YAP/TAZ upstream signals and downstream responses

SQLE amplification accelerates esophageal squamous cell carcinoma tumorigenesis and metastasis through oncometabolite 2,3-oxidosqualene repressing Hippo pathway

Esophageal squamous cell carcinoma (ESCC) is one of the most prevalent cancers worldwide, characterized by a dismal prognosis and elusive therapeutic targets. Dysregulated cholesterol metabolism is a critical hallmark of cancer cells, facilitating tumor progression. Here, we used whole genome sequencing data from several ESCC cohorts to identify the important role of squalene epoxidase (SQLE) in promoting ESCC tumorigenesis and metastasis. Specifically, our findings highlight the significance of 2,3-oxidosqualene, an intermediate metabolite of cholesterol biosynthesis, synthesized by SQLE and metabolized by lanosterol synthase (LSS), as a key regulator of ESCC progression. Mechanistically, the interaction between 2,3-oxidosqualene and vinculin enhances the nuclear accumulation of Yes-associated protein 1 (YAP), thereby increasing YAP/TEAD-dependent gene expression and accelerating both tumor growth and metastasis. In a 4-nitroquinoline 1-oxide (4-NQO)-induced ESCC mouse model, overexpression of Sqle resulted in accelerated tumorigenesis compared to wild-type controls, highlighting the pivotal role of SQLE in vivo. Furthermore, elevated SQLE expression in ESCC patients correlates with a poorer prognoses, suggesting potential therapeutic avenues for treatment. In conclusion, our study elucidates the oncogenic function of 2,3-oxidosqualene as a naturally occurring metabolite and proposes modulation of its levels as a promising therapeutic strategy for ESCC.

A YAP-derived peptide blocks YAP-TEAD signaling and suppresses cell proliferation

Yes-associated protein (YAP), a pivotal transcriptional co-activator in cell growth regulation, exerts its function through interactions with transcriptional factors like TEAD. Ectopic activation of YAP causes excessive cell proliferation, leading to multiple human diseases, including cancers. However, current pharmacological YAP inhibition lacks specificity and may have unintended effects, necessitating the development of direct YAP-derived inhibitors. In this study, we designed a novel YAP-derived peptide, TBDi, that specifically disrupted YAP-TEAD interaction and exhibited robust inhibition of TEAD activity. Mechanistically, TBDi directly binds to TEAD, blocking the physical interaction between YAP and TEAD. Transcriptomic analysis revealed that TBDi significantly altered gene expression profiles associated with TEAD activity, including downregulation of signature genes like CYR61 and CTGF. Functionally, TBDi emerged as a potent suppressor of cell proliferation, inhibiting cell proliferation to a degree comparable to YAP/TAZ knockdown. Altogether, our study not only identifies TBDi as a promising tool to block YAP-TEAD axis, but also offers insights for potential therapeutic interventions in diseases.

Mechanomemory after short episodes of intermittent stresses induces YAP translocation via increasing F-actin

How forces and mechanics influence and regulate living cells remains elusive. Mechanomemory, the response to a mechanical perturbation that persists after the perturbation is removed, is believed to be a key to understanding the impact of forces and mechanics on cell functions. Recently, our lab has demonstrated the presence of mechanomemory that lasts for ∼30 min after applying external stress via integrins. Herein, we test the hypothesis that applications of short intermittent episodes of stress exert long-term effects on mechanomemory via the process of mechanotransduction. An Arginine-Glycine-Aspartic acid (RGD)-peptides-coated 4-μm magnetic bead was bound to the integrin receptors to apply stresses to the surface of a Chinese Hamster Ovary cell. At the same stress magnitude and frequency (15 Pa at 0.3 Hz), multiple cycles of externally applied intermittent 2 or 10 min stresses with 15 min intervals, 10 min stresses with 10 min intervals, or a 30 min stress plus a 30 min load-free interval increased nuclear translocation of YAP (Yes-Associated Protein) and Ctgf gene expression, like that by a 60 min continuous stress, but a 30 min continuous stress did not. Short durations of intermittent stresses increased F-actin in the cytoplasm, which coincided with the elevated YAP translocation. Inhibiting F-actin or actomyosin but not microtubules blocked stress-induced YAP translocation to the nucleus. Cells on soft substrates translocate more YAP than on stiff substrates after external load release. These results highlight the impact of multiple intermittent stresses-induced cytoplasmic mechanomemory on cell biological functions via YAP translocation.

Advancements of anticancer agents by targeting the Hippo signalling pathway: biological activity, selectivity, docking analysis, and structure-activity relationship

The Hippo signalling pathway is prominent and governs cell proliferation and stem cell activity, acting as a growth regulator and tumour suppressor. Defects in Hippo signalling and hyperactivation of its downstream effector's Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) play roles in cancer development, implying that pharmacological inhibition of YAP and TAZ activity could be an effective cancer treatment strategy. Conversely, YAP and TAZ can also have beneficial effects in promoting tissue repair and regeneration following damage, therefore their activation may be therapeutically effective in certain instances. Recently, a complex network of intracellular and extracellular signalling mechanisms that affect YAP and TAZ activity has been uncovered. The YAP/TAZ-TEAD interaction leads to tumour development and the protein structure of YAP/TAZ-TEAD includes three interfaces and one hydrophobic pocket. There are clinical and preclinical trial drugs available to inhibit the hippo signalling pathway, but these drugs have moderate to severe side effects, so researchers are in search of novel, potent, and selective hippo signalling pathway inhibitors. In this review, we have discussed the hippo pathway in detail, including its structure, activation, and role in cancer. We have also provided the various inhibitors under clinical and preclinical trials, and advancement of small molecules their detailed docking analysis, structure-activity relationship, and biological activity. We anticipate that the current study will be a helpful resource for researchers.

Activation of Hippo/YAP signaling pathway exacerbates vascular remodeling and aggravates hypertension by upregulating Foxm1

The Hippo/YAP signaling pathway is closely related to the occurrence and development of cardiovascular diseases. However, it's still unclear whether this pathway plays a certain role in hypertension. In this study, aortic morphology and function in spontaneously hypertensive rats (SHR) were comprehensively evaluated using Wistar-Kyoto rats (WKY) as controls. Results indicated that the aorta of SHRs have distinct changes in pathological structure. Furthermore, the proliferative activity of vascular smooth muscle cells (VSMCs) was enhanced, with vascular fibrosis being aggravated. Immunohistochemical analysis revealed that SHRs exhibited high expression of Yes-Associated Protein (YAP). Western Blot analysis showed that cytoplasmic YAP and TAZ expression decreased in hypertensive rats, indicating that YAP/TAZ nuclear transfer increased and Hippo/YAP signaling pathway had been activated. The cell function experiments of VSMCs extracted from rat aorta showed that the cell viability and proliferation ability of VSMCs in SHRs were enhanced, the expression of Fibronectin and collagen I was increased, and vascular fibrosis was aggravated. siRNA-YAP (si-YAP) can reverse the above phenomenon in VSMCs. Knockdown of YAP can inhibit Foxm1 expression. As an inhibitor of large tumor suppressor kinases LAST1/2, GA-107 can inhibit the phosphorylation level of YAP, increase blood pressure, aggravate aortic pathomorphological changes, promote VSMCs proliferation and vascular fibrosis, and thus aggravate hypertension symptoms in SHRs. However, these effects of GA-107 can be antagonized by inhibiting Foxm1 with thiosulfathiazole (Thio). Conclusively, Hippo/YAP signaling pathway promotes vascular remodeling through the regulation of Foxm1 and causes hypertension.

Nuclear ubiquitination permits Hippo-YAP signal for liver development and tumorigenesis

Hippo-YAP signaling is crucial to organ development and tumorigenesis. VGLL4, which occupies TEAD to prevent YAP binding, is the main transcriptional repressor of Hippo-YAP activity. Here we identified the nuclear E3 ligase ubiquitin protein ligase E3 component n-recognin 5 (UBR5) poly-ubiquitinated VGLL4 at Lys61 for its degradation, which permits Hippo-YAP signaling for the development of the liver biliary system in mice and multiple cancers in humans. In mouse liver development, Ubr5 and Vgll4 exhibited reciprocal expression patterns spatiotemporally. Ubr5 deletion impaired cholangiocyte development and hepatocyte reprogramming, which could be efficiently rescued by restoring Hippo-YAP through ablating Vgll4. We also found that the UBR5-VGLL4-YAP axis is associated with the progression of human pan-cancers. Targeting nuclear E3 ligases in multiple types of patient-derived tumor organoids suppressed their expansion. Our identification of UBR5 as the bona fide E3 ligase of VGLL4 offers a molecular framework of nuclear Hippo-YAP regulation and suggests nuclear ubiquitination as a potential therapeutic target for YAP-dependent malignancies.

