As the most abundant and essential structural protein in the human body, collagen is ubiquitously present in the interstitium of nearly all solid organs, playing a crucial role in maintaining the structural integrity and functional stability of human tissues and organs. Disorders associated with collagen structure and metabolisms impose a significant burden on society and healthcare systems. Post-translational modifications (PTMs) are essential steps in collagen metabolism, and recent studies have indicated that aberrant regulation of PTMs plays a pivotal role in the pathogenesis and progress of collagen-related disorders, including liver, kidney, heart, lung, and skin fibrosis, as well as keloid. This review provides a comprehensive summary of the regulatory mechanisms of both traditional and novel PTMs in collagen metabolism and collagen-related diseases. Furthermore, we summarize the drugs that modulate PTMs and their effects, with the aim of elucidating the pathophysiology of collagen-related diseases and provide new insights for their diagnosis, prevention, and treatment.

Although enteric glial cell (EGC) abnormal activation is reported to be involved in the pathogenesis of Parkinson's disease (PD), and inhibition of EGC gliosis alleviated gut and dopaminergic neuronal dysfunction was verified in our previous study, the potential role of gut microbiota on EGC function in PD still need to be addressed. In the present study, fecal microbiota transplantation revealed that EGC function was regulated by gut microbiota. By employing 16S rRNA and metabolomic analysis, we identified that 3-indolepropionic acid (IPA) was the most affected differential microbial metabolite that regulated EGC gliosis. The protective effects of IPA on PD were validated in rotenone-stimulated EGCs and rotenone (30 mg/kg i.g. for 4 weeks)-induced PD mice, as indicated by decreased inflammation, improved intestinal and brain barrier as well as dopaminergic neuronal function. Mechanistic study showed that IPA targeted pregnane X receptor (PXR) in EGCs, and inhibition of IL-13Rα1 involved cytokine–cytokine receptor interaction pathway, leading to inactivation of downstream JAK1–STAT6 pathway. Our data not only provided evidence that EGC gliosis was critical in spreading intestinal damage to brain, but also highlighted the potential role of microbial metabolite IPA in alleviating PD pathological damages through gut–brain axis.

Resistance to ferroptosis, a form of regulated cell death caused by disruptions in iron ion and intracellular redox homeostasis, is closely related to tumorigenesis and tumor drug resistance; therefore, targeting ferroptosis-related pathways has garnered attention as a potential antitumor therapeutic strategy. However, the molecular mechanisms underlying ferroptosis resistance in tumor cells remain unknown. Zinc-finger estrogen receptor interaction clone 6 (ZER6) consists of two isoforms with distinct N-termini, p52-ZER6 and p71-ZER6. ZER6 is upregulated in tumors and promotes tumorigenic potential; however, whether ZER6 is involved in tumor cell ferroptosis resistance remains unknown. Herein, we identified p52-ZER6 as a novel regulator of tumor cell ferroptosis resistance. p52-ZER6 promotes the transcriptional activity of DAZAP1, an RNA-binding protein. DAZAP1, in turn, enhances the stability of SLC7A11 mRNA by binding to its 3′-UTR region, thereby increasing SLC7A11 expression and cellular glutathione levels. This subsequently reduces lipid peroxide accumulation and enhances tumor cell ferroptosis resistance, eventually promoting tumorigenic potential. These findings reveal a new function of p52-ZER6 in regulating SLC7A11 mRNA stability via DAZAP1, ultimately leading to ferroptosis resistance and tumorigenic potential. Additionally, we also suggest targeting p52-ZER6 as a potential strategy to promote the efficacy of ferroptosis-based antitumor therapies.

Fifty whitespotted bamboo sharks (Chiloscyllium playgiosum) of both sexes were used to establish a large capacity variable domain of the new antigen receptor (VNAR) library with a total capacity of over 10⁹ colony-forming units (CFU). It was applied to screen VNARs against human serum albumin (HSA) and human transcription factor EB (TFEB), respectively. Meanwhile, VNAR libraries specific to HSA and TFEB with capacities above 10⁸ CFU were obtained following conventional immunization. These two approaches were systematically studied in terms of VNAR yield and composition. By comparing the VNAR sequences obtained from naïve and antigen-immunized libraries, we found that the complementary-determining region 3 (CDR3) of the former differs in composition from that of the latter. It shares a higher degree of homology with the naïve library. Meanwhile, the binding efficiency assessed by ELISA is also different between the naïve and antigen-immunized libraries. The binding of VNARs from the TFEB-immunized library appeared to surpass that observed with the naïve libraries, whereas the performance of VNARs from the HSA-immunized library indicated that both the immunized and naïve libraries for HSA had positive binding responses in polyclonal and monoclonal ELISA. The results are useful to develop novel diagnostic and therapeutic products based on shark VNARs.

G protein-coupled receptor kinase 2 (GRK2) participates in the phosphorylation and desensitization of G protein-coupled receptor (GPCR), impacting various biological processes such as inflammation and cell proliferation. Dysregulated expression and activity of GRK2 have been reported in multiple cells in rheumatoid arthritis (RA). However, whether and how GRK2 regulates synovial hyperplasia and fibroblast-like synoviocytes (FLSs) proliferation is poorly understood. In this study, we investigated the regulation of GRK2 and its biological function in RA. We found that GRK2 transmembrane activity was increased in FLSs of RA patients and collagen-induced arthritis (CIA) rats. Additionally, we noted a positive correlation between high GRK2 expression on the cell membrane and serological markers associated with RA and CIA. Immunoprecipitation–mass spectrometry and pull-down analyses revealed tumor necrosis factor receptor-associated factor 2 (TRAF2) as a novel substrate of GRK2. Furthermore, surface plasmon resonance (SPR) and molecular docking assays determined that the C-terminus of GRK2 binds to the C-terminus of TRAF2 at the Gln340 residue. GRK2 knockdown and the GRK2 inhibitor CP-25 attenuated synovial hyperplasia and FLS proliferation in CIA both in vitro and in vivo by decreasing GRK2 membrane expression and activity. Mechanistically, increased GRK2 transmembrane activity contributed to the recruitment of TRAF2 on the cell membrane, promoting GRK2–TRAF2 interactions that facilitate the recruitment of the E3 ubiquitin ligase TRIM47 to TRAF2. This enhanced TRAF2 Lys63 polyubiquitylation and induced nuclear factor (NF)-κB activation, leading to synovial hyperplasia and abnormal proliferation of FLSs. Our study provides a mechanistic and preclinical rationale for further evaluation of GRK2 as a therapeutic target for RA.

