Liver regeneration and ethanol detoxification: A new link in YAP regulation of ALDH1A1 during alcohol-related hepatocyte damage

Development and evaluation of chitosan conjugated Isatin-linked Pyrazole derivative to target anti-inflammatory and anti-fibrotic in ethanol induced liver fibrosis using an in-vivo zebra fish model

Alcoholic liver disease (ALD) remains a health burden, characterized by hepatic steatosis to fibrosis, a significant contributor to global morbidity and mortality, with limited therapeutic options for advanced stages like liver fibrosis. This study explores the antifibrotic and anti-inflammatory potential of a novel isatin-linked pyrazole derivative (3F) conjugated with chitosan-EDTA (CS) in mitigating ethanol (EtOH) induced liver fibrosis in zebrafish model. We demonstrated hepatic fibrosis using a chronic low-dose EtOH model (0.2 %), mimicking the ALD stage. CS-3F conjugates were synthesized using ionotropic gelation, exhibiting optimal drug-loading capacity, sustained drug release, and enhanced bioavailability. Morphological characterization revealed particle sizes ranging from 50 to 300 nm, facilitating efficient cellular uptake and liver-targeted drug distribution. EtOH exposure significantly elevated hepatic biomarkers (ALT, AST, and ALP), disrupted lipid metabolism (TC and TG), and impaired detoxification functions (ammonia and urea metabolism). Oxidative stress and inflammation were evident, with decreased SOD and CAT levels, increased MDA and LDH levels, and upregulation of pro-inflammatory and fibrotic genes (il-1β, tnfα, tgf-β, col1a1, and fasn). Treatment with CS-3F significantly ameliorated these alterations, restoring metabolic, detoxification, antioxidant functions and significantly reducing inflammation and fibrosis. Histopathological analysis confirmed improvements in liver architecture, including reduced parenchymal damage and ECM deposition. These results highlight the utility of CS-3F in reversing fibrosis and restoring liver function, offering a promising avenue for addressing the unmet therapeutic needs in ALD. However, further studies are needed to validate these findings in mammalian models and elucidate the underlying molecular mechanisms.

Role of mitogens in normal and pathological liver regeneration

The liver has a unique ability to regenerate to meet the body's metabolic needs, even following acute or chronic injuries. The cellular and molecular mechanisms underlying normal liver regeneration have been well investigated to improve organ transplantation outcomes. Once liver regeneration is impaired, pathological regeneration occurs, and the underlying cellular and molecular mechanisms require further investigations. Nevertheless, a plethora of cytokines and growth factor-mediated pathways have been reported to modulate physiological and pathological liver regeneration. Regenerative mitogens play an essential role in hepatocyte proliferation. Accelerator mitogens in synergism with regenerative ones promote liver regeneration following hepatectomy. Finally, terminator mitogens restore the proliferating status of hepatocytes to a differentiated and quiescent state upon completion of regeneration. Chronic loss of hepatocytes, which can manifest in chronic liver disorders of any etiology, often has undesired structural consequences, including fibrosis, cirrhosis, and liver neoplasia due to the unregulated proliferation of remaining hepatocytes. In fact, any impairment in the physiological function of the terminator mitogens results in the progression of pathological liver regeneration. In the current review, we intend to highlight the updated cellular and molecular mechanisms involved in liver regeneration and discuss the impairments in central regulating mechanisms responsible for pathological liver regeneration.

CRISPR/Cas9 Targeting of Aldehyde Dehydrogenase 1A1 Reveals Heterogeneous Roles in Radiation Response and Redox Stress Across Clonal Lines in Triple-Negative Breast Cancer

