Ribosomally synthesized and post-translationally modified peptides (RiPPs) constitute a vast and diverse family of bioactive peptides. These peptides, synthesized by ribosomes and subsequently modified by various tailoring enzymes, possess a wide chemical space. Among these modifications, radical S-adenosylmethionine (rSAM) enzymes employ unique radical chemistry to introduce a variety of novel peptide structures, which are crucial for their activity. This review examines the major types of modifications in RiPPs catalyzed by rSAM enzymes, incorporating recent advancements in protein structure analysis techniques and computational methods. Additionally, it elucidates the diverse catalytic mechanisms and substrate selectivity of these enzymes through an analysis of the latest crystal structures.
Protein Processing, Post-Translational ; S-Adenosylmethionine/chemistry* ; Ribosomes/metabolism* ; Peptides/metabolism* ; Biological Products/metabolism* ; Humans

Triggering receptor expressed on myeloid cells 2 (TREM2)-mediated microglial phagocytosis is an energy-intensive process that plays a crucial role in amyloid beta (Aβ) clearance in Alzheimer's disease (AD). Energy metabolic reprogramming (EMR) in microglia induced by TREM2 presents therapeutic targets for cognitive impairment in AD. Jiawei Xionggui Decoction (JWXG) has demonstrated effectiveness in enhancing energy supply, protecting microglia, and mitigating cognitive impairment in APP/PS1 mice. However, the mechanism by which JWXG enhances Aβ phagocytosis through TREM2-mediated EMR in microglia remains unclear. This study investigates how JWXG facilitates microglial phagocytosis and alleviates cognitive deficits in AD through TREM2-mediated EMR. Microglial phagocytosis was evaluated through immunofluorescence staining in vitro and in vivo. The EMR level of microglia was assessed using high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) kits. The TREM2/protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/hypoxia-inducible factor-1α (HIF-1α) signaling pathway was analyzed using Western blotting in BV₂ cells. TREM2^-/- BV₂ cells were utilized for reverse validation experiments. The Aβ burden, neuropathological features, and cognitive ability in APP/PS1 mice were evaluated using ELISA kits, immunohistochemistry (IHC), and the Morris water maze (MWM) test. JWXG enhanced both the phagocytosis of EMR disorder-BV₂ cells (EMRD-BV₂) and increased EMR levels. Notably, these effects were significantly reversed in TREM2^-/- BV₂ cells. JWXG elevated TREM2 expression, adenosine triphosphate (ATP) levels, and microglial phagocytosis in APP/PS1 mice. Additionally, JWXG reduced Aβ-burden, neuropathological lesions, and cognitive deficits in APP/PS1 mice. In conclusion, JWXG promoted TREM2-induced EMR and enhanced microglial phagocytosis, thereby reducing Aβ deposition, improving neuropathological lesions, and alleviating cognitive deficits.
Drugs, Chinese Herbal/pharmacology* ; Microglia/drug effects* ; Phagocytosis ; Cognitive Dysfunction/drug therapy* ; Metabolic Reprogramming ; Animals ; Mice ; Cell Line ; Receptors, Immunologic/metabolism* ; Membrane Glycoproteins/metabolism* ; Signal Transduction ; Amyloid beta-Peptides/metabolism* ; Energy Metabolism

