerative properties of MSCs remains underexplored. In this study, we hypothesized that SPARC overexpression in MSCs enhances their secretomes regenerative capacity. Using lentiviral systems, we generated SPARC-overexpressing (+SPARC) and SPARC-knockdown (KD-SPARC) MSCs to investigate SPARCs role in wound healing. Conditioned media (CM) derived from these MSCs were analyzed in vitro for their effects on human skin keratinocytes and fibroblasts. Our results revealed that SPARC expression significantly influences cell-specific migration and cell cycle. Furthermore, in an in vivo wound healing model, CM from +SPARC MSCs accelerated regeneration, while SPARC absence in MSCs CM delayed the healing process. These findings underscore the critical role of SPARC in modulating MSC secretome composition and enhancing its regenerative efficacy. This study highlights SPARC as a promising therapeutic target for the development of advanced regenerative therapies aimed at improving cutaneous wound healing outcomes.

Unlike mammals and birds, where new muscle fiber formation (hyperplasia) ceases around birth, large and fast-growing fish such as rainbow trout undergo a spectacular post-hatching surge of hyperplasia, followed by a considerably delayed hyperplasia decline. This study investigated the roles of the satellite cells (SCs) and their niche in this decline by determining the number and the myogenic capacity of the muscle progenitors as well as the functionality of their direct tissue environment. Histological analysis revealed a significant decrease in hyperplasia (fibers <25 {micro}m) and SC numbers (Pax7+) between 10 g and 500 g trout. Transplantation experiments using muscle-derived cells (MDCs) from mlc2-GFP transgenic trout (10 g to 2 kg donors into 10 g to 2 kg recipients) demonstrated a marked decline in both intrinsic myogenic capacity and niche functionality as trout grow from 10 g to 500 g. Detailed analyses of GFP+ fibers produced after transplantation showed an enrichment of small-diameter GFP+ fibers in 10 g but not 100 g trout recipient muscles, showing a rapid impairment in niche ability to support hyperplasia. In addition, transplantation of MDCs from trout of different ages but the same weight, showed that increasing trout weight, but not aging, is associated with an impairment of the myogenic capacity of progenitors and their niche. Overall, these findings show that the muscle hyperplasia decline in trout is primarily driven by early impairment of the SC niche, followed by a reduction in their myogenic capacity and number, with weight gain playing a more critical role than aging.

Mesenchymal stem cells (MSCs) cultured in hypoxic conditions have been suggested to have more therapeutic efficacy than those cultured under normoxic conditions, and there is growing interest in using hypoxic MSCs for clinical treatment, particularly human umbilical cord (hUC)-MSCs. We investigated how hUC-MSCs and human bone marrow (hBM)-MSCs change from normoxia to hypoxia (1% O2) for 2 weeks of culture. In the growth speed and population doubling time, hUC-MSCs cultured under hypoxia exhibited a significantly higher proliferation rate beyond cancerous cells, such as human glioblastoma and breast cancer cells, while hBM-MSCs did not show a significant difference between normoxia and hypoxia, and were statistically slower than these cancerous cells. Notably, hypoxic hUC-MSCs showed upregulation of genes related to metabolic reprogramming (cholesterol biosynthesis and fatty acid metabolism pathways) and cancer stem cell-like phenotype (factors related to Wnt and Hedgehog signaling pathways, cell proliferation drivers, and apoptosis-resistance), and lesser migration and homing to the traumatic brain injury than normoxic hUC-MSCs after intravenous injection. Thus, whether hUC-MSCs cultured under hypoxia offer clinical benefits and use are safe, given their extremely accelerated proliferation rate and partial cancer stem cell-like traits, requires comprehensive and careful investigation.

