Objective: Diabetic skin ulcers are a common and intractable complication of diabetes. This study intends to investigate the therapeutic effects of a plant-derived carboxyethyl chitosan hydrogel on diabetic skin ulcers.Methods: A plant-derived carboxyethyl chitosan hyaluronic acid-carboxyethyl chitosan (HA-CECS) hydrogel was prepared using the chemical cross-linking method to characterize its structure and biocompatibility. Eight- to ten-week-old male C57BL/6J mice were randomly divided into three groups: a model control group (Control), a gel experimental group (HA-CECS), and a commercial gel control group (Commercial control). A diabetic mouse model was constructed using streptozotocin and then a whole-layer skin injury model was constructed using the diabetic mouse model. Equal volumes of HA-CECS aqueous gel and commercial gel were applied to the trauma in the HA-CECS and Commercial control groups, respectively, and equal volumes of saline were applied to the Control group. The wound was covered and fixed with a transparent, aseptic patch, and the medication was changed at intervals of 2 to 3 days. The animals were anesthetized and euthanized on the 7th and 14th day, respectively. Wound tissues were collected and examined for pathological changes, the level of neovascularization, and macrophage phenotype. Results: (1) The results of the H nuclear magnetic resonance spectra and Fourier infrared scanning analyses confirmed that the CECS was successfully prepared. The HA-CECS hydrogel exhibited no obvious toxic effects on fibroblasts and reduced the lipopolysaccharide-induced polarization of CD80+ pro-inflammatory macrophages. (2) The results of the animal experiments showed that, compared with the Control group, the wound healing rate, neo-epidermal thickness, collagen deposition, and CD31 expression level were significantly higher in the HA-CECS group mice (P< 0.001). The number of CD68+iNOS+ macrophages in the skin tissue decreased significantly (P< 0.01), while the number of CD68+CD206+ macrophages increased significantly (P< 0.01). Compared with the Commercial control group, the HA-CECS group showed a significant increase in wound healing rate (P< 0.05), decreased neoplastic epidermal thickness and collagen deposition levels (P< 0.05), significantly enhanced CD31 expression levels in skin tissue (P< 0.001), and significantly increased number of CD68+CD206+ macrophages in skin tissue (P<0.01).Conclusion: HA-CECS hydrogel effectively promotes the repair of skin injuries in diabetic mice.
Objective: This research employed the rhamnose (Rha) modification approach based on the strategy of targeting endogenous antibody-mediated antigen-presenting cells (APCs) to enhance the immunological efficacy of a Staphylococcus aureus (S. aureus) vaccine containing α-hemolysin (Hla), with particular focus on improving APC targeting and toxin-neutralizing activity. Methods: Both Hla and wild-type Hla (WT Hla) were expressed and purified. Sortase A (SrtA)-mediated ligation was employed to site-specifically conjugate multivalent Rha to the C-terminus of Hla, generating the corresponding conjugates. These conjugates were characterized using SDS-PAGE and Western blot. THP-1-differentiated macrophages were utilized to evaluate the capacity of the conjugates to target APCs via flow cytometry. Mice were immunized with the conjugates, and their serum antibody titers and subtypes were measured using ELISA. Additionally, toxin neutralization assays were performed to evaluate the ability of immune sera to neutralize purified WT Hla and the culture supernatant of S. aureus ATCC 29213 isolates. Results: Five conjugates (H1-H5) were successfully synthesized, with production yields ranging from 63% to 91%. Flow cytometry revealed that H3 conjugate exhibited the strongest capacity to target APCs, with a mean fluorescence intensity (MFI) that was 61.4 times higher than that of the control group. Immunization and neutralization experiments in mice demonstrated that the H2 conjugate induced the highest anti-Hla IgG antibody titers in pre-immunized mice. with the highest NT50 value against wild-type (WT) Hla. This value was 1.47-fold higher than that of the Hla-alone immunization group. Meanwhile, the serum of mice immunized with the H3 conjugate showed the highest NT50 value against the culture supernatant of S. aureus ATCC 29213 culture supernatant, which was 3.4 times higher than that of the Hla-alone group. Conclusion: Rha modification represents an effective strategy for enhancing the APC targeting capacity and neutralizing activity of Hla-based S. aureus vaccines, thereby improving their immunological efficacy.