OBJECTIVES: This study investigated the effects of a polycaprolactone (PCL)-polyethylene glycol (PEG) scaffold incorporated with concentrated growth factor (CGF) on the adhesion, proliferation, and osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). METHODS: The PCL-PEG-CGF composite scaffold was fabricated using an immersion and freeze-drying technique. Its microstructure, mechanical properties, and biocompatibility were systematically characterized. The hPDLSCs were isolated through enzymatic digestion, and the hPDLSCs were identified through flow cytometry. Third-passage hPDLSCs were seeded onto the composite scaffolds, and their adhesion, proliferation and osteogenic differentiation were assessed using CCK-8 assays, 4',6-diamidino-2-phenylindole (DAPI) staining, alkaline phosphatase (ALP) staining, alizarin red staining, and Western blot analysis of osteogenesis-related proteins [Runt-related transcription factor 2 (Runx2), ALP, and morphogenetic protein 2 (BMP2)]. RESULTS: Scanning electron microscopy revealed that the PCL-PEG-CGF composite scaffold exhibited a honeycomb-like structure with heterogeneous pore sizes. The composite scaffold exhibited excellent hydrophilicity, as evidenced by a contact angle (θ) approaching 0° within 6 s. Its elastic modulus was measured at (4.590 0±0.149 3) MPa, with comparable hydrophilicity, fracture tensile strength, and fracture elongation to PCL-PEG scaffold. The hPDLSCs exhibited significantly improved adhesion to the PCL-PEG-CGF composite scaffold compared with the PCL-PEG scaffold (P<0.01). Additionally, cell proliferation was markedly improved in all the experimental groups on days 3, 5, and 7 (P<0.01), and statistically significant differences were found between the PCL-PEG-CGF group and other groups (P<0.01). The PCL-PEG-CGF group showed significantly elevated ALP activity (P<0.05), increased mineralization nodule formation, and upregulated expression of osteogenic-related proteins (Runx2, BMP2 and ALP; P<0.05). CONCLUSIONS The PCL-PEG-CGF composite scaffold exhibited excellent mechanical properties and biocompatibility, enhancing the adhesion and proliferation of hPDLSCs and promoting their osteogenic differentiation by upregulating osteogenic-related proteins.
Humans ; Polyesters/chemistry* ; Periodontal Ligament/cytology* ; Polyethylene Glycols/chemistry* ; Stem Cells/cytology* ; Tissue Scaffolds ; Cell Proliferation ; Osteogenesis ; Cell Differentiation ; Cell Adhesion ; Bone Morphogenetic Protein 2/metabolism* ; Cells, Cultured ; Alkaline Phosphatase/metabolism* ; Core Binding Factor Alpha 1 Subunit/metabolism* ; Intercellular Signaling Peptides and Proteins/pharmacology* ; Tissue Engineering/methods*

Bacillus is a class of spore-producing Gram-positive bacteria that produce a variety of antimicrobial substances with different structures and functions. The application of the antimicrobial substances produced by Bacillus can effectively inhibit the activity of harmful bacteria and fungi and promote the sustainable development of green agriculture. The antimicrobial substances produced by Bacillus mainly include proteins, lipopeptides, polyketones, and polypeptides. This paper reviews the synthesis gene clusters, synthesis pathways, structures, and mechanisms of various antimicrobial substances produced by Bacillus and discusses the challenges in the industrial application of these antimicrobial substances. Furthermore, this paper clarifies the future research and development focuses and prospects the application prospects, and provides comprehensive theoretical support for the in-depth research and wide application of the antimicrobial substances produced by Bacillus.
Bacillus/genetics* ; Anti-Infective Agents/metabolism* ; Bacterial Proteins/genetics* ; Antimicrobial Peptides/biosynthesis* ; Lipopeptides/biosynthesis*

OBJECTIVE: To investigate the mechanism of electroacupuncture (EA) in treating diabetic gastroparesis (DGP) by inhibiting the activation of Nod-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome and pyroptosis mediated via NLRP3/cysteinyl aspartate specific proteinase-1 (caspase-1)/gasdermin D (GSDMD) signaling pathway. METHODS: Forty Sprague-Dawley rats were randomly divided into 4 groups including the control, DGP model, EA, and MCC950 groups. The DGP model was established by a one-time high-dose intraperitoneal injection of 2% streptozotocin and a high-glucose and high-fat diet for 8 weeks. EA intervention was conducted at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) with sparse-dense wave for 15 min, and was administered for 3 courses of 5 days. After intervention, the blood glucose, urine glucose, gastric emptying, and intestinal propulsive rate were observed. Besides, HE staining was used to observe histopathological changes in gastric antrum tissues, and TUNEL staining was utilized to detect DNA damage. Protein expression levels of NLRP3, apoptosis-associated speck-like protein containing CARD (ASC), pro-caspase-1, caspase-1 and GSDMD were measured by Western blot. Immunofluorescence staining was employed to assess the activity of GSDMD-N. Lactate dehydrogenase (LDH) levels were detected by using a biochemical kit. RESULTS: DGP rats showed persistent hyperglycemia and a significant decrease in gastrointestinal motility (P<0.05 or P<0.01), accompanied by pathological damage in their gastric antrum tissues. Cellular DNA was obviously damaged, and the expressions of NLRP3, ASC, pro-caspase-1, caspase-1 and GSDMD proteins were significantly elevated, along with enhanced fluorescence signals of GSDMD-N and increased LDH release (P<0.01). EA mitigated hyperglycemia, improved gastrointestinal motility in DGP rats and alleviated their pathological injury (P<0.05). Furthermore, EA reduced cellular DNA damage, lowered the protein levels of NLRP3, ASC, pro-caspase-1, caspase-1 and GSDMD, suppressed GSDMD-N activity, and decreased LDH release (P<0.05 or P<0.01), demonstrating effects comparable to MCC950. CONCLUSION EA promotes gastrointestinal motility and repairs the pathological damage in DGP rats, and its mechanism may be related to the inhibition of NLRP3 inflammasome and pyroptosis mediated by NLRP3/caspase-1/GSDMD pathway.
Animals ; Electroacupuncture ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Pyroptosis ; Rats, Sprague-Dawley ; Caspase 1/metabolism* ; Gastroparesis/physiopathology* ; Signal Transduction ; Male ; Diabetes Mellitus, Experimental/physiopathology* ; Phosphate-Binding Proteins/metabolism* ; Gastrointestinal Motility ; Rats ; Intracellular Signaling Peptides and Proteins/metabolism* ; Diabetes Complications/physiopathology* ; Gasdermins