Mammalian spermatogenesis occurs in the seminiferous tubules, which exhibit unique spatiotemporal differentiation patterns known as cellular association patterns. In mice, these patterns can be regarded as one-dimensional wavetrains that consistently propagate inward from both ends, resulting in one or more "sites of reversal." Segmented wavetrain pattern, in which the wave propagation direction spatially switches, was observed in our previous three-species reaction-diffusion model for interspecific species difference in spermatogenic waves (Kawamura et al., 2021). However, the biological mechanisms of the formation of sites of reversal and of this directional bias, as well as the principle of pattern formation, remain unknown. Here, we refined our previous model to match the actual biological spatiotemporal scale and examined its dynamics through extensive numerical simulations. The modified model frequently generated segmented wavetrain patterns, corresponding to the sites of reversal, but without directional bias. We systematically examined possible biological mechanisms for the bias and found that tubule elongation, especially near the rete testis, most effectively accounts for the bias among the tested. Extensive simulations revealed that the segmented pattern is numerically stable, emerges more frequently in longer domains, and shows an exponential segment size distribution with a lower limit for the stably existing segment length. These explorations imply that locally emerged unidirectional wavetrains serve as building blocks to generate the stable segmented wavetrains through their interactions. HighlightsO_LISegmented wavetrains reflect sites of reversal in seminiferous tubules. C_LIO_LISegmented patterns frequently emerge but show no inherent directional bias. C_LIO_LITubule elongation may contribute to inward propagation near the rete testis. C_LIO_LISegmented wavetrains are numerically stable and more frequent in longer domains. C_LIO_LIInteractions of local unidirectional wavetrains generate stable segmented structures. C_LI

BackgroundApproximately one-third of men having undergone gonadotoxic treatment in their childhood experience impaired testicular function for whom autologous transplantation of cryopreserved immature testicular tissue may represent the only opportunity to restore their fertility. Pre-clinical studies have demonstrated successful restoration of spermatogenesis following grafting of immature testicular tissue in various species, including non-human primates. In 2002, our institution pioneered with clinical testicular tissue banking for fertility preservation in boys and adolescents. Over time, this strategy has been increasingly implemented by numerous fertility centres worldwide for patients at high risk of treatment-induced sterility. Here, we report the first human case of autologous transplantation of frozen-thawed immature testicular tissue. PatientIn 2008, testicular tissue was cryopreserved from a pre-pubertal boy diagnosed with sickle cell disease. The procedure was performed after a three-year hydroxyurea treatment and prior to receiving conditioning therapy with busulfan and cyclophosphamide for haematopoietic stem cell transplantation. One testis was surgically removed, sectioned into small fragments, and cryopreserved. Histological analysis confirmed preserved tubular architecture and the presence of spermatogonia. During the period from 2022 to 2024, the patient consistently presented with azoospermia. In December 2024, at the time of transplantation, two abnormal sperm cells were detected after enzymatic digestion. MethodEleven testicular tissue fragments (4-21 mm3) were thawed and autologously grafted to four intra-testicular and four subcutaneous scrotal sites. Over a one-year follow-up period, graft survival, vascularization, hormone profiles, and semen parameters were monitored. One year after transplantation, all grafts were surgically retrieved. ResultsPost-operative recovery was uneventful. No significant changes in endocrine or semen parameters were observed during follow-up. Whereas the intra-testicular grafts exhibited a compact parenchyma that was distinct from the looser surrounding adult parenchyma and remained readily identifiable as graft tissue, the scrotal grafts appeared more fibrotic. Enzymatic digestion of the grafts was required to recover spermatozoa, with one spermatozoon obtained from one of the four intra-testicular grafts. Histological evaluation revealed intact tubular architecture and maturation of somatic cells across all grafts. Spermatogonial stem cells, together with evidence of active spermatogenesis, were identified in two of the four intra-testicular grafts, whereas no germ cells were detected in the subcutaneous scrotal grafts. ConclusionThese findings demonstrate that human immature testicular tissue can survive long-term cryostorage, revascularize after transplantation and establish spermatogenesis in vivo. This study provides essential proof-of-concept for fertility restoration in individuals who banked testicular tissue before puberty. FundingThis study was supported by the Research Programme of FWO Vlaanderen (Research Foundation-Flanders; G0A6U25N) and VUB strategic research program (SRP89). Trial Registration: NCT05414045