The metabolic enzyme aldehyde dehydrogenase 1A1 (ALDH1A1), a cancer stem cell marker associated with poor outcomes in breast cancer, has emerged as a promising therapeutic target in TNBC. The aim of this study was to investigate the role of ALDH1A1 in radiation resistance and redox stress in triple negative breast cancer (TNBC). Functional knockouts of ALDH1A1 were generated by the CRISPR/Cas9-mediated deletion of ALDH1A1 in the SUM159 cell line, and three distinct clonal populations were isolated. Genetic targeting was confirmed by Sanger sequencing, and the loss of ALDH1A1 protein expression was validated by Western blotting. Functional assays assessed ALDEFLUOR activity, cell viability, self-renewal capacity, and reactive oxygen species (ROS) levels with or without radiation in both the bulk population and clonal lines. Interestingly, ALDEFLUOR activity was uniformly lost across all clonal lines; however, functional effects of ALDH1A1 loss on redox stress, survival, and radiation sensitivity were observed in only one clonal population. These findings highlight significant variability in the role of ALDH1A1 among clonal populations, reflecting the complexity of tumor heterogeneity. This underscores the importance of accounting for tumor heterogeneity when targeting ALDH1A1, as certain TNBC subpopulations may rely more heavily on ALDH1A1 function. These insights are critical for developing effective ALDH1A1-targeted therapies.

Optimization of culture conditions to generate vascularized multi-lineage liver organoids with structural complexity and functionality

Hepatic organoids (HOs), primarily composed of hepatobiliary cells, do not represent the pathogenesis of liver diseases due to the lack of non-parenchymal cells. Multi-lineage liver organoids (mLOs) containing various cell types found in the liver offer a promising in vitro disease model. However, their structural complexity remains challenging to achieve due to the difficulty in optimizing culture conditions that meet the growth need of all component cell types. Here, we demonstrate that cystic HOs generated from hPSCs can be expanded long-term and serve as a continuous source for generating complex mLOs. Assembling cystic HOs with hPSC-derived endothelial and hepatic stellate cell-like cells under conventional HO culture conditions failed to support the development of multiple cell types within mLOs, resulting in biased differentiation towards specific cell types. In contrast, modulating the cAMP/Wnt/Hippo signaling pathways with small molecules during assembly and differentiation phases efficiently generate mLOs containing both hepatic parenchymal and non-parenchymal cells. These mLOs exhibited structural complexity and functional maturity, including vascular network formation between parenchymal lobular structures, cell polarity for bile secretion, and the capacity to respond to fibrotic stimuli. Our study underscores the importance of modulating signaling pathways to enhance mLO structural complexity for applications in modeling liver pathologies.

Activity-based sensing reveals elevated labile copper promotes liver aging via hepatic ALDH1A1 depletion

Oxidative stress plays a key role in aging and related diseases, including neurodegeneration, cancer, and organ failure. Copper (Cu), a redox-active metal ion, generates reactive oxygen species (ROS), and its dysregulation contributes to aging. Here, we develop activity-based imaging probes for the sensitive detection of Cu(I) and show that labile hepatic Cu activity increases with age, paralleling a decline in ALDH1A1 activity, a protective hepatic enzyme. We also observe an age-related decrease in hepatic glutathione (GSH) activity through noninvasive photoacoustic imaging. Using these probes, we perform longitudinal studies in aged mice treated with ATN-224, a Cu chelator, and demonstrate that this treatment improves Cu homeostasis and preserves ALDH1A1 activity. Our findings uncover a direct link between Cu dysregulation and aging, providing insights into its role and offering a therapeutic strategy to mitigate its effects.

Molecular mechanisms in liver repair and regeneration: from physiology to therapeutics

Liver repair and regeneration are crucial physiological responses to hepatic injury and are orchestrated through intricate cellular and molecular networks. This review systematically delineates advancements in the field, emphasizing the essential roles played by diverse liver cell types. Their coordinated actions, supported by complex crosstalk within the liver microenvironment, are pivotal to enhancing regenerative outcomes. Recent molecular investigations have elucidated key signaling pathways involved in liver injury and regeneration. Viewed through the lens of metabolic reprogramming, these pathways highlight how shifts in glucose, lipid, and amino acid metabolism support the cellular functions essential for liver repair and regeneration. An analysis of regenerative variability across pathological states reveals how disease conditions influence these dynamics, guiding the development of novel therapeutic strategies and advanced techniques to enhance liver repair and regeneration. Bridging laboratory findings with practical applications, recent clinical trials highlight the potential of optimizing liver regeneration strategies. These trials offer valuable insights into the effectiveness of novel therapies and underscore significant progress in translational research. In conclusion, this review intricately links molecular insights to therapeutic frontiers, systematically charting the trajectory from fundamental physiological mechanisms to innovative clinical applications in liver repair and regeneration.