OBJECTIVE: To investigate the Wnt signaling pathway and miRNAs mechanism of extracts of Plastrum Testudinis (PT) in the treatment of osteoporosis (OP). METHODS: Thirty female Sprague Dawley rats were randomly divided into 5 groups by random number table method, including sham group, ovariectomized group (OVX), ovariectomized groups treated with high-, medium-, and low-dose PT (160, 80, 40 mg/kg per day, respectively), with 6 rats in each group. Except for the sham group, the other rats underwent bilateral ovariectomy to simulate OP and received PT by oral gavage for 10 consecutive weeks. After treatment, bone mineral density was measured by dual-energy X-ray absorptiometry; bone microstructure was analyzed by micro-computed tomography and hematoxylin and eosin staining; and the expressions of osteogenic differentiation-related factors were detected by immunochemistry, Western blot, and quantitative polymerase chain reaction. In addition, Dickkopf-1 (Dkk-1) was used to inhibit the Wnt signaling pathway in bone marrow mesenchymal stem cells (BMSCs) and miRNA overexpression was used to evaluate the effect of miR-214 on the osteogenic differentiation of BMSCs. Subsequently, PT extract was used to rescue the effects of Dkk-1 and miR-214, and its impacts on the osteogenic differentiation-related factors of BMSCs were evaluated. RESULTS: PT-M and PT-L significantly reduced the weight gain in OVX rats (P<0.05). PT also regulated the bone mass and bone microarchitecture of the femur in OVX rats, and increased the expressions of bone formation-related factors including alkaline phosphatase, bone morphogenetic protein type 2, collagen type I alpha 1, and runt-related transcription factor 2 when compared with the OVX group (P<0.05 or P<0.01). Meanwhile, different doses of PT significantly rescued the inhibition of Wnt signaling pathway-related factors in OVX rats, and increased the mRNA or protein expressions of Wnt3a, β-catenin, glycogen synthase kinase-3β, and low-density lipoprotein receptor-related protein 5 (P<0.05 or P<0.01). PT stimulated the osteogenic differentiation of BMSCs inhibited by Dkk-1 and activated the Wnt signaling pathway. In addition, the expression of miR-214 was decreased in OVX rats (P<0.01), and it was negatively correlated with the osteogenic differentiation of BMSCs (P<0.01). MiR-214 mimic inhibited Wnt signaling pathway in BMSCs (P<0.05 or P<0.01). Conversely, PT effectively counteracted the effect of miR-214 mimic, thereby activating the Wnt signaling pathway and stimulating osteogenic differentiation in BMSCs (P<0.05 or P<0.01). CONCLUSION PT stimulates bone formation in OVX rats through β-catenin-mediated Wnt signaling pathway, which may be related to inhibiting miR-214 in BMSCs.
Animals ; MicroRNAs/genetics* ; Female ; Rats, Sprague-Dawley ; Wnt Signaling Pathway/genetics* ; Osteogenesis/genetics* ; Mesenchymal Stem Cells/cytology* ; Cell Differentiation/drug effects* ; Bone Density/drug effects* ; Ovariectomy ; Osteoporosis/drug therapy* ; beta Catenin/metabolism* ; Rats ; Intercellular Signaling Peptides and Proteins/metabolism* ; Drugs, Chinese Herbal/pharmacology*

OBJECTIVE: To explore the mechanism of Dihuang Yinzi (DHYZ) in the treatment of Alzheimer's