Following our laboratorys earlier observations on systemic damage inflicted by sev-Gal4 driven activated Ras (sev>RasV12) over-expression in Drosophila larval eye discs, we now show that sev>RasV12 expressing males suffer enhanced eye roughening and pupal death than female sibs because the former have significantly greater Ras levels in ommatidial cells than in female counterpart. In normally developing ommatidial cells, TBPH/TDP-43 was more abundant in cytoplasm in male than in female eye discs. The sev>RasV12 expression reduced nuclear TBPH in female eye discs but caused no apparent change in males. Caz/Fus, an interacting partner of TBPH, was significantly downregulated in sev>RasV12 eye discs, more so in males. Significant reduction in the microtubule binding protein Futsch in eye discs of sev>RasV12 larvae of either sexes but female-specific elevation of Fas2 appears to be due to the above normal developmental differences in TBPH and Caz in female and male ommatidial cells and because Sxl, the master regulator of sex-determination, is present only in females. In view of known auto-regulatory loop between Fas2 and Ras, we suggest that elevated levels of Fas2 cause levels of Ras to be much less elevated in sev>RasV12 female eye discs than in male sibs. This results in greater local and systemic damage in males. These findings have general and clinical relevance since perturbed Ras signaling is a major factor in several diseases, including cancer.

Epidermal Growth factor (EGF) signaling is associated with (oncogenic) proliferation. Conversely, EGF-family ligands are able to trigger a differentiation program in cultured cells, an effect attributed to ligand affinity and EGFR phosphorylation. How EGF/EGFR driven proliferation-differentiation dynamics underlie tissue self-renewal has not been addressed. We show that culturing mouse small intestinal organoids (mSIOs) without EGF enhanced EGFR expression and base phosphorylation while maintaining a balanced development of proliferative crypts and differentiated villi. Addition of EGF or EREG triggers receptor endocytosis, reducing cell-surface and expression levels. While EGF promoted crypt proliferation, EREG promoted both proliferation and villus differentiation compared to untreated controls. Removal or re-introduction of EGF or EREG proved sufficient to induce development comparable to constant presence of ligands over 96h. Sub-saturating concentrations of EGF led to increased villus differentiation, resembling EREG treatments, suggesting that control over EGFR endocytic cycle ultimately regulates the balance of proliferation and differentiation in mSIOs SummaryExpression and signaling competency at the plasma membrane of EGFR drives crypt proliferation vs villus differentiation by medium ligand-composition, aiding mouse intestinal organoids self-renewal and regeneration.

Progenitor cells in aged tissues undergo changes in their microenvironment that may impact their functionality during regeneration. Despite recent advances in understanding the role of adult lung progenitors, the impact of aging on these cells remains unclear. To analyze aging modifications, we used aged wild-type mice of 18-24 months old, and Zmpste24-/- deficient mice, which exhibit an accelerated aging phenotype. A three-dimensional organoid culture system was employed to assess the lung regeneration capacity. Additionally, mouse epithelial cells and fibroblasts were isolated and characterized with senescence and autophagy markers. Our findings revealed that lung epithelial cells from aged mice and Zmpste24-/- mice hold their regeneration capacity, maintaining their phenotype and a healthy cellular state through an increase in autophagy, particularly when co-cultured with healthy fibroblasts. Conversely, cultured fibroblasts from Zmpste24-/- mice show nuclear defects and acquire a senescent phenotype, characterized by mTORC1 activation and reduced autophagy, which in turn impairs organoid formation. Moreover, these progenitor cells become increasingly susceptible to mechanical stress with aging due to reduced nuclear lamins and the Zmpste24 defect. This vulnerability is illustrated by FACS sorting, which can further compromise their regenerative potential. Our results indicate that, in aging, progenitor cells and their fibroblast niche integrate microenvironmental signals that shape cell-cell interactions essential for lung regeneration.