Yes-associated Protein Induces Age-dependent Inflammatory Signaling in the Pulmonary Endothelium

Acute Lung Injury (ALI) causes the highly lethal Acute Respiratory Distress Syndrome (ARDS) in children and adults, for which therapy is lacking. Children with Pediatric ARDS (PARDS) have a mortality rate that is about half of adults with ARDS. Improved ALI measures can be reproduced in rodent models with juvenile animals, suggesting that physiologic differences may underlie these outcomes. Here, we show that pneumonia-induced ALI caused inflammatory signaling in the endothelium of adult mice which depended on Yes-associated protein (YAP). This signaling was not present in 21-day-old weanling mice. Transcriptomic analysis of lung endothelial responses revealed nuclear factor kappa-B (NF-κB) as significantly increased with ALI in adult versus weanling mice. Blockade of YAP signaling protected against inflammatory response, hypoxemia, and NF-κB nuclear translocation in response to Pseudomonas aeruginosa pneumonia in adult mice. Our results demonstrate an important signaling cascade in the lung endothelium of adult mice that is not present in weanlings. We suggest other pathways may also exhibit age-dependent signaling, which would have important implications for ARDS therapeutics in the adult and pediatric age groups.

YAP/TAZ: An Epitome of Tumorigenesis

Mounting evidence has demonstrated that the transcriptional coactivators Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), are the main effectors of the Hippo signal transduction pathway that is involved in multiple layered events in tumorigenesis. The role of YAP/TAZ in cancer development is critical in a context dependent manner. Overexpression of YAP/TAZ induces cell proliferation and is elevated in various cancers and many other malignancies. On the other hand, studies have shown YAP binds p73 to activate PML transcription in response to DNA damage and generate a DNA-damage-induced feedback loop. Intriguingly, at the genomic level, YAP/TAZ genes are rarely mutated in cancer, except in specific tumors. The central role of YAP/TAZ in driving tumorigenesis is attributed through diverse mechanisms, such as regulatory kinases, cellular mechano-transduction, epigenetic modification/alterations, post-translational modifications, protein -protein interaction and nucleo-cytoplasmic export import. The complex interplay among feedback loops and crosstalk between various signaling pathways portrays the dynamic nature of YAP/TAZ. Thus, a comprehensive understanding of how posttranslational modifications and nucleo-cytoplasmic traffic of YAP/TAZ dynamically regulate and control each other holds great promise for selectively targeting YAP/TAZ import and export for drug therapy.

Integration of focal adhesion morphogenesis and polarity by DOCK5 promotes YAP/TAZ-driven drug resistance in TNBC

YAP and TAZ are transcriptional co-activators that are inhibited by sequestration in the cytoplasm. Cellular signalling pathways integrate soluble, mechanical (cytoskeleton, adhesion), and geometric (cell size, morphology) cues to regulate the translocation of YAP/TAZ to the nucleus. In triple-negative breast cancer (TNBC) cells, both signalling and morphogenesis are frequently rewired, leading to increased YAP/TAZ translocation, which drives proliferation, invasion, and drug resistance. However, whether this increased YAP/TAZ translocation is due to alterations in upstream signalling events or changes in cell morphology remains unclear. To gain insight into YAP/TAZ regulation in TNBC cells, we performed multiplexed quantitative genetic screens for YAP/TAZ localisation and cell shape, enabling us to determine whether changes in YAP/TAZ localisation following gene knockdown could be explained by alterations in cell morphology. These screens revealed that the focal adhesion (FA)-associated RhoGEF DOCK5 is essential for YAP/TAZ nuclear localisation in TNBC cells. DOCK5-defective cells exhibit defects in FA morphogenesis and fail to generate a stable, polarised leading edge, which we propose contributes to impaired YAP/TAZ translocation. Mechanistically, we implicate DOCK5's ability to act as a RacGEF and as a scaffold for NCK/AKT as key to its role in FA morphogenesis. Importantly, DOCK5 is essential for promoting the resistance of LM2 cells to the clinically used MEK inhibitor Binimetinib. Taken together, our findings suggest that DOCK5's role in TNBC cell shape determination drives YAP/TAZ upregulation and drug resistance.

Auranofin resensitizes ferroptosis-resistant lung cancer cells to ferroptosis inducers

Lung cancer, a major cause of cancer-related mortality, has limited therapeutic options, especially for advanced cases. Ferroptosis, an iron-dependent form of cell death, is a potential therapeutic strategy for this disease; however, resistance mechanisms in the tumor microenvironment impede its effectiveness. Therefore, in this study, we aimed to investigate the efficacy of sulfasalazine (SAS), a ferroptosis inducer, and auranofin (AUR), a Food and Drug Administration-approved anti-inflammatory agent, combination to counteract ferroptosis resistance in lung cancer. SAS induced ferroptosis in vitro; however, its efficacy in vivo was limited, possibly because of factors, such as nutrient deprivation and high cell density, in the microenvironment that suppressed the activities of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), key regulators of ferroptosis resistance. Screening of 2483 drugs revealed AUR as a compound resensitizing the YAP/TAZ-deficient lung cancer cells to ferroptosis. Moreover, SAS and AUR combination significantly enhanced lipid peroxidation and reactive oxygen species accumulation, further driving ferroptosis in cells. This combination effectively inhibited tumor growth and enhanced survival in a murine lung cancer model. Overall, our findings suggest that AUR potentiates ferroptosis-based therapies, serving as an effective candidate to overcome ferroptosis resistance in lung cancer.

Magnesium Ions Induce Endothelial Cell Differentiation into Tip Cell and Enhance Vascularized Bone Regeneration

Vascularization has been considered an essential strategy for bone regeneration and can be promoted by magnesium ions (Mg2+). During angiogenesis, the differentiation of endothelial cells (ECs) into tip cell is a critical step since it controls the growth direction and pattern of new vascular sprouts. While several studies have noted the pro-angiogenic effects of Mg2+, however, their specific influence on tip cell formation is unclear. Therefore, this research seeks to examine the impact of Mg2+ on tip cells and elucidate the potential mechanisms involved. The results reveal that Mg2+ shows good compatibility and stimulates ECs to migrate and invade in vitro. Moreover, Mg2+ enhances EC spheroids sprouting and elevates the expression of genes linked to tip cells. The underlying mechanisms are that Mg2+ facilitates tip cell differentiation via the VEGFA-VEGFR2/Notch1 signaling pathway crosstalk and promotes migration and filopodia formation of tip cells and proliferation of stalk cells by inducing YAP nuclear translocation, culminating in the maturation of vascular networks. Furthermore, EC spheroids stimulated by Mg2+ load in hydrogel enhance vascularized bone regeneration in vivo. These findings enrich the understanding of how Mg2+ influence blood vessel formation and provide practical strategies for the development and design of magnesium-based biomaterials.

A near death experience: The secret stem cell life of caspase-3

Caspase-3 is known to play a pivotal role in mediating apoptosis, a key programmed cell death pathway. While extensive research has focused on understanding how caspase-3 is activated and functions during apoptosis, emerging evidence has revealed its significant non-apoptotic roles across various cell types, including stem cells. This review explores the critical involvement of caspase-3 in regulating stem cell properties, maintaining stem cell populations, and facilitating tissue regeneration. We also explore the potential pathological consequences of caspase-3 dysfunction in stem cells and cancer cells alongside the therapeutic opportunities of targeting caspase-3.

VGLL2 and TEAD1 fusion proteins identified in human sarcoma drive YAP/TAZ-independent tumorigenesis by engaging EP300

Studies on Hippo pathway regulation of tumorigenesis largely center on YAP and TAZ, the transcriptional co-regulators of TEADs. Here, we present an oncogenic mechanism involving VGLL and TEAD fusions that is Hippo pathway-related but YAP/TAZ-independent. We characterize two recurrent fusions, VGLL2-NCOA2 and TEAD1-NCOA2, recently identified in human spindle cell rhabdomyosarcoma. We demonstrate that in contrast to VGLL2 and TEAD1 the fusion proteins are potent activators of TEAD-dependent transcription, and the function of these fusion proteins does not require YAP/TAZ. Furthermore, we identify that VGLL2 and TEAD1 fusions engage specific epigenetic regulation by recruiting histone acetyltransferase EP300 to control TEAD-mediated transcriptional and epigenetic landscapes. We show that small-molecule EP300 inhibition can suppress fusion protein-induced oncogenic transformation both in vitro and in vivo in mouse models. Overall, our study reveals a molecular basis for VGLL involvement in cancer and provides a framework for targeting tumors carrying VGLL, TEAD, or NCOA translocations.