YAP/TAZ as master regulators in liver regeneration and disease: insights into mechanisms and therapeutic targets

Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are key downstream effectors of the Hippo pathway that regulate organ size, tissue homeostasis, and cancer development. YAP/TAZ play crucial regulatory roles in organ growth, cell proliferation, cell renewal, and regeneration. Mechanistically, YAP/TAZ influence the occurrence and progression of liver regeneration (LR) through various signaling pathways, including Notch, Wnt/β-catenin, TGF-β/Smad. While the activation of YAP/TAZ can promote the regeneration of damaged liver tissue, their mechanisms of action may differ under various LR conditions. Furthermore, excessive activation of YAP/TAZ may also lead to severe liver damage, manifesting as alcoholic hepatitis, liver fibrosis, and even liver cancer. Here, we review the role and mechanisms of YAP/TAZ in LR and liver disease, highlighting the potential for advancements in clinical diagnosis and treatment targeting YAP/TAZ in these contexts.

Redox-sensitive epigenetic activation of SUV39H1 contributes to liver ischemia-reperfusion injury

Liver ischemia-reperfusion (I/R) injury is a clinically relevant pathophysiological process that determines the effectiveness of life-saving liver transplantation, to which aberrant ROS accumulation plays a key role. In the present study we investigated the role of SUV39H1, a lysine methyltransferases, in this process focusing on regulatory mechanism and translational potential. We report that SUV39H1 expression was up-regulated in the liver tissues of mice subjected to ischemia-reperfusion and in hepatocytes exposed to hypoxia-reoxygenation (H/R) in a redox-sensitive manner. Mechanistically, coactivator associated arginine methyltransferases 1 (CARM1) mediated redox-sensitive Suv39h1 trans-activation by promoting histone H3R17 methylation. Consistently, pharmaceutical CARM1 inhibition attenuated liver I/R injury. In addition, global or hepatocyte conditional Suv39h1 KO mice were protected from liver I/R injury. RNA-seq revealed that aldehyde dehydrogenase 1 family 1a (Aldh1a1) as a novel target for SUV39H1. SUV39H1 directly bound to the Aldh1a1 promoter and repressed Aldh1a1 transcription in H/R-challenged hepatocytes. ALDH1A1 silencing abrogated the protective effects of SUV39H1 deficiency on H/R-inflicted injuries whereas ALDH1A1 over-expression mitigated liver I/R injury in mice. Importantly, administration of a small-molecule SUV39H1 inhibitor achieved similar hepatoprotective effects as SUV39H1 deletion. Finally, increased Suv39h1 expression and decreased Aldh1a1 expression were observed in liver I/R specimens in humans. In conclusion, our data uncover a regulatory role for SUV39H1 in liver I/R injury and serve as proof-of-concept that targeting the SUV39H1-ALDH1A1 axis might be considered as a reasonable approach for the intervention of liver I/R injury.

The Hippo Pathway in Breast Cancer: The Extracellular Matrix and Hypoxia

As one of the most prevalent malignant neoplasms among women globally, the optimization of therapeutic strategies for breast cancer has perpetually been a research hotspot. The tumor microenvironment (TME) is of paramount importance in the progression of breast cancer, among which the extracellular matrix (ECM) and hypoxia are two crucial factors. The alterations of these two factors are predominantly regulated by the Hippo signaling pathway, which promotes tumor invasiveness, metastasis, therapeutic resistance, and susceptibility. Hence, this review focuses on the Hippo pathway in breast cancer, specifically, how the ECM and hypoxia impact the biological traits and therapeutic responses of breast cancer. Moreover, the role of miRNAs in modulating ECM constituents was investigated, and hsa-miR-33b-3p was identified as a potential therapeutic target for breast cancer. The review provides theoretical foundations and potential therapeutic direction for clinical treatment strategies in breast cancer, with the aspiration of attaining more precise and effective treatment alternatives in the future.