Astroglia can counteract the harmful effects of -synuclein (-SYN) protofibrils and reverse premature cellular senescence by promoting tunneling nanotubes (TNTs). However, the mechanism behind this recovery is unknown. This study is the first to examine TNT-mediated mechanical stability in senescent astroglial recovery. We demonstrate that disruption of Lamin A/C in -SYN-protofibrils-treated senescent cells reduces actin-cytoskeleton stress, as measured by nucleus flatness index and isometric scale factor from quantitative microscopy. ROCK (Rho-associated kinase) inhibition, which is crucial for reducing actin-cytoskeleton tension, promotes TNTs. Small molecules like Cytochalasin-D, Nocodazole, and Jasplakinolide, which inhibit TNTs by altering actin tension other than ROCK pathway, cannot reverse senescence. RNA-sequence heatmaps reveal changes in senescence-, integrin-, and ROCK-pathway genes; STRING links these to the Hippo pathway. Experimental results show that cytosolic YAP translocation, a key regulator of Hippo pathway, is vital for TNT formation and actin-based stability in U87-MG astrocytoma and primary astrocytes. Interestingly, TNTs form between two cells with different actin tensions: one exhibits low actin tension with Hippo signaling on, while the other has higher actin tension with Hippo signaling off. The most notable observation is the high abundance of YAP inside the TNTs, along with actin. The study shows that TNTs maintain mechanical stability through Lamin A/C integrity and actin tension in -SYN-induced senescent astroglia, thereby protecting the cells, reversing senescence. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=163 SRC="FIGDIR/small/711517v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@192307dorg.highwire.dtl.DTLVardef@ad8b75org.highwire.dtl.DTLVardef@19ece78org.highwire.dtl.DTLVardef@1056395_HPS_FORMAT_FIGEXP M_FIG C_FIG

The association between higher levels of physical activity and lower cancer risk and mortality is well established. However, a causal link is yet to be proven. Recent studies showed a decrease in the proliferation rates of cultured human cancer cells when the human serum employed to stimulate them was conditioned by acute exercise. Here, we tested the hypothesis that serum mediates some of the putative benefits of exercise on cancer through alterations to the growth pattern and susceptibility to chemotherapy agents of cancer cells. To this end, human non-small cell lung cancer (NSCLC) cells were exposed to serum from two cohorts that differed significantly on their levels of physical activity and, accordingly, cardiorespiratory fitness, but were otherwise identical (master athletes and non-exercisers), collected before and after an acute exercise intervention. Serum levels of glucose, lipids, albumin, C-reactive protein and cytokines were determined and the impact of the serum responses to acute and lifelong exercise on the above-mentioned parameters were analyzed. We found that acute exercise decreased the cells proliferation rate, yet shortened the cells lag phase after detachment, whereas lifelong exercise had the opposite effects. Significantly, we showed, for the first time, that lifelong exercise increased susceptibility to a chemotherapy agent (cisplatin), which may contribute to the decreased cancer mortality rates found among those who exercise regularly. Similar to the cellular effects, changes to serum cytokine levels - several of them linked to the senescence-associated secretory phenotype - depended on whether serum was conditioned by acute or by chronic exercise. Key pointsChronic exercise increased the in vitro susceptibility of lung cancer cells to cisplatin. Acute and chronic exercise modulated the in vitro tumorigenic potential of lung cancer cells. Effects were mediated by serological changes produced by exercise. Acute and chronic exercise had distinct impacts on serological cytokine levels.

Sugar-induced cell death (SICD) remains an intriguing but poorly studied phenomenon in the physiology of Saccharomyces cerevisiae. Recently, it was shown that SICD development largely depends on the redirection of glucose fluxes between glycolysis and the pentose phosphate pathway (PPP). In particular, inhibition of glycolysis by iodoacetamide (IAA) was observed to reduce SICD levels. This study is devoted to further investigation of the relationship between SICD and the functionality of the two PPP branches. It was shown that deletion of the ZWF1 gene does not affect the decrease in SICD levels in IAA-treated cells. This allows us to conclude that the oxidative branch of the PPP is not involved in the suppression of SICD/ROS. Deletion of the GLR1 gene and attenuation of the TRR1 gene also did not restore SICD levels in cells after IAA treatment. The obtained results indicate that the level of reduced glutathione or thioredoxin does not affect SICD genesis. The addition of 5 mM ribose-5-phosphate (R5P) to the incubation medium led to suppression of SICD by 79%. At the same time, the addition of 5 mM ribose + 5 mM Pi suppressed SICD by only 20%. Suppression of SICD by 5 mM R5P in the{Delta} pho3 strain (83%) excludes the mechanism of extracellular dephosphorylation of R5P to ribose, its subsequent transport into the cell, and re-phosphorylation inside the cell. Furthermore, more than 70% suppression of SICD in the{Delta} end3 strain with 5 mM R5P excludes endocytosis as a mechanism of R5P import into the cell. The observed effect of R5P can be explained by the moonlighting function of some unknown protein. Thus, SICD development in S. cerevisiae cells depends on the final product of the non-oxidative PPP--R5P.

