The β₂-adrenergic receptor (β₂AR) is a G protein-coupled receptor (GPCR) that mediates the majority of cellular responses to external stimuli. Aberrant expression of β₂AR results in various pathophysiological disorders, including tumorigenesis, but little is known about its role in liver regeneration. This study aims to investigate the impact and the underlying mechanism of β₂AR in liver regeneration. Here, we found that β₂AR was upregulated during liver regeneration induced by 70% PH. Deletion of β₂AR in mice resulted in 62% mortality 2 days post-PH, decreased proliferative marker expression and impaired liver function throughout regeneration. Moreover, AAV8-mediated overexpression of β₂AR in hepatocytes accelerated the regeneration process and increased target gene expression. Mechanistically, β₂AR recruited G-protein-coupled receptor kinase 2 (GRK2) to the membrane and then formed a complex with c-met to transactivate c-met signaling, which triggered downstream extracellular regulated protein kinase (ERK) signaling activation and nuclear translocation. Inhibition of c-met with SU11274 or ERK with U0126 decreased β₂AR overexpression-induced hepatocyte proliferation. Our findings revealed that β₂AR might act as a critical mediator regulating liver regeneration by crosstalk with c-met and activation of ERK signaling.

Lactylation, a recently identified post-translational modification (PTM) triggered by excessive lactate accumulation, has emerged as a crucial regulator linking metabolic reprogramming to pathological processes in liver diseases. In hepatic contexts, aberrant lactylation contributes to a range of pathological processes, including inflammation, dysregulation of lipid metabolism, angiogenesis, and fibrosis. Importantly, lactylation has been shown to impact tumor growth, metastasis, and therapy resistance by modulating oncogene expression, metabolic adaptation, stemness, angiogenesis, and altering the tumor microenvironment (TME). This review synthesizes current knowledge on the biochemical mechanisms of lactylation, encompassing both enzymatic and non-enzymatic pathways, and its roles in specific liver diseases. From a therapeutic perspective, targeting lactate availability and transport, as well as the enzymes regulating lactylation, has demonstrated promise in preclinical models. Additionally, combinatorial approaches and natural compounds have shown efficacy in disrupting lactylation-driven pathways, providing insights into future research directions for hepatic diseases. Although the emerging role of lactylation is gaining attention, its spatiotemporal dynamics and potential for clinical translation are not yet well comprehended. This review aims to synthesize the multifaceted roles of lactylation, thereby bridging mechanistic insights with actionable therapeutic strategies for liver diseases.

A growing body of epidemiological evidence suggests that nonalcoholic fatty liver disease (NAFLD) is an independent risk factor for chronic kidney disease (CKD), but the regulatory mechanism linking NAFLD and CKD remains unclear. Our previous studies have shown that overexpression of PDE4D in mouse liver is sufficient for NAFLD, but little is known about its role in kidney injury. Here, liver-specific PDE4D conditional knockout (LKO) mice, adeno-associated virus 8 (AAV8)-mediated gene transfer of PDE4D and the PDE4 inhibitor roflumilast were used to assess the involvement of hepatic PDE4D in NAFLD-associated renal injury. We found that mice fed a high-fat diet (HFD) for 16 weeks developed hepatic steatosis and kidney injury, with an associated increase in hepatic PDE4D but no changes in renal PDE4D. Furthermore, liver-specific knockout of PDE4D or pharmacological inhibition of PDE4 with roflumilast ameliorated hepatic steatosis and kidney injury in HFD-fed diabetic mice. Correspondingly, overexpression of hepatic PDE4D resulted in significant renal damage. Mechanistically, highly expressed PDE4D in fatty liver promoted the production and secretion of TGF-β1 into blood, which triggered kidney injury by activating SMADs and subsequent collagen deposition. Our findings revealed PDE4D might act as a critical mediator between NAFLD and associated kidney injury and indicated PDE4 inhibitor roflumilast as a potential therapeutic strategy for NAFLD-associated CKD.

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a multifaceted systemic condition, with the mechanisms linking intrahepatic lesions to systemic complications remaining a significant enigma in the field. This review posits that extracellular vesicles (EVs) serve as pivotal mediators facilitating communication between the liver and the entire organism. Within the hepatic environment, lipotoxic hepatocyte-derived EVs modulate macrophage populations and stellate cells, thereby promoting inflammatory and fibrotic processes. Systemically, the liver engages in bidirectional communication with adipose tissue, the intestinal tract, the cardiovascular system, and the pancreas via EVs, thus orchestrating metabolic homeostasis. Furthermore, we critically evaluate non-invasive diagnostic strategies and emerging therapies, including both natural and engineered EVs, based on EV-based interventions. We highlight the substantial potential and current challenges associated with achieving precision medicine in MASLD through targeted modulation of this specific communication network.

Liver fibrosis represents a common pathway in the progression of various chronic liver diseases towards cirrhosis and liver failure. Extracellular vesicles (EVs) are membrane-enclosed particles secreted by diverse cell types, including exosomes, microvesicles, apoptotic vesicles, and the recently identified migrasomes. These vesicles can be taken up by recipient cells, thereby modulating their function through the transport of cargo molecules. EVs facilitate intercellular communication and play a significant role in the development of liver fibrosis. Moreover, the detection of EVs in various body fluids offers sensitive diagnostic tools for assessing liver fibrosis. Additionally, EVs may serve as therapeutic targets, potential therapeutic agents, and drug delivery vehicles. This article reviews recent advances in the field of EVs concerning liver fibrosis and related diseases, with a particular focus on the potential role of the newly discovered migrasomes in intracellular crosstalk within the liver.

Opioid-induced constipation (OIC) represents a prevalent adverse effect of opioid analgesics, affecting 60–90% of patients and significantly compromising quality of life. This review delineates the multifactorial pathogenesis of OIC. Peripheral μ-opioid receptor (MOR) activation suppresses enteric neuronal excitability, inhibits intestinal motility and secretion, and impairs rectoanal function. Notably, the colon appears to exhibit a distinctive lack of tolerance to opioids. Enteric glial cell activation has been implicated in neuroinflammation, while interstitial cells of Cajal show impaired pacemaker function. Central mechanisms are increasingly recognized to involve the brain–gut axis. Furthermore, opioid-induced barrier disruption, microbiota dysbiosis, and LPS/TLR4-mediated inflammation are proposed to interact and may contribute to a self-reinforcing cycle. Animal models have been instrumental in dissecting these mechanisms. However, they present limitations in reproducibility, clinical phenotype fidelity, and translational validity, particularly regarding microbiome composition and neuroimmune responses. Future research should prioritize the development of standardized, physiologically relevant animal models incorporating multi-omics approaches, and validate mechanism-based therapeutic strategies, including peripherally acting MOR antagonists and microbiota-targeted interventions, for precision management of OIC.