Parkinson’s disease (PD) is a common, age-related, neurodegenerative disorder that affects the central nervous system. Catechol-isoquinolines (CTIQs) are known to induce the death of dopaminergic neurons and are recognized as potential endogenous neurotoxins implicated in PD. Salsolinol synthase, a key enzyme responsible for synthesizing salsolinol (Sal), a representative CTIQ, is hypothesized to play a pivotal role in PD pathogenesis. Previous studies have identified its high amino acid sequence homology with ubiquitin and classified it as a member of the ubiquitin-like protein (UBL) family. This study further reveals that salsolinol synthase and ubiquitin have conserved spatial structures and catalytic functions, as well as notable divergences. Specifically, salsolinol synthase exhibits an optimal temperature closely aligned with the body’s physiological temperature. It also demonstrates a pH-dependent enzymatic activity mechanism: it exhibits high catalytic activity under normal physiological pH conditions, but is significantly inhibited under acidic pH conditions that mimic cellular damage. These findings broaden our understanding of the functions of salsolinol synthase and UBL proteins, providing critical theoretical foundations for elucidating PD mechanisms and developing targeted therapeutic strategies.
The presence of phage contamination during the industrial fermentation of Bacillus subtilis poses a significant challenge to the industry. In this study, a lytic phage, PJNB028, was isolated using Bacillus subtilis K28, a strain commonly used in feed production, as the host. The biological characteristics, complete genome annotation, phylogenetic analysis, and host resistance screening of PJNB028 were systematically investigated. PJNB028 could produce circular, transparent plaques with clear edges and halos on the host bacterial lawn. The phage had a linear, double-stranded DNA genome that was 162 308 base pairs (bp) long, had a G+C content of 34%, and encoded 237 open reading frames (ORFs). It belongs to the order Caudoviricetes. The optimal multiplicity of infection (MOI) was found to be 1. PJNB028 exhibited acid tolerance (pH 3-11), though it was less resistant to alkaline conditions. It maintained relatively stable UV tolerance. The latent period of PJNB028 was 10 min, with a burst period of 70 min and a burst size of 291 PFU/cell. The phage titer decreased significantly after one hour of treatment at 70-80℃, while it demonstrated effective antibacterial activity against Bacillus cells after 8 h at 37℃. PJNB028 was able to lyse 50% (n=20) of Bacillus species such as B. mojave and B. subtilis. Three resistant strains were isolated through the co-cultivation of a phage and its host bacteria. During fermentation, some of these resistant strains exhibited significantly higher titers and α-amylase activities compared to the original host strain. According to its biological properties and genomic analysis, PJNB028 can be prevented and controlled using resistant strains or a combination of hot alkaline solutions, autoclaving, and ultraviolet disinfection. This study provides a reliable research material for preventing and controlling Bacillus phage contamination in the future.
Halogenated compounds are highly valuable for use in the pharmaceutical and agricultural industries. In particular, alkaloids and indoles derived from halotryptophan precursors have been developed into innovative pesticides and antibiotics. Halogen-based, catalyzed halogenation reactions are an efficient and environmentally friendly approach to synthesizing halotryptophan. In this study, we successfully produced halotryptophan by expressing a flavin-dependent halogenase from Streptomyces sp. and a flavin reductase in Escherichia coli. A series of mono- and polyhalogenated tryptophan products were successfully synthesized by exogenous addition of various halogen ions (Cl-, Br-). Additionally, we explored the substrate preferences of halogenases by introducing different enzyme systems and clarified the halogenation sequence of dichloro-substituted tryptophan through molecular dynamics simulations. Meanwhile, the fermentation conditions were optimized to further increase the yield of 6-chlorotryptophan, resulting in a final titer of 3.18 mg/L. This study successfully produced a series of mono- and polyhalogen-substituted tryptophan products via whole-cell catalysis, providing a technological foundation for the green manufacturing and application of subsequent functional derivatives.