This retrospective study aims to explore the interactive effects of biological maturation and relative age effect (RAE) on talent identification. 56 male elite soccer players matched for chronological age (15.08{+/-}0.41 years) were studied. Test items included anthropometry (height, body mass, sitting height, leg length, BMI and Quetelet index), physiology (power, speed, agility, speed endurance and aerobic performance), soccer-specific skills (passing, shooting and dribbling), psychology (achievement motivation, orientation and resilience) and biological maturation (APHV) tests. The test results were analyzed independent sample t-test, Pearson correlation analysis, and stratified regression. Conclusion: Biological maturation significantly influences anthropometry (height, weight and Quetelet index), lower limb explosive, and speed (single-leg jump, standing triple jump, and 30-m sprint) in U16 male elite soccer players in Shanghai. The relative age effect shows no significant impact on talent selection indicators, which is attributed to the accumulated training load effect. The mechanisms of biological maturation and RAE in youth soccer talent selection are distinct and operate independently.

The ryanodine receptor (RYR) genes encode evolutionarily conserved calcium release channels involved in a wide range of calcium-dependent biological processes. Here we show that the sole Drosophila RYR gene (dRyR) functions in differentiated somatic and cardiac muscle as well as in developing embryonic myotubes. In the larval body wall muscles, dRyR protein localizes at the SR membranes and dRyR knockdown adversely affects muscle contractility, suggesting its conserved role in calcium-triggered E-C coupling. After dRyR attenuation, sarcomere and mitochondrial patterns are severely impaired, showing dRyR involvement in structural muscle properties. However, dRyR is also prominently expressed and functionally required in growing embryonic muscles. dRyR loss of function leads to myotube growth defects and thin myofiber phenotypes, while its overexpression induces myofiber splitting. Given the structural and functional conservation of dRyR, we used Drosophila to test the impact of one human RYR1 variant of unknown significance (VUS). Larvae carrying p.Met4881Ile RYR1 VUS showed impaired mobility and altered structural muscle properties reminiscent of those seen in dRyR knockdown, thus indicating it is likely pathogenic. Overall, we show that Drosophila dRyR plays a conserved role in setting muscle contractility and structural muscle features. Our findings underline the still under-investigated role of dRyR as a promyogenic factor and provide a first example of the impact assessment of a human RYR1 VUS in Drosophila.

Chemotaxis plays a critical role in the metastatic progression of breast cancer. The chemokine CXCL12 is well recognized as an essential component of chemotactic migration in triple-negative breast cancer (TNBC) cells in vivo. The purpose of this study is to determine how the highly metastatic TNBC cell line, MDA-MB-231, migrates in response to well-defined CXCL12 gradients in vitro. Traditional 2D transwell migration assays were optimized to gauge the MDA-MB-231 cells responsiveness to various CXCL12 concentrations. The optimum chemoattractant concentrations were applied to a commercially available 3D chemotaxis assay as stable linearly diffused gradients. Cells were embedded in type 1 bovine collagen at two different collagen concentrations, and individual unlabeled cells were monitored for 24 hours using brightfield microscopy. Time-lapse videos were used to track cell movement and shape. Quantitative data analysis was performed using an automated tracking software to measure chemotactic parameters based on cell morphology. MDA-MB-231 cells were responsive to CXCL12 concentrations greater than 200 ng/mL in 2D and 3D systems. In 3D systems, significant directed migration was observed in denser collagen matrices. It was observed that in 3D matrices a range of cell morphologies was present. Therefore, chemotaxis was evaluated as a function of cell shape revealing some differences between sub cellular populations. Our findings show the cells shape influences the chemotactic sensing towards CXCL12 gradients.