Effects of PDMS culture on stem cell differentiation towards definitive endoderm and hepatocytes

The generation of human induced pluripotent stem cell (hiPSC) derivatives for regenerative medicine applications holds tremendous promise in treating various disorders. One critical target includes liver disease, in which the primary curative treatment is a cellular transplant aimed to restore the lost function of hepatocytes. In an effort to improve the differentiation of hiPSC-derived liver tissue, we manipulated the mechanical conditions of endoderm specification through directed perturbation of the cytoskeleton and through 2D substrate culture on viscoelastic materials. Through a combination of qRT-PCR, immunofluorescence staining, and functional assays, we found that mechanical cues can bias endoderm specification in an actomyosin and Yes-associated protein (YAP) dependent manner, unveiling new insights into mechanotransduction in germ layer specification and downstream maturation toward parenchymal cells. STATEMENT OF SIGNIFICANCE: The translational potential of using human induced pluripotent stem cell (hiPSC) derived hepatocytes to therapeutically improve impaired liver function holds great clinical promise. However, challenges remain in efficiently differentiating functional hepatocytes with mature marker expression. In an effort to improve the differentiation efficiency of hepatocytes, the role of early mechanosensing mechanisms was investigated in the specification of hiPSCs to definitive endoderm progenitor populations. Through a combination of cytoskeletal modulation, control of mechanoresponsive, yes-associated protein expression, and culture on physiologically compliant PDMS substrates, we found that soft environments not only improve progenitor specification but also impact the downstream functionality of differentiated hepatocytes. These results contribute to the collective appreciation that mechanical cues are critical in developmental processes.

Non-canonical Wnt signaling promotes epithelial fluidization in the repairing airway

Concerted migration of basal stem cells (BCs) in the airway, also known as epithelial fluidization, has been implicated in epithelial repair after injury. How BC migration is regulated, and how it influences the success of epithelial repair, remains unclear. Here we have identified non-canonical Wnt signaling through Ptk7, Fzd7, and YAP as a critical regulator of BC migration in the mouse trachea. Using live imaging and genetic studies in the mouse, we find that Ptk7 is required for the concerted movement of BCs after injury, and that this requirement extends to BC proliferation and subsequent restoration of epithelial homeostasis after injury. We demonstrate that Ptk7 exerts this function in conjunction with Wnt5a and Fzd7, and through YAP activation in BCs. Our data provide mechanistic insight into the regulation of epithelial repair in the airway.

Targeting rapid TKI-induced AXL upregulation overcomes adaptive ERK reactivation and exerts antileukemic effects in FLT3/ITD acute myeloid leukemia

Acute myeloid leukemia (AML) patients with the FMS-related receptor tyrosine kinase 3 internal tandem duplication (FLT3/ITD) mutation have a poorer prognosis, and treatment with FLT3 tyrosine kinase inhibitors (TKIs) has been hindered by resistance mechanisms. One such mechanism is known as adaptive resistance, in which downstream signaling pathways are reactivated after initial inhibition. Past work has shown that FLT3/ITD cells undergo adaptive resistance through the reactivation of extracellular signal-regulated kinase (ERK) signaling within 24 h of sustained FLT3 inhibition. We investigated the mechanism(s) responsible for this ERK reactivation and hypothesized that targeting tyrosine-protein kinase receptor UFO (AXL), another receptor tyrosine kinase that has been implicated in cancer resistance, may overcome the adaptive ERK reactivation. Experiments revealed that AXL is upregulated and activated in FLT3/ITD cell lines mere hours after commencing TKI treatment. AXL inhibition combined with FLT3 inhibition to decrease the ERK signal rebound and to exert greater anti-leukemia effects than with either treatment alone. Finally, we observed that TKI-induced AXL upregulation occurs in patient samples, and combined inhibition of both AXL and FLT3 increased efficacy in our in vivo models. Taken together, these data suggest that AXL plays a role in adaptive resistance in FLT3/ITD AML and that combined AXL and FLT3 inhibition might improve FLT3/ITD AML patient outcomes.

Matrix Stiffness Regulates the Osteogenic Differentiation of hPDLSCs via DNA Methylation

OBJECTIVES

This study aimed to examine the influence of matrix stiffness on osteogenic differentiation via epigenetic mechanisms in human periodontal ligament stem cells (hPDLSCs), with implications for understanding orthodontic tooth movement.

MATERIALS AND METHODS

hPDLSCs were cultured on substrates with varying stiffness (soft and stiff). Dot blot and immunofluorescence techniques were employed to measure global DNA methylation levels. RT-qPCR and alkaline phosphatase (ALP) activity assays were conducted to assess differences in DNA methylation and osteogenic potential. Additionally, ELISA was used to quantify DNA methyltransferase content and activity.

RESULTS

hPDLSCs on stiffer substrates exhibited increased 5-methylcytosine (5-mC) and higher global DNA methylation levels than those on soft substrates. With increased matrix stiffness, DNMT3A and DNMT3B mRNA expression levels rose. hPDLSCs on stiff matrices also showed elevated DNMT3B enzyme content and osteogenic activity. When global DNA methylation was reduced, mRNA levels of RUNX2, ALP, and Col-1 decreased, along with a notable reduction in ALP staining intensity in the inhibitor group.

CONCLUSIONS

Matrix stiffness is positively associated with global DNA methylation, with DNMT3B likely mediating this regulation in hPDLSCs. Furthermore, DNA methylation levels are positively linked to the osteogenic capability of hPDLSCs.

Selective inhibition of stromal mechanosensing suppresses cardiac fibrosis

Matrix-derived biophysical cues are known to regulate the activation of fibroblasts and their subsequent transdifferentiation into myofibroblasts1-6, but whether modulation of these signals can suppress fibrosis in intact tissues remains unclear, particularly in the cardiovascular system7-10. Here we demonstrate across multiple scales that inhibition of matrix mechanosensing in persistently activated cardiac fibroblasts potentiates-in concert with soluble regulators of the TGFβ pathway-a robust transcriptomic, morphological and metabolic shift towards quiescence. By conducting a meta-analysis of public human and mouse single-cell sequencing datasets, we identify the focal-adhesion-associated tyrosine kinase SRC as a fibroblast-enriched mechanosensor that can be targeted selectively in stromal cells to mimic the effects of matrix softening in vivo. Pharmacological inhibition of SRC by saracatinib, coupled with TGFβ suppression, induces synergistic repression of key profibrotic gene programs in fibroblasts, characterized by a marked inhibition of the MRTF-SRF pathway, which is not seen after treatment with either drug alone. Importantly, the dual treatment alleviates contractile dysfunction in fibrotic engineered heart tissues and in a mouse model of heart failure. Our findings point to joint inhibition of SRC-mediated stromal mechanosensing and TGFβ signalling as a potential mechanotherapeutic strategy for treating cardiovascular fibrosis.

Massage-Mimicking Nanosheets Mechanically Reorganize Inter-organelle Contacts to Restore Mitochondrial Functions in Parkinson's Disease

Parkinson's disease (PD) is exacerbated by dysfunction of inter-organelle contact, which depends on cellular responses to the mechanical microenvironment and can be regulated by external mechanical forces. Delivering dynamic mechanical forces to neural cells proves challenging due to the skull. Inspired by the effects of massage; here PEGylated black phosphorus nanosheets (PEG-BPNS), known for their excellent biocompatibility, biodegradability, specific surface area, mechanical strength, and flexibility, are introduced, which are capable of adhering to neural cell membrane and generating mechanical stimulation with their lateral size of 200 nm, exhibiting therapeutic potential in a 1-methyl-4-phenyl-1,2,3,6-te-trahydropyridine-induced PD mouse model by regulating inter-organelle contacts. Specifically, it is found that 200 nm PEG-BPNS, acting as "NanoMassage," significantly increase  plasma membrane tension, as evidenced by fluorescent lipid tension reporter fluorescence lifetime analysis. This mechanical force modulates actin reorganization, subsequently regulating the contacts between actin, mitochondria, and endoplasmic reticulum, further controlling mitochondrial fission and mitigating mitochondrial dysfunction in PD, exhibiting therapeutic efficacy via intranasal administration. These findings provide a noninvasive strategy for applying mechanical stimulation to deep brain areas and elucidate the mechanism of NanoMassage mediating inter-organelle contacts, suggesting the rational design of "NanoMassage" to remodel inter-organelle communications in neurodegenerative disease treatment.