MORF4L1 is a core regulator of chromatin remodeling and genomic stability that is dynamically regulated by the ubiquitin-proteasome system. However, its specific E3 ubiquitin ligase remains incompletely understood. By integrating APEX2 proximity labeling technology with quantitative proteomics, the interaction network of MORF4L1 was systematically analyzed, leading to the identification of a novel E3 ligase. We screened 112 high-confidence interacting proteins through the construction of HEK-293T cell lines stably expressing Flag-APEX2-MORF4L1 and treatment with the NEDD8-activating enzyme (NAE) inhibitor MLN4924. GO enrichment analysis revealed that the differential proteins were significantly enriched in pathways related to DNA methylation-dependent heterochromatin formation and the regulation of chromosome segregation. A broad association between MORF4L1 and mRNA metabolism-related proteins has been uncovered for the first time, suggesting its novel function as a “chromatin-RNA interface” regulatory factor. Further validation revealed that DCAF15, the substrate recognition subunit of the CRL4 ubiquitin ligase complex, binds directly to and mediates the polyubiquitination and degradation of MORF4L1. Co-immunoprecipitation (Co-IP) and TUBE pull-down experiments confirmed that DCAF15 regulates the protein turnover of MORF4L1 through dynamic interactions. This pathway may operate independently of the previously reported SCFFBXL18 pathway to collectively maintain its functional homeostasis. The APEX2 technology, with its live-cell in situ labeling and minute-level dynamic capture capabilities, has been demonstrated to effectively resolve low-abundance transient interactions, such as E3 enzyme-substrate binding events, providing a methodological paradigm for studying protein ubiquitination regulation. The discovery of the DCAF15-MORF4L1 regulatory axis expands our understanding of the regulatory mechanisms of MORF4L1 in cancer and metabolic diseases. It also offers new strategies for targeted intervention in its protein stability, such as using DCAF15 molecular glue drugs.
Leukemia inhibitory factor (LIF) is overexpressed in various cancers, including head and neck cancer, melanoma, renal cancer, prostate cancer, pancreatic cancer, and endometrial cancer. This cytokine plays a crucial role in promoting tumor cell proliferation, migration, immune evasion and drug resistance. These functions make it a key factor in tumorigenesis and progression. Therefore, targeting the LIF signaling pathway has emerged as a novel cancer therapy strategy. This review provides a structure-based overview of the structural features of LIF and its molecular interactions with receptors, LIFR and glycoprotein 130 (gp130). Additionally, we explore the molecular mechanism of the LIF-neutralizing antibody MSC-1 and analyze the potential molecular interactions between the LIFR-targeting small molecule inhibitor EC359 and LIFR. These detailed analyses of molecular interactions provide important theoretical insights for designing and optimizing drugs that target the LIF signaling pathway.
Objective: A systematic review of the literature on treating respiratory diseases through pulmonary inhalation of exosomes was conducted to better understand the existing research and provide references. Methods: The relevant literature on exosomes in respiratory diseases over the past decade was searched and classified using the keywords “pulmonary inhalation”, “exosomes” or “respiratory diseases” through platforms such as China National Knowledge Infrastructure (CNKI) and PubMed. Results: Exosomes from different biological sources, such as mesenchymal stem cells, immune cells, and plant-derived exosomes, can be targeted and accumulated in lung tissue via inhalation (typically nebulized inhalation) or airway administration (e.g., intratracheal instillation) routes. They can synergistically improve the pathological state of the lungs through multiple mechanisms, effectively treating various respiratory diseases. These exosomes, by virtue of the specific proteins or nucleic acids carried on their surfaces, act precisely on the diseased cells in the lungs. When delivering therapeutic drugs or genes, they can not only enhance the therapeutic effect but also reduce systemic adverse reactions. Exosomes primarily reduce pulmonary inflammation and encourage the restoration of damaged lung tissue by regulating macrophage polarization and modulating multiple signaling pathways, including various NF-κB and PI3K/Akt. Conclusion: Although exosome inhalation therapy shows broad application prospects for respiratory-related diseases, there is a lack of clinical research, and further studies are warranted.