Multi-Omics profiling identifies aldehyde dehydrogenase 2 as a critical mediator in the crosstalk between Treg-mediated immunosuppression microenvironment and hepatocellular carcinoma

Dysregulation of the aldehyde dehydrogenase (ALDH) family has been implicated in various pathological conditions, including cancer. However, a systematic evaluation of ALDH alterations and their therapeutic relevance in hepatocellular carcinoma (HCC) remains lacking. Herein, we found that 15 of 19 ALDHs were transcriptionally dysregulated in HCC tissues compared to normal liver tissues. A four gene signature, including ALDH2, ALDH5A1, ALDH6A1, and ALDH8A1, robustly predicted prognosis and defined a high-risk subgroup exhibiting immunosuppressive features like regulatory T cell (Tregs) infiltration. Single-cell profiling revealed selective overexpression of tumor necrosis factor receptor superfamily member 18 (TNFRSF18) on Tregs, upregulated in high-risk HCC patients. We identified ALDH2 as a tumor suppressor in HCC, with three novel phosphorylation sites mediated by protein kinase C zeta that enhanced enzymatic activity. Mechanistically, ALDH2 suppressed Tregs differentiation by inhibiting β-catenin/TGF-β1 signaling in HCC. Collectively, our integrated multi-omics analysis defines an ALDH-Tregs-TNFRSF18 axis that contributes to HCC pathogenesis and represents potential therapeutic targets for this aggressive malignancy.

Amniotic Membrane and Its Derivatives: Novel Therapeutic Modalities in Liver Disorders

The liver is a vital organ responsible for metabolic and digestive functions, protein synthesis, detoxification, and numerous other necessary functions. Various acute, chronic, and neoplastic disorders affect the liver and hamper its biological functions. Most of the untreated liver diseases lead to inflammation and fibrosis which develop into cirrhosis. The human amniotic membrane (hAM), the innermost layer of the fetal placenta, is composed of multiple layers that include growth-factor rich basement membrane, epithelial and mesenchymal stromal cell layers. hAM possesses distinct beneficial anti-fibrotic, anti-inflammatory and pro-regenerative properties via the secretion of multiple potent trophic factors and/or direct differentiation into hepatic cells which place hAM-based therapies as potential therapeutic strategies for the treatment of chronic liver diseases. Decellularized hAM is also an ideal scaffold for liver tissue engineering as this biocompatible niche provides an excellent milieu for cell proliferation and hepatocytic differentiation. Therefore, the current review discusses the therapeutic potential of hAM and its derivatives in providing therapeutic solutions for liver pathologies including acute liver failure, metabolic disorders, liver fibrosis as well as its application in liver tissue engineering.

YAP/TAZ: Molecular pathway and disease therapy

The Yes-associated protein and its transcriptional coactivator with PDZ-binding motif (YAP/TAZ) are two homologous transcriptional coactivators that lie at the center of a key regulatory network of Hippo, Wnt, GPCR, estrogen, mechanical, and metabolism signaling. YAP/TAZ influences the expressions of downstream genes and proteins as well as enzyme activity in metabolic cycles, cell proliferation, inflammatory factor expression, and the transdifferentiation of fibroblasts into myofibroblasts. YAP/TAZ can also be regulated through epigenetic regulation and posttranslational modifications. Consequently, the regulatory function of these mechanisms implicates YAP/TAZ in the pathogenesis of metabolism-related diseases, atherosclerosis, fibrosis, and the delicate equilibrium between cancer progression and organ regeneration. As such, there arises a pressing need for thorough investigation of YAP/TAZ in clinical settings. In this paper, we aim to elucidate the signaling pathways that regulate YAP/TAZ and explore the mechanisms of YAP/TAZ-induce diseases and their potential therapeutic interventions. Furthermore, we summarize the current clinical studies investigating treatments targeting YAP/TAZ. We also address the limitations of existing research on YAP/TAZ and propose future directions for research. In conclusion, this review aims to provide fresh insights into the signaling mediated by YAP/TAZ and identify potential therapeutic targets to present innovative solutions to overcome the challenges associated with YAP/TAZ.