Permeable Lung Vasculature Creates Chemoresistant Endothelial Niche by Producing SERPINE1 at Breast Cancer Metastatic Sites

Chemotherapy resistance remains a major obstacle for eradicating metastatic cancer cells in distant organs. We identified that endothelial cells (ECs) in the lungs, where breast cancer cells often metastasize, form a chemoresistant perivascular niche for disseminated breast cancer cells. By investigating the lung EC secretome activated by metastasis, we found that serine protease inhibitor family E member 1 (SERPINE1), encoded by Serpine1, is upregulated in metastasis-associated lung ECs. This upregulation shields cancer cells from paclitaxel-induced apoptosis and promotes cancer stem cell properties. Serpine1 expression appears to be driven by YAP-TEAD activation in lung ECs that lose cell-cell contact, a phenomenon associated with increased vascular permeability in lungs affected by metastasis. Crucially, pharmacological inhibition of SERPINE1 enhances the chemotherapy sensitivity of metastatic breast cancer cells in the lung. Overall, our findings underscore the pivotal role of the vascular niche, which produces SERPINE1, in conferring chemoresistance to breast cancer cells during metastatic progression in the lungs.

Matrix stiffening from collagen fibril density and alignment modulates YAP-mediated T-cell immune suppression

T-cells are essential components of the immune system, adapting their behavior in response to the mechanical environments they encounter within the body. In pathological conditions like cancer, the extracellular matrix (ECM) often becomes stiffer due to increased density and alignment of collagen fibrils, which can have a significant impact on T-cell function. In this study, we explored how these ECM properties-density and fibrillar alignment-affect T-cell behavior using three-dimensional (3D) collagen matrices that mimic these conditions. Our results show that increased matrix stiffness, whether due to higher density or alignment, significantly suppresses T-cell activation, reduces cytokine production, and limits proliferation, largely through enhanced YAP signaling. Individually, matrix alignment appears to lower actin levels in activated T-cells and changes migration behavior in both resting and activated T-cells, an effect not observed in matrices with randomly oriented fibrils. Notably, inhibiting YAP signaling was able to restore T-cell activation and improve immune responses, suggesting a potential strategy to boost the effectiveness of immunotherapy in stiff ECM environments. Overall, this study provides new insights into how ECM characteristics influence T-cell function, offering potential avenues for overcoming ECM-induced immunosuppression in diseases such as cancer.

Pannexin 1 crosstalk with the Hippo pathway in malignant melanoma

In this study, we explored the intricate relationship between Pannexin 1 (PANX1) and the Hippo signaling pathway effector, Yes-associated protein (YAP). Analysis of The Cancer Genome Atlas (TCGA) data revealed a significant positive correlation between PANX1 mRNA and core Hippo components, Yes-associated protein 1 [YAP], Transcriptional coactivator with PDZ-binding motif [TAZ], and Hippo scaffold, Ras GTPase-activating-like protein IQGAP1 [IQGAP1], in invasive cutaneous melanoma and breast carcinoma. Furthermore, we demonstrated that PANX1 expression is upregulated in invasive melanoma cell lines and is associated with increased YAP protein levels. Notably, our investigations uncovered a previously unrecognized interaction between endogenous PANX1 and the Hippo scaffold protein IQGAP1 in melanoma cells. Moreover, our findings revealed that IQGAP1 exhibits differential expression in melanoma cells and plays a regulatory role in cellular morphology. Functional studies involving PANX1 knockdown provided compelling evidence that PANX1 modulates YAP protein levels and its cotranscriptional activity in melanoma and breast carcinoma cells. Importantly, our study highlights the potential therapeutic significance of targeting PANX1. Pharmacological inhibition of PANX1 using selective FDA-approved inhibitors or PANX1 knockdown reduced YAP levels in melanoma cells. Furthermore, our Clariom™ S analysis unveiled key genes implicated in cell proliferation, such as neuroglin1 (NRG1), β-galactoside binding protein and galectin-3 (LGALS3), that are affected in PANX1-deficient cells. In summary, our investigation delves into the intricate interplay between PANX1 and YAP in the context of invasive melanoma, offering valuable insights into potential therapeutic strategies for effective treatment.

An Agrin-YAP/TAZ Rigidity Sensing Module Drives EGFR-Addicted Lung Tumorigenesis

Despite epidermal growth factor receptor (EGFR) is a pivotal oncogene for several cancers, including lung adenocarcinoma (LUAD), how it senses extracellular matrix (ECM) rigidity remain elusive in the context of the increasing role of tissue rigidity on various hallmarks of cancer development. Here it is shown that EGFR dictates tumorigenic agrin expression in lung cancer cell lines, genetically engineered EGFR-driven mouse models, and human specimens. Agrin expression confers substrate stiffness-dependent oncogenic attributes to EGFR-reliant cancer cells. Mechanistically, agrin mechanoactivates EGFR through epidermal growth factor (EGF)-dependent and independent modes, thereby sensitizing its activity toward localized cancer cell-ECM adherence and bulk rigidity by fostering interactions with integrin β1. Notably, a feed-forward loop linking agrin-EGFR rigidity response to YAP-TEAD mechanosensing is essential for tumorigenesis. Together, the combined inhibition of EGFR-YAP/TEAD may offer a strategy to reduce lung tumorigenesis by disrupting agrin-EGFR mechanotransduction, uncovering a therapeutic vulnerability for EGFR-addicted lung cancers.

[Research progress on collagen secretion mechanisms in scarring]

Scar formation is characterized by dynamic alterations in collagen secretion, which critically determine scar morphology and pathological progression. In fibroblasts, collagen secretion is initiated through the activation of cytokine- and integrin-mediated signaling pathways, which promote collagen gene transcription. The procollagen polypeptide α chains undergo extensive post-translational modifications, including hydroxylation and glycosylation, within the endoplasmic reticulum (ER), followed by folding and assembly into triple-helical procollagen. Subsequent intracellular trafficking involves the sequential transport of procollagen through the ER, Golgi apparatus, and plasma membrane, accompanied by further structural refinements prior to extracellular secretion. Once secreted, procollagen is enzymatically processed to form mature collagen fibrils, which drive scar tissue remodeling. Recent advances in elucidating regulation of collagen secretion have identified pivotal molecular targets, such as transforming growth factor-beta 1 (TGF-β1), prolyl 4-hydroxylase (P4H), heat shock protein 47 (HSP47), and transport and Golgi organization protein 1 (TANGO1), providing novel therapeutic strategies to mitigate pathological scar hyperplasia and improve regenerative outcomes. This review provides a comprehensive analysis of the molecular mechanisms governing collagen secretion during scar formation, with emphasis on signaling cascades, procollagen biosynthesis, intracellular transport dynamics, and post-translational modifications, thereby offering a framework for developing targeted anti-scar therapies.

Morphogenesis and regeneration share a conserved core transition cell state program that controls lung epithelial cell fate

Transitional cell states are at the crossroads of crucial developmental and regenerative events, yet little is known about how these states emerge and influence outcomes. The alveolar and airway epithelia arise from distal lung multipotent progenitors, which undergo cell fate transitions to form these distinct compartments. The identification and impact of cell states in the developing lung are poorly understood. Here, we identified a population of Icam1/Nkx2-1 epithelial progenitors harboring a transitional state program remarkably conserved in humans and mice during lung morphogenesis and regeneration. Lineage-tracing and functional analyses reveal their role as progenitors to both airways and alveolar cells and the requirement of this transitional program to make distal lung progenitors competent to undergo airway cell fate specification. The identification of a common progenitor cell state in vastly distinct processes suggests a unified program reiteratively regulating outcomes in development and regeneration.