Intervertebral disc degeneration is characterized by inflammation, extracellular matrix breakdown, and neurovascular ingrowth, processes that contribute to discogenic, chronic back pain. The transient receptor potential canonical 6 (TRPC6) channel is a calcium-permeable ion channel implicated in inflammation and pain signaling in multiple tissues; however, its functional role in human disc cells remain unknown. Here, we investigated the expression, activation, and downstream consequences of TRPC6 activation using Hyp9, a pharmacological activator of TRPC6. TRPC6 transcripts were consistently detected across all donors examined (n = 17). Functional TRPC6 activation induced a rapid, dose-dependent calcium (Ca2+) influx across 0.5-100 {micro}M Hyp9. TRPC6 activation did not reduce metabolic activity or increase cytotoxicity at concentrations commonly used for in vitro TRPC6 activation. Mechanistically, TRPC6 activation induced mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-{kappa}B) pathways, as demonstrated by increased phosphorylation of p38 and extracellular signal-regulated kinase (ERK), degradation of the inhibitor of {kappa}B-alpha (I{kappa}B-), and increased nuclear translocation of the NF-{kappa}B p65 subunit. Downstream of these early signaling events, TRPC6 activation elicited a robust inflammatory and catabolic response with upregulation of IL-6, IL-8, COX-2, MMP-1, MMP-3, NGF, and VEGF, with corresponding increases in protein secretion. These findings identify TRPC6 as an important signaling node linking calcium influx to inflammatory, catabolic, and neuro- and angiogenesis-associated pathways in disc cells, highlighting TRPC6 as a potential therapeutic target in degenerative disc disease. HighlightsO_ST_ABSWhat are the main findings?C_ST_ABSO_LITRPC6 is endogenously expressed in human intervertebral disc cells, and its activation induces rapid calcium influx that initiates MAPK and NF-{kappa}B signaling pathways. C_LIO_LITRPC6 activation initiates a broad inflammatory and degenerative program, elevating the expression of IL-6, IL-8, COX-2, MMP-1, MMP-3, NGF, and VEGF. C_LI What are the implications of the main findings?O_LITRPC6 functions as a key upstream regulator linking calcium influx with inflammatory, matrix-degrading, and neuro-angiogenic processes central to disc degeneration and discogenic back pain. C_LIO_LIPharmacological targeting of TRPC6 may offer a novel therapeutic approach to suppress early inflammatory signaling, limit extracellular matrix breakdown, and reduce neurovascular ingrowth in degenerative disc disease. C_LI

Intervertebral disc degeneration is associated with loss of nucleus pulposus (NP) cell phenotype and extracellular matrix, both processes linked to changes in cytoskeletal contractility and cell shape. Here, we tested whether microenvironment-specific modulation of RhoA signaling can restore NP-like morphology and gene expression in NP cells cultured in 2D and in 3D alginate. In 2D monolayer culture, where cells are spread and mechanically activated, pharmacologic inhibition of RhoA with CT04 reduced RhoA activity, decreased actomyosin contractility gene expression, and shifted morphology toward a smaller, more circular phenotype. Bulk RNA sequencing showed that CT04 treatment increased expression of NP phenotypic and matrix-related genes including ACAN, GDF5, CHST3, and MUSTN1 while decreasing expression of catabolic and fibroblast-associated genes including ADAMTS1/9 and COL1, consistent with enrichment of extracellular matrix pathways. In contrast, RhoA activation with CN03 in 2D culture increased actin and phosphorylated myosin light chain intensity but produced limited phenotypic improvement. In 3D alginate, which minimizes integrin-mediated adhesion, baseline actomyosin markers were reduced relative to 2D culture. In alginate, RhoA activation with CN03 increased the amount of actin, phosphorylated myosin light chain, and actomyosin gene expression, yet also promoted a more compact, circular morphology and increased NP markers, including ACAN and KRT19 with repeated dosing. Across culture conditions, increased cell roundness was consistently associated with increased ACAN expression, indicating strong coupling between cytoskeletal state, morphology, and NP matrix programs. Together, these findings demonstrate that RhoA pathway perturbation can promote NP phenotypic gene expression in both 2D and 3D culture, but the direction of optimal modulation depends on the microenvironment, supporting RhoA signaling as a context-dependent therapeutic target for disc regeneration.