Human respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections in infants and young children, as well as an important cause of respiratory tract infections in immunocompromised patients and the elderly, which poses a significant economic and social burden worldwide. In recent years, substantial progress has been made in understanding the structure and function of RSV proteins and the interactions between RSV with host factors which is helpful to the discovery of new therapeutic targets and the development of novel interventions. Although two vaccines and two monoclonal antibodies for RSV prevention have been approved, the antiviral treatment remains an unmet clinical need. In this review, we summarize the structure, protein functional properties, and pathological mechanisms of RSV and the current status of RSV drug development. In addition, remaining challenges and innovative ideas for RSV prevention and treatment have also been highlighted.

Cancer immunotherapy has emerged as a promising strategy. However, low response rates and immune-related side effects have plagued immunotherapy. Metallic nanoparticles, utilizing metals as their framework, are gaining prominence in cancer immunotherapy. Metal ions have shown the ability to modulate immune status by activating the cGAS–STING pathway and inducing immunogenic cell death (ICD), thereby enabling multidimensional activation of immunotherapy. Metallic nanoparticles offer significant advantages in cancer immunotherapy, leading to their increasing use in enhancing therapeutic outcomes. In view of the ever-increasing research on metallic nanoparticles, this review presents the construction, characterization, and enhanced cancer immunotherapeutic effects of different types of metal nanosystems from the perspective of the immunoregulatory mechanisms of metal ions. We delve into the current limitations and future directions of metallic nanoparticles in this rapidly evolving field. To the best of our knowledge, this review offers the most up-to-date and systematic analysis of metallic nanoparticles in immunotherapeutic applications. It is anticipated that this review of metallic nanoparticles will inspire a more refined and intelligent design of metallic nanoparticles for future research, paving the way for advancing their clinical applications.

The size of nanodrugs plays a crucial role in shaping their chemical and physical characteristics, consequently influencing their therapeutic and diagnostic interactions within biological systems. The optimal size of nanomedicines, whether small or large, offers distinct advantages in disease treatment, creating a dilemma in the selection process. Addressing this challenge, size-transformable nanodrugs have surfaced as a promising solution, as they can be tailored to entail the benefits associated with both small and large nanoparticles. In this review, various strategies are summarized for constructing size-transformable nanosystems with a focus on nanotherapeutic applications in the field of biomedicine. Particularly we highlight recent research developments in cancer therapy. This review aims to inspire researchers to further develop various toolboxes for fabricating size-transformable nanomedicines for improved intervention against diverse human diseases.

Increasing evidence shows that the early lesions of Parkinson's disease (PD) originate from gut, and correction of microbiota dysbiosis is a promising therapy for PD. FLZ is a neuroprotective agent on PD, which has been validated capable of alleviating microbiota dysbiosis in PD mice. However, the detailed mechanisms still need elucidated. Through metabolomics and 16S rRNA analysis, we identified glycoursodeoxycholic acid (GUDCA) was the most affected differential microbial metabolite by FLZ treatment, which was specially and negatively regulated by Clostridium innocuum, a differential microbiota with the strongest correlation to GUDCA production, through inhibiting bile salt hydrolase (BSH) enzyme. The protection of GUDCA on colon and brain were also clarified in PD models, showing that it could activate Nrf2 pathway, further validating that FLZ protected dopaminergic neurons through promoting GUDCA production. Our study uncovered that FLZ improved PD through microbiota–gut–brain axis, and also gave insights into modulation of microbial metabolites may serve as an important strategy for treating PD.

Human NAD(P)H: quinone oxidoreductase 1 (NQO1) is a flavoenzyme expressed at high levels in multiple solid tumors, making it an attractive target for anticancer drugs. Bioactivatable drugs targeting NQO1, such as β-lapachone (β-lap), are currently in clinical trials for the treatment of cancer. β-Lap selectively kills NQO1-positive (NQO1⁺) cancer cells by inducing reactive oxygen species (ROS) via catalytic activation of NQO1. In this study, we demonstrated that cryptotanshinone (CTS), a naturally occurring compound, induces NQO1-dependent necrosis without affecting NQO1 activity. CTS selectively kills NQO1⁺ cancer cells by inducing NQO1-dependent necrosis. Interestingly, CTS directly binds to NQO1 but does not activate its catalytic activity. In addition, CTS enables activation of JNK1/2 and PARP, accumulation of iron and Ca²⁺, and depletion of ATP and NAD⁺. Furthermore, CTS selectively suppressed tumor growth in the NQO1⁺ xenograft models, which was reversed by NQO1 inhibitor and NQO1 shRNA. In conclusion, CTS induces NQO1-dependent necrosis via the JNK1/2/iron/PARP/NAD⁺/Ca²⁺ signaling pathway. This study demonstrates the non-enzymatic function of NQO1 in inducing cell death and provides new avenues for the design and development of NQO1-targeted anticancer drugs.