Decoupling of Density-Dependent Migration/Proliferation Dichotomy on Surface Potential Gradient

The reciprocal connection between cell migration and proliferation relies on the intertwined contributions from substrate-associated and intercellular cues in the microenvironment. However, how cells perceive the substrates, make contact with their neighbors, and switch phenotypes under different trade-off conditions are still not fully understood. Here, we designed a distinct heterogeneous electric surface potential gradient of piezoelectric biomaterials to decouple the density-dependent migration/proliferation dichotomy. We found that the surface potential gradient accelerated both individual and collective cell migration but reduced proliferation through G0/G1 cell cycle arrest via the integrin/cytoskeleton signaling axis in low density. Interestingly, the initial cell density encodes the proliferative potential independent of the substrate feature. While in high density, the surface potential gradient ceased cell proliferation mainly via the E-cadherin/β-catenin signaling axis. Taken together, these results shed light on the underlying mechanism of the intertwined contributions of cell-material and cell-cell cross-links on migration and proliferation and also provide a new paradigm of materiobiology.

Electrospun meshes for abdominal wall hernia repair: Potential and challenges

Surgical meshes are widely used in abdominal wall hernia repairs. However, consensus on mesh treatment remains elusive due to varying repair outcomes, especially with the introduction of new meshes, posing a substantial challenge for surgeons. Addressing these issues requires communicating the features of emerging candidates with a focus on clinical considerations. Electrospinning is a versatile technique for producing meshes with biomechanical architectures that closely mimic the extracellular matrix and enable incorporation of bioactive and therapeutic agents into the interconnective porous network, providing a favorable milieu for tissue integration and remodeling. Although this promising technique has drawn considerable interest in mesh fabrication and functionalization, currently developed electrospun meshes have limitations in meeting clinical requirements for hernia repair. This review summarizes the advantages and limitations of meshes prepared through electrospinning based on biomechanical, biocompatible, and bioactive properties/functions, offering interdisciplinary insights into challenges and future directions toward clinical mesh-aided hernia repair. STATEMENT OF SIGNIFICANCE: Consensus for hernia treatments using surgical meshes remains elusive based on varying repair outcomes, presenting significant challenges for researchers and surgeons. Differences in understanding mesh between specialists, particularly regarding material characteristics and clinical requirements, contribute to this issue. Electrospinning has been increasingly applied in mesh preparation through various approaches and strategies, aiming to improve abdominal wall hernia by restoring mechanical, morphological and functional integrity. However, there is no comprehensive overview of these emerging meshes regarding their features, functions, and clinical potentials, emphasizing the necessity of interdisciplinary discussions on this topic that build upon recent developments in electrospun mesh and provide insights from clinically practical prospectives.

TRPML1 ion channel promotes HepaRG cell differentiation under simulated microgravity conditions

Stem cell differentiation must be regulated by intricate and complex interactions between cells and their surrounding environment, ensuring normal organ and tissue morphology such as the liver1. Though it is well acknowledged that microgravity provides necessary mechanical force signals for cell fate2, how microgravity affects growth, differentiation, and communication is still largely unknown due to the lack of real experimental scenarios and reproducibility tools. Here, Rotating Flat Chamber (RFC) was used to simulate ground-based microgravity effects to study how microgravity effects affect the differentiation of HepaRG (hepatic progenitor cells) cells. Unexpectedly, the results show that RFC conditions could promote HepaRG cell differentiation which exhibited increased expression of Alpha-fetoprotein (AFP), albumin (ALB), and Recombinant Cytokeratin 18 (CK18). Through screening a series of mechanical receptors, the ion channel TRPML1 was critical for promoting the differentiation effect under RFC conditions. Once TRPML1 was activated by stimulated microgravity effects, the concentration of lysosomal calcium ions was increased to activate the Wnt/β-catenin signaling pathway, which finally led to enhanced cell differentiation of HepaRG cells. In addition, the cytoskeleton was remodeled under RFC conditions to influence the expression of PI (3,5) P2, which is the best-known activator of TRPML1. In summary, our findings have established a mechanism by which simulated microgravity promotes the differentiation of HepaRG cells through the TRPML1 signaling pathway, which provides a potential target for the regulation of hepatic stem/progenitor cell differentiation and embryonic liver development under real microgravity conditions.

Nanoscale distribution of bioactive ligands on biomaterials regulates cell mechanosensing through translocation of actin into the nucleus

Cells respond to adhesive ligands such as arginine-glycine-aspartate (RGD) through integrins, which regulates cellular activities via influencing cytoskeleton assembly. Herein, we report that the nanoscale distribution of active ligands on biomaterials regulates cells through not only cytoplasmic tension but also nuclear tension. This is particularly related to translocation of actin into nucleus and highlighted in our interpretation of an "abnormal" phenomenon that large RGD nanospacing (>70 nm) disassembles integrin clusters, inhibits cell adhesion, but promotes osteogenic differentiation of mesenchymal stem cells. Our studies reveal that the unstable adhesion at the 150 nm RGD distance increases actin dynamics, resulting in the nuclear translocation of globular (G) actin. The compartment polymerization of more G-actins to filamentous actins in nucleus increases nuclear tension, facilitating transcription activity and releasing calcium ions from the endoplasmic reticulum. This noncanonical mechanotransduction process sheds insight into mechanotransduction pertinent to cell-material interactions.

Distinct effects of Hippo-YAP/TAZ and YAP/TAZ-TEAD in epithelial maintenance and repair

The maintenance of epithelial homeostasis is essential for preserving tissue architecture and function, and the transcriptional co-activators YAP/TAZ are central to this regulatory network. Although the Hippo-YAP/TAZ-TEAD axis is known to govern epithelial integrity, it remains unclear to what extent Hippo-controlled YAP/TAZ activity overlaps with, or diverges from, YAP/TAZ-TEAD-dependent transcriptional programs in maintaining epithelial homeostasis. Here, we address this question by employing two complementary mouse models: "SuperHippo," which suppresses YAP/TAZ activity through enhanced Hippo pathway engagement, and "TEADi," which selectively disrupts YAP/TAZ-TEAD interactions. Our results revealed that while both models led to increased epithelial thickness in skin epithelial, SuperHippo mice exhibited pronounced epithelial impairment in oral mucosa, and markedly delayed wound healing. In contrast, TEADi mice displayed tissue-specific phenotypes with minimal disruption to oral epithelium integrity or wound repair. These findings indicate that Hippo-mediated YAP/TAZ regulation may extend beyond TEAD-dependent transcription. Our work clarifies the distinct contributions of Hippo-YAP/TAZ signaling and YAP/TAZ-TEAD interaction to epithelial maintenance and provides a basis for the development of therapeutic strategies targeting YAP/TAZ in epithelial disorders.

The Hippo pathway: Organ size control and beyond

The Hippo signaling pathway is a highly conserved signaling network for controlling organ size, tissue homeostasis, and regeneration. It integrates a wide range of intracellular and extracellular signals, such as cellular energy status, cell density, hormonal signals, and mechanical cues, to modulate the activity of YAP/TAZ transcriptional coactivators. A key aspect of Hippo pathway regulation involves its spatial organization at the plasma membrane, where upstream regulators localize to specific membrane subdomains to regulate the assembly and activation of the pathway components. This spatial organization is critical for the precise control of Hippo signaling, as it dictates the dynamic interactions between pathway components and their regulators. Recent studies have also uncovered the role of biomolecular condensation in regulating Hippo signaling, adding complexity to its control mechanisms. Dysregulation of the Hippo pathway is implicated in various pathological conditions, particularly cancer, where alterations in YAP/TAZ activity contribute to tumorigenesis and drug resistance. Therapeutic strategies targeting the Hippo pathway have shown promise in both cancer treatment, by inhibiting YAP/TAZ signaling, and regenerative medicine, by enhancing YAP/TAZ activity to promote tissue repair. The development of small molecule inhibitors targeting the YAP-TEAD interaction and other upstream regulators offers new avenues for therapeutic intervention. SIGNIFICANCE STATEMENT: The Hippo signaling pathway is a key regulator of organ size, tissue homeostasis, and regeneration, with its dysregulation linked to diseases such as cancer. Understanding this pathway opens new possibilities for therapeutic approaches in regenerative medicine and oncology, with the potential to translate basic research into improved clinical outcomes.