Significance of CCNs in liver regeneration

The liver has an inherent regenerative capacity via hepatocyte proliferation after mild-to-modest damage. When hepatocytes exhaust their replicative ability during chronic or severe liver damage, liver progenitor cells (LPC), also termed oval cells (OC) in rodents, are activated in the form of ductular reaction (DR) as an alternative pathway. LPC is often intimately associated with hepatic stellate cells (HSC) activation to promote liver fibrosis. The Cyr61/CTGF/Nov (CCN) protein family consists of six extracellular signaling modulators (CCN1-CCN6) with affinity to a repertoire of receptors, growth factors, and extracellular matrix proteins. Through these interactions, CCN proteins organize microenvironments and modulate cell signalings in a diverse variety of physiopathological processes. In particular, their binding to subtypes of integrin (αvβ5, αvβ3, α6β1, αvβ6, etc.) influences the motility and mobility of macrophages, hepatocytes, HSC, and LPC/OC during liver injury. This paper summarizes the current understanding of the significance of CCN genes in liver regeneration in relation to hepatocyte-driven or LPC/OC-mediated pathways. Publicly available datasets were also searched to compare dynamic levels of CCNs in developing and regenerating livers. These insights not only add to our understanding of the regenerative capability of the liver but also provide potential targets for the pharmacological management of liver repair in the clinical setting. Ccns in liver regeneration Restoring damaged or lost tissues requires robust cell growth and dynamic matrix remodeling. Ccns are matricellular proteins highly capable of influencing cell state and matrix production. Current studies have identified Ccns as active players in liver regeneration. Cell types, modes of action, and mechanisms of Ccn induction may vary depending on liver injuries. Hepatocyte proliferation is a default pathway for liver regeneration following mild-to-modest damages, working in parallel with the transient activation of stromal cells, such as macrophages and hepatic stellate cells (HSC). Liver progenitor cells (LPC), also termed oval cells (OC) in rodents, are activated in the form of ductular reaction (DR) and are associated with sustained fibrosis when hepatocytes lose their proliferative ability in severe or chronic liver damage. Ccns may facilitate both hepatocyte regeneration and LPC/OC repair via various mediators (growth factors, matrix proteins, integrins, etc.) for cell-specific and context-dependent functions.

Episodic Binge-like Ethanol Reduces Skeletal Muscle Strength Associated with Atrophy, Fibrosis, and Inflammation in Young Rats

Binge Drinking (BD) corresponds to episodes of ingestion of large amounts of ethanol in a short time, typically ≤2 h. BD occurs across all populations, but young and sports-related people are especially vulnerable. However, the short- and long-term effects of episodic BD on skeletal muscle function have been poorly explored. Young rats were randomized into two groups: control and episodic Binge-Like ethanol protocol (BEP) (ethanol 3 g/kg IP, 4 episodes of 2-days ON-2-days OFF paradigm). Muscle function was evaluated two weeks after the last BEP episode. We found that rats exposed to BEP presented decreased muscle strength and increased fatigability, compared with control animals. Furthermore, we observed that skeletal muscle from rats exposed to BEP presented muscle atrophy, evidenced by reduced fiber size and increased expression of atrophic genes. We also observed that BEP induced fibrotic and inflammation markers, accompanied by mislocalization of nNOSµ and high levels of protein nitration. Our findings suggest that episodic binge-like ethanol exposure alters contractile capacity and increases fatigue by mechanisms involving atrophy, fibrosis, and inflammation, which remain for at least two weeks after ethanol clearance. These pathological features are common to several neuromuscular diseases and might affect muscle performance and health in the long term.