In vivo directed evolution technology has been extensively utilized in genetic engineering to provide robust technical support for protein and enzyme engineering. The target gene or the entire genome is mutated in vivo. Then, a mutant library is generated by applying specific selective pressure to obtain mutants with the desired phenotypes. This technique has been successfully applied to a variety of bacteria and fungi. Increasing the mutation rate has emerged as a pivotal step for the success of in vivo directed evolution. Methods for enhancing the in vivo mutation rate and expanding the mutation window have continuously evolved over the years, thereby laying a solid foundation for the development of in vivo directed evolution. Additionally, expanding the types of mutations and broadening the target range have become significant areas of research. The principles and applications of various in vivo directed evolution techniques, such as phage-assisted directed evolution, deaminase-mediated base editing, and orthogonal replication mutation, have been reviewed. The challenges and prospects of in vivo directed evolution techniques were also discussed.
Aromatic nitro compounds, as important intermediates for organic synthesis, are widely used in the fields of medicine, pesticides and materials. Frequently, traditional chemical nitration methods are plagued by harsh conditions, poor selectivity and environmental pollution. In recent years, bioenzymatic nitration has become a popular research topic in green chemical synthesis due to its advantages of high efficiency, specificity, and environmental friendliness. This review summarizes the recent progress in nitration reactions using an enzymatic method, focusing on the application of biocatalysts, such as N-oxygenases, peroxidases, cytochrome P450 enzymes, and halohydrin dehalogenases in nitration reactions. The review also discusses the reaction mechanisms, advantages and disadvantages, and scope of application of different enzyme-catalyzed systems in detail. In the future, artificial intelligence is expected to accelerate the application of nitroxide enzymes in the synthesis of nitro drugs and functional materials.
Polyethylene terephthalate (PET) is a plastic that is widely used in our daily lives. Because of its stable structure, it is very difficult to degrade naturally, posing a serious threat to the ecological environment and human health. Therefore, the degradation and recycling of PET plastics has become a popular research topic. Compared with traditional physical and chemical degradation methods, the biological degradation method has the advantages of ecological friendliness and sustainability. It is a method with great potential. However, the further application of natural PET hydrolase is limited due to its low activity and stability. To this end, researchers developed and optimized a variety of enzymic modification methods and enzymic assembly strategies for PET hydrolase, improving its catalytic performance and stability. This review summarizes the research on modifying and assembling PET hydrolases, and discusses the main limitations and solutions for future industrial applications of PET biodegradation to provide insight into further developments.
Cellulose is one of the most abundant renewable resources on earth, and its efficient and sustainable utilization has become a key focus of current research. Enzymatic degradation of cellulose for clean energy production represents a green, highly efficient conversion approach. Cellulose-degrading enzymes form complex enzyme systems that typically consist of endoglucanase, exoglucanase, and β-glucosidase. This article systematically classifies and reviews modification strategies for these three cellulose-degrading enzymes, organized by distinct engineering approaches. Because most cellulose-degrading enzymes suffer from suboptimal thermal stability and catalytic efficiency, genetic engineering and protein engineering techniques have been employed to enhance these critical properties. Such improvements are significantly important for industrial applications and open up new opportunities for using cellulose-degrading enzymes. These advancements offer valuable insights for optimizing bioenergy production processes and promoting sustainable resource utilization.