Role of TGF-β/SMAD/YAP/TAZ signaling in skeletal muscle fibrosis

Skeletal muscle fibrosis is strongly associated with the differentiation of its resident multipotent fibro/adipogenic progenitors (FAPs) toward the myofibroblast phenotype. Although transforming growth factor type β (TGF-β) signaling is well-known for driving FAPs differentiation and fibrosis, due to its pleiotropic functions its complete inhibition is not suitable for treating fibrotic disorders such as muscular dystrophies. Here, we describe that TGF-β operates through the mechanosensitive transcriptional regulators Yes-associated protein (YAP)/ transcriptional coactivator with PDZ-binding motif (TAZ) to determine the myofibroblast fate of FAPs and skeletal muscle fibrosis. Spatial transcriptomics analyses of dystrophic and acute injured muscles showed that areas with active fibrosis and TGF-β signaling displayed high YAP/TAZ activity. Using a TGF-β-driven fibrotic mouse model, we found that activation of YAP/TAZ in activated FAPs is associated with the fibrotic process. Mechanistically, primary culture of FAPs reveals the remarkable ability of TGF-β1 to activate YAP/TAZ through its canonical SMAD3 pathway. Moreover, inhibition of YAP/TAZ, either by disrupting its activity (with Verteporfin) or cellular mechanotransduction (with the Rho inhibitor C3 or soft matrices), decreased TGF-β1-dependent FAPs differentiation into myofibroblasts. In vivo, administration of Verteporfin in mice limits the deposition of collagen and fibronectin, and the activation of FAPs during the development of fibrosis. Overall, our work provides robust evidence for considering YAP/TAZ as a potential target in muscular fibroproliferative disorders.NEW & NOTEWORTHY The understanding of the nuclear factors governing the differentiation of muscular fibro/adipogenic progenitors (FAPs) into myofibroblasts is in its infancy. Here, we comprehensively elucidate the status, regulation, and role of the mechanotransducers Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) in the muscular fibrotic process. Our findings reveal that inhibiting cellular mechanotransduction limits FAP differentiation and the extent of muscular fibrosis exerted by transforming growth factor type β (TGF-β). This research shed new lights on the molecular mechanisms dictating the cell fate of FAPs and the muscular fibrosis.

Mechanical compressive forces increase PI3K output signaling in breast and pancreatic cancer cells

Mechanical stresses, including compression, arise during cancer progression. In solid cancer, especially breast and pancreatic cancers, the rapid tumor growth and the environment remodeling explain their high intensity of compressive forces. However, the sensitivity of compressed cells to targeted therapies remains poorly known. In breast and pancreatic cancer cells, pharmacological PI3K inactivation decreased cell number and induced apoptosis. These effects were accentuated when we applied 2D compression forces in mechanically responsive cells. Compression selectively induced the overexpression of PI3K isoforms and PI3K/AKT pathway activation. Furthermore, transcriptional effects of PI3K inhibition and compression converged to control the expression of an autophagy regulator, GABARAP, whose level was inversely associated with PI3K inhibitor sensitivity under compression. Compression alone blocked autophagy flux in all tested cells, whereas inactivation of basal PI3K activity restored autophagy flux only in mechanically non-responsive compressed cells. This study provides direct evidence for the role of the PI3K/AKT pathway in compression-induced mechanotransduction. PI3K inhibition promotes apoptosis or autophagy, explaining PI3K importance to control cancer cell survival under compression.

The Role of Yes-Associated Protein in Inflammatory Diseases and Cancer

Yes-associated protein (YAP) plays a central role in the Hippo pathway, primarily governing cell proliferation, differentiation, and apoptosis. Its significance extends to tumorigenesis and inflammatory conditions, impacting disease initiation and progression. Given the increasing relevance of YAP in inflammatory disorders and cancer, this study aims to elucidate its pathological regulatory functions in these contexts. Specifically, we aim to investigate the involvement and molecular mechanisms of YAP in various inflammatory diseases and cancers. We particularly focus on how YAP activation, whether through Hippo-dependent or independent pathways, triggers the release of inflammation and inflammatory mediators in respiratory, cardiovascular, and digestive inflammatory conditions. In cancer, YAP not only promotes tumor cell proliferation and differentiation but also modulates the tumor immune microenvironment, thereby fostering tumor metastasis and progression. Additionally, we provide an overview of current YAP-targeted therapies. By emphasizing YAP's role in inflammatory diseases and cancer, this study aims to enhance our understanding of the protein's pivotal involvement in disease processes, elucidate the intricate pathological mechanisms of related diseases, and contribute to future drug development strategies targeting YAP.

Focus on mechano-immunology: new direction in cancer treatment

The immune response is modulated by a diverse array of signals within the tissue microenvironment, encompassing biochemical factors, mechanical forces, and pressures from adjacent tissues. Furthermore, the extracellular matrix and its constituents significantly influence the function of immune cells. In the case of carcinogenesis, changes in the biophysical properties of tissues can impact the mechanical signals received by immune cells, and these signals c1an be translated into biochemical signals through mechano-transduction pathways. These mechano-transduction pathways have a profound impact on cellular functions, influencing processes such as cell activation, metabolism, proliferation, and migration, etc. Tissue mechanics may undergo temporal changes during the process of carcinogenesis, offering the potential for novel dynamic levels of immune regulation. Here, we review advances in mechanoimmunology in malignancy studies, focusing on how mechanosignals modulate the behaviors of immune cells at the tissue level, thereby triggering an immune response that ultimately influences the development and progression of malignant tumors. Additionally, we have also focused on the development of mechano-immunoengineering systems, with the help of which could help to further understand the response of tumor cells or immune cells to alterations in the microenvironment and may provide new research directions for overcoming immunotherapeutic resistance of malignant tumors.

Decoding chromosomal instability insights in CRC by integrating omics and patient-derived organoids

BACKGROUND

Chromosomal instability (CIN) is involved in about 70% of colorectal cancers (CRCs) and is associated with poor prognosis and drug resistance. From a clinical perspective, a better knowledge of these tumour's biology will help to guide therapeutic strategies more effectively.

METHODS

We used high-density chromosomal microarray analysis to evaluate CIN level of patient-derived organoids (PDOs) and their original mCRC tissues. We integrated the RNA-seq and mass spectrometry-based proteomics data from PDOs in a functional interaction network to identify the significantly dysregulated processes in CIN. This was followed by a proteome-wGII Pearson correlation analysis and an in silico validation of main findings using functional genomic databases and patient-tissues datasets to prioritize the high-confidence CIN features.

RESULTS

By applying the weighted Genome Instability Index (wGII) to identify CIN, we classified PDOs and demonstrated a good correlation with tissues. Multi-omics analysis showed that our organoids recapitulated genomic, transcriptomic and proteomic CIN features of independent tissues cohorts. Thanks to proteotranscriptomics, we uncovered significant associations between mitochondrial metabolism and epithelial-mesenchymal transition in CIN CRC PDOs. Correlating PDOs wGII with protein abundance, we identified a subset of proteins significantly correlated with CIN. Co-localisation analysis in PDOs strengthened the putative role of IPO7 and YAP, and, through in silico analysis, we found that some of the targets give significant dependencies in cell lines with CIN compatible status.

CONCLUSIONS

We first demonstrated that PDO models are a faithful reflection of CIN tissues at the genetic and phenotypic level. Our new findings prioritize a subset of genes and molecular processes putatively required to cope with the burden on cellular fitness imposed by CIN and associated with disease aggressiveness.

Keratin 15 promotes a progenitor cell state in basal keratinocytes of skin epidermis

The type I intermediate filament proteins keratin 14 (K14) and keratin 15 (K15) are common to all complex epithelia. K14 is highly expressed by progenitor keratinocytes, in which it provides essential mechanical integrity and gates keratinocyte entry into differentiation by sequestering YAP1, a transcriptional effector of Hippo signaling, to the cytoplasm. K15 has long been used as a marker of hair bulge stem cells though its specific role in skin epithelia is unknown. Here we show that the lack of two biochemical determinants, a cysteine residue within the stutter motif of the central rod domain and a 14-3-3 binding site in the N-terminal head domain, renders K15 unable to effectively sequester YAP1 in the cytoplasm. We combine insight obtained from cell culture and transgenic mouse models with computational analyses of transcriptomics data and propose a model in which the K15:K14 ratio promotes a progenitor state and antagonizes differentiation in keratinocytes of the epidermis.