ObjectiveDiffuse cutaneous systemic sclerosis (dcSSc) is a life-limiting fibrotic disease. We and others have shown that dcSSc fibroblasts accumulate numerous somatic mutations associated with senescence-like features; however, the mechanism(s) enabling their survival remain unclear. MethodsSkin biopsies were obtained from lesional tissues from dcSSc (n=10), dcSSc treated with autologous hematopoietic stem cell transplantation (ASCT, n=8) or 7 age/sex-matched healthy controls. Primary dermal fibroblasts were generated from biopsies. Spatial RNA sequencing, immunoblotting, confocal microscopy, and functional assays were used to mechanistically delineate signaling pathways linking DNA-damage with fibroblast survival. ResultsdcSSc fibroblasts demonstrated increased pH2AX DNA double-strand-break foci yet remained apoptosis resistant. These cells displayed features of metabolic-stress remodeling, including mitochondrial hyperpolarization, increased reactive oxygen species production, and enhanced mitochondrial biogenesis. Spatial transcriptomics and subsequent biochemical analyses identified activation of a PERK/ATF4/FOXO1 axis, characterized by PERK phosphorylation, selective ATF4 translation, FOXO1 nuclear translocation, and induction of downstream antioxidant and metabolic programs. In contrast, fibroblasts from post-ASCT patients exhibited normalization of DNA-damage markers and mitochondrial parameters without ATF4/FOXO1 activation. Pharmacologic inhibition of either PERK or FOXO1 selectively restored mitochondrial-dependent apoptosis in dcSSc fibroblasts, demonstrating that this axis is required for their survival following extensive genomic injury. ConclusiondcSSc fibroblasts persist despite substantial genomic injury by engaging a PERK/ATF4/FOXO1 metabolic-adaptation program that suppresses mitochondrial-dependent apoptosis. This survival axis is not present after ASCT. Targeting PERK or FOXO1 restores apoptosis selectively in dcSSc fibroblasts, highlighting its potential use as a therapeutic target for eliminating pathogenic senescence-like fibroblasts in dcSSc. HighlightsO_LIBoth ex-vivo skin and in-vitro primary dermal fibroblasts derived from dcSSc patients have a higher frequency of intrinsic DNA damage signals and senescence-associated features; yet they evade mitochondrial-dependent apoptosis. C_LIO_LIPathogenic dcSSc fibroblasts rewire their metabolism, characterized by mitochondrial hyperpolarization and elevated ROS. C_LIO_LISpatial transcriptomics and functional analyses reveal a PERK/ATF4/FOXO1 stress-adaptation axis that drives fibroblast survival in dcSSc. C_LIO_LIThis maladaptive survival program characterized by increased genotoxic stress, and mitochondrial remodelling is absent in post-ASCT fibroblasts. C_LIO_LITargeting PERK or FOXO1 selectively sensitizes dcSSc fibroblasts to apoptosis revealing a potential promising therapeutic strategy in dcSSc. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/706443v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1b3f791org.highwire.dtl.DTLVardef@42548aorg.highwire.dtl.DTLVardef@bc4ce1org.highwire.dtl.DTLVardef@5b4d48_HPS_FORMAT_FIGEXP M_FIG C_FIG

Cultured meat technology, with its significant advantages of shortening meat production cycles, reducing natural resource consumption, minimizing the risk of zoonotic disease transmission, and enabling precise control over nutritional composition and texture, offers a novel alternative source for human meat consumption. One of the major challenges to produce cultured meat in large scale is how to establish high.quality seed cells, which should have long term proliferative capacities and are able to differentiate into muscles efficienuy with simple procedures. Here, we first established an engineered porcine expanded potential stem cells (Tet-On-PAX7 EPSCs) containing Tet-On regulated PAX7 gene. Then the Tet-On-PAX7 EPSCs were induced to somite-liKe mesodermal cells. These somite-liKe mesodermal cells can be expanded over 1025-fold even after 40 passages in-vitro culture while retaining strong myogenic potential. The somite-like mesodermal cells treated with DOX for one day would differentiate into muscle stem cells (Muses), and the later were able to differentiate into muscles with an efficiency of up to 90% within just 7 days in 11-FSDeDa without Dox. Moreover, when somite-liKe mesodermal cells were seeded on patterned scaffolds, microcarrier scaffolds, or cultured in anchorage-independent suspension, they maintained high efficiency in muscle differentiation, confirming their potential to be used as seed cells for scaled cultured meat production.