The Hidden Power of the Secretome: Therapeutic Potential on Wound Healing and Cell-Free Regenerative Medicine-A Systematic Review

Various types of wounds represent a persistent healthcare burden that demands innovative and effective therapeutic solutions. Innovative approaches have emerged that focus on skin regeneration with minimal side effects. One such method is cell-free therapy that utilizes the secretome of human mesenchymal stem cells (hMSCs) as a promising alternative to traditional cell-based therapies, leveraging a complex mixture of bioactive molecules, including growth factors, cytokines, and extracellular vesicles, to accelerate tissue regeneration. This systematic review synthesizes the findings of 35 studies evaluating the impact of hMSC-derived secretomes on wound healing, with a focus on their regenerative, immunomodulatory, and angiogenic effects. The influence of MSC sources (adipose tissue, bone marrow, umbilical cord) and culture conditions on secretome composition and efficacy in the cutaneous wound healing process is examined, highlighting their therapeutic potential in regenerative medicine. This review also explores emerging preclinical and clinical applications, highlighting promising results, such as enhanced fibroblast proliferation, reduced inflammation, and improved extracellular matrix remodeling. In addition, advances in secretome-based biomaterials, including hydrogels and scaffolds, which optimize therapeutic delivery and efficacy are discussed. Despite the growing body of evidence supporting the safety and efficacy of secretomes, challenges remain regarding standardization, large-scale production, and clinical validation. This review highlights the potential of MSC-derived secretomes as a next-generation cell-free approach for wound healing and regenerative medicine.

UFMylation maintains YAP stability to promote vascular endothelial cell senescence

Endothelial cell (EC) senescence is an accomplice for vascular aging, which leads to cardiovascular diseases (CVDs). Evidences showed that Hippo-Yes-associated protein (YAP) signaling pathway plays an essential role in aging-associated CVDs. Here, we reported that YAP was elevated in senescent human umbilical vein endothelial cells (HUVECs) and inhibition of YAP could attenuate HUVECs senescence. Besides, our findings revealed that the activity of UFMylation and the level of YAP were both elevated in senescent cells. Furthermore, UFM1-modified YAP was upregulated in senescent ECs, and increased the stability of YAP. Importantly, we found that compound 8.5, an inhibitor of E1 of UFMylation, can alleviate vascular aging in aged mice. Together, our finding provides molecular mechanism by which UFMylation maintains YAP stability and exerts an important role in promoting cell senescence, and identified that a previously unrecognized UFMylation is a potential therapeutic target for anti-aging.

VGLL2 and TEAD1 fusion proteins drive YAP/TAZ-independent tumorigenesis by engaging p300

Studies on Hippo pathway regulation of tumorigenesis largely center on YAP and TAZ, the transcriptional co-regulators of TEAD. Here, we present an oncogenic mechanism involving VGLL and TEAD fusions that is Hippo pathway-related but YAP/TAZ-independent. We characterize two recurrent fusions, VGLL2-NCOA2 and TEAD1-NCOA2, recently identified in spindle cell rhabdomyosarcoma. We demonstrate that in contrast to VGLL2 and TEAD1, the fusion proteins are strong activators of TEAD-dependent transcription, and their function does not require YAP/TAZ. Furthermore, we identify that VGLL2 and TEAD1 fusions engage specific epigenetic regulation by recruiting histone acetyltransferase p300 to control TEAD-mediated transcriptional and epigenetic landscapes. We showed that small molecule p300 inhibition can suppress fusion proteins-induced oncogenic transformation both in vitro and in vivo. Overall, our study reveals a molecular basis for VGLL involvement in cancer and provides a framework for targeting tumors carrying VGLL, TEAD, or NCOA translocations.

Cell enlargement modulated by GATA4 and YAP instructs the senescence-associated secretory phenotype

Dynamic changes in cell size are associated with development and pathological conditions, including aging. Although cell enlargement is a prominent morphological feature of cellular senescence, its functional implications are unknown; moreover, how senescent cells maintain their enlargement state is less understood. Here we show that an extensive remodeling of actin cytoskeleton is necessary for establishing senescence-associated cell enlargement and pro-inflammatory senescence-associated secretory phenotype (SASP). This remodeling is attributed to a balancing act between the SASP regulator GATA4 and the mechanosensor YAP on the expression of the Rho family of GTPase RHOU. Genetic or pharmacological interventions that reduce cell enlargement attenuate SASP with minimal effect on senescence growth arrest. Mechanistically, actin cytoskeleton remodeling couples cell enlargement to the nuclear localization of GATA4 and NF-κB via the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex. RhoU protein accumulates in mouse adipose tissue under senescence-inducing conditions. Furthermore, RHOU expression correlates with SASP expression in adipose tissue during human aging. Thus, our study highlights an unexpected instructive role of cell enlargement in modulating the SASP and reveals a mechanical branch in the senescence regulatory network.

Expression of foetal gene Pontin is essential in protecting heart against pathological remodelling and cardiomyopathy

Cardiac remodelling is a key process in the development of heart failure. Reactivation of foetal cardiac genes is often associated with cardiac remodelling. Here we study the role of Pontin (Ruvbl1), which is highly expressed in embryonic hearts, in mediating adverse remodelling in adult mouse hearts. We observe that Pontin deficiency in cardiomyocytes leads to induced apoptosis, increased hypertrophy and fibrosis, whereas Pontin overexpression improves survival, increases proliferation and reduces the hypertrophic response. Moreover, RNAseq analysis show that genes involved in cell cycle regulation, cell proliferation and cell survival/apoptosis are differentially expressed in Pontin knockout. Specifically, we detect changes in the expression of Hippo pathway components in the Pontin knockout mice. Using a cellular model we show that Pontin induces YAP activity, YAP nuclear translocation, and transcriptional activity. Our findings identify Pontin as a modulator of adverse cardiac remodelling, possibly via regulation of the Hippo pathway. This study may lead to the development of a new approach to control cardiac remodelling by targeting Pontin.

The Moonlighting Function of Glutaminase 2 Promotes Immune Evasion of Pancreatic Ductal Adenocarcinoma by Tubulin Tyrosine Ligase-like 1-Mediated Yes1 Associated Transcriptional Regulator Glutamylation

BACKGROUND & AIMS

Elevated programmed cell death-ligand 1 (PD-L1) expression in tumor cells facilitates immune evasion. However, the mechanism via which PD-L1 expression is regulated in pancreatic ductal adenocarcinoma (PDAC) cells remains inadequately elucidated.

METHODS

Immunoprecipitation, pull-down assays, and mass spectrometry were used to identify glutaminase 2 (GLS2) and yes1 associated transcriptional regulator (YAP1) binding proteins and modification sites. Immunoblotting, immunofluorescence, chromatin immunoprecipitation, and luciferase reporter assays were used to analyze YAP1 activation. Protein expression levels were assessed using immunoblotting, immunoprecipitation, immunofluorescence, and immunohistochemistry. RNA expression levels were analyzed using real-time quantitative polymerase chain reaction.

RESULTS

Hypoxia-induced general control nondepressible 5 (GCN5)-mediated acetylation of GLS2 at K151, which enhanced GLS2 interaction with YAP1. Subsequently, tubulin tyrosine ligase-like 1 mediated YAP1 glutamylation at E100 and promoted its nuclear translocation and the activation-dependent transcriptional up-regulation of PD-L1 expression. The expression of GLS2-K151R or YAP1-E100A mutants in PDAC cells blocked hypoxia-induced PD-L1 expression and enhanced CD4+ and CD8+ T-cell activation and tumor infiltration, thereby suppressing PDAC tumor growth. Simultaneous administration of MB-3, a GCN5 inhibitor, and an anti-programmed cell death 1 (PD-1) antibody abolished tumor immune evasion, boosting the anti-tumor efficacy of immune checkpoint blockade. Furthermore, GLS2-K151 acetylation and YAP1 E100 glutamylation levels correlated positively with PD-L1 expression and poor prognosis in PDAC patients.

CONCLUSIONS

The present study revealed a novel mechanism by which hypoxia up-regulates PD-L1 expression and highlighted the involvement of GLS2 in noncanonical metabolic pathways involved in tumor immune evasion, with implications for PDAC treatment.

Hippo-YAP signaling alleviates copper-induced mitochondrial dysfunction and oxidative damage via the ATOX1-PPA2 pathway

Hippo signaling plays a crucial role in the cellular response to various stressors, such as mechanical stress, metabolic stress, and hypoxic stress. However, its physiological significance in copper (Cu) stress remains poorly understood. Here, we demonstrated aberrant activation of Hippo-YAP signaling in sheep pancreas and pancreatic organoids exposed to excessive Cu, accompanied by significant pathological changes, elevated levels of oxidative stress, and impaired mitochondrial structure and function. The inhibition of Hippo signaling or overexpression of YAP protected against Cu-induced damage by improving mitochondrial function and maintaining cellular Cu homeostasis. YAP interacted with TEAD and upregulated the expression of Cu chaperone ATOX1, a key regulator of intracellular Cu homeostasis. ATOX1 restored mitochondrial function under Cu stress by reducing mitochondrial superoxide levels, increasing ATP production and mitochondrial membrane potential. Additionally, our findings confirmed that ATOX1 indirectly bound to the PPA2 promoter and increased its transcription. Notably, the restoration of ATP production in mitochondria mediated by PPA2 overexpression facilitated efficient intracellular Cu efflux, allowing rapid and precise reestablishment of intracellular Cu homeostasis under Cu stress. Collectively, Hippo-YAP signaling alleviates Cu-induced oxidative damage by restoring mitochondrial function through activation of PPA2 transcription depending on ATOX1, thereby ensuring cellular Cu efflux and enhancing antioxidant capacity.

The Role of the Swollen State in Cell Proliferation

Cell swelling is known to be involved in various stages of the growth of plant cells and microorganisms but in mammalian cells how crucial a swollen state is for determining the fate of the cellular proliferation remains unclear. Recent evidence has increased our understanding of how the loss of the cell surface interactions with the extracellular matrix at early mitosis decreases the membrane tension triggering curvature changes in the plasma membrane and the activation of the sodium/hydrogen (Na +/H +) exchanger (NHE1) that drives osmotic swelling. Such a swollen state is temporary, but it is critical to alter essential membrane biophysical parameters that are required to activate Ca2 + channels and modulate the opening of K + channels involved in setting the membrane potential. A decreased membrane potential across the mitotic cell membrane enhances the clustering of Ras proteins involved in the Ca2 + and cytoskeleton-driven events that lead to cell rounding. Changes in the external mechanical and osmotic forces also have an impact on the lipid composition of the plasma membrane during mitosis.

Amphiregulin Downregulates E-cadherin Expression by Activating YAP/Egr-1/Slug Signaling in SKOV3 Human Ovarian Cancer Cells

Amphiregulin (AREG) stimulates human epithelial ovarian cancer (EOC) cell invasion by downregulating E-cadherin expression. YAP is a transcriptional cofactor that has been shown to regulate tumorigenesis. This study aimed to examine whether AREG activates YAP in EOC cells and explore the roles of YAP in AREG-induced downregulation of E-cadherin and cell invasion. Analysis of the Cancer Genome Atlas (TCGA) showed that upregulation of AREG and EGFR were associated with poor survival in human EOC. Treatment of SKOV3 human EOC cells with AREG induced the activation of YAP. In addition, AREG downregulated E-cadherin, upregulated Egr-1 and Slug, and stimulated cell invasion. Using gain- and loss-of-function approaches, we showed that YAP was required for the AREG-upregulated Egr-1 and Slug expression. Furthermore, YAP was also involved in AREG-induced downregulation of E-cadherin and cell invasion. This study provides evidence that AREG stimulates human EOC cell invasion by downregulating E-cadherin expression through the YAP/Egr-1/Slug signaling.

Novel techniques to quantitatively assess age-dependent alterations in biophysical properties of HSPCs and bone marrow niche

The present knowledge on hematopoietic stem and progenitor cell (HSPC) biology and aging is based largely on studies in mouse models. Although mouse models are invaluable, they are not without limitations for defining how physical properties of HSPCs and their niche change with age. The bone marrow (BM) niche is a complex, interactive environment with multiple cell types. The structure and organization of the BM niche, especially the extracellular matrix (ECM), change with age. Provided with recent advances in quantitative analytical techniques and in vitro niche models, we have developed novel tools to quantitatively assess the impact of specific biochemical and physical cues on homing, adhesion, and migration of HSPCs. Recent developments in in vitro niche models have also provided new insights into the interactions between HSPCs and their niche, particularly the role of matrix stiffness. Further research is needed to integrate physical biomarkers into comprehensive mathematical models of age-dependent HSPC-niche interactions. The key is to use mouse models in conjunction with direct analyses in in vitro niche models to achieve a more comprehensive understanding of age-dependent alterations in niche function and regulation.

Effects of Cell Seeding Density, Extracellular Matrix Composition, and Geometry on Yes-Associated Protein Translocation in Corneal Fibroblasts

Corneal fibroblasts are central to normal and abnormal wound healing in the cornea. During the wound healing process, several biochemical and biophysical signals that are present in the extracellular matrix (ECM) play critical roles in regulating corneal fibroblast behavior. The translocation and activation of Yes-associated protein (YAP)-a main transcriptional factor in the Hippo signaling pathway-is one example of mechanotransduction involving these signals. However, how corneal fibroblasts integrate these simultaneous cues is unknown. In this study, we utilized well-defined micropatterns of aligned collagen fibrils and other ECM proteins to explore the effects of cell density, topography, geometric confinement, and ECM composition on the translocation of YAP in corneal fibroblasts. We observed that when human corneal fibroblasts (HTKs) were confined to narrow micropatterns (50 μm and 100 μm) of proteins, there was a high degree of cell alignment irrespective of cell seeding density. However, the location of YAP was dependent upon the cell seeding density, ECM composition, and topography. YAP was more nuclear-localized on substrates coated with aligned collagen fibrils or fibronectin as compared to substrates coated with monomeric collagen, random collagen fibrils, or poly-L-Lysine. In addition, we also observed that YAP nuclear localization was significantly reduced when HTKs were cultured on aligned collagen fibrils, monomeric collagen, or fibronectin in the presence of monoclonal blocking antibodies against α5 or β1 integrin subunits. Finally, we observed that HTK cells formed fibrillar fibronectin on both monomeric collagen and aligned collagen fibrils. These findings provide new insights into how simultaneous biochemical and biophysical cues affect YAP localization in corneal fibroblasts.

Shaping epithelial tissues by stem cell mechanics in development and cancer

Adult stem cells balance self-renewal and differentiation to build, maintain and repair tissues. The role of signalling pathways and transcriptional networks in controlling stem cell function has been extensively studied, but there is increasing appreciation that mechanical forces also have a crucial regulatory role. Mechanical forces, signalling pathways and transcriptional networks must be coordinated across diverse length and timescales to maintain tissue homeostasis and function. Such coordination between stem cells and neighbouring cells dictates when cells divide, migrate and differentiate. Recent advances in measuring and manipulating the mechanical forces that act upon and are produced by stem cells are providing new insights into development and disease. In this Review, we discuss the mechanical forces involved when epithelial stem cells construct their microenvironment and what happens in cancer when stem cell niche mechanics are disrupted or dysregulated. As the skin has evolved to withstand the harsh mechanical pressures from the outside environment, we often use the stem cells of mammalian skin epithelium as a paradigm for adult stem cells shaping their surrounding tissues.

YAP/TAZ-associated cell signaling - at the crossroads of cancer and neurodevelopmental disorders

YAP/TAZ (Yes-associated protein/paralog transcriptional co-activator with PDZ-binding domain) are transcriptional cofactors that are the key and major downstream effectors of the Hippo signaling pathway. Both are known to play a crucial role in defining cellular outcomes, including cell differentiation, cell proliferation, and apoptosis. Aside from the canonical Hippo signaling cascade with the key components MST1/2 (mammalian STE20-like kinase 1/2), SAV1 (Salvador homologue 1), MOB1A/B (Mps one binder kinase activator 1A/B) and LATS1/2 (large tumor suppressor kinase 1/2) upstream of YAP/TAZ, YAP/TAZ activation is also influenced by numerous other signaling pathways. Such non-canonical regulation of YAP/TAZ includes well-known growth factor signaling pathways such as the epidermal growth factor receptor (EGFR)/ErbB family, Notch, and Wnt signaling as well as cell-cell adhesion, cell-matrix interactions and mechanical cues from a cell's microenvironment. This puts YAP/TAZ at the center of a complex signaling network capable of regulating developmental processes and tissue regeneration. On the other hand, dysregulation of YAP/TAZ signaling has been implicated in numerous diseases including various cancers and neurodevelopmental disorders. Indeed, in recent years, parallels between cancer development and neurodevelopmental disorders have become apparent with YAP/TAZ signaling being one of these pathways. This review discusses the role of YAP/TAZ in brain development, cancer and neurodevelopmental disorders with a special focus on the interconnection in the role of YAP/TAZ in these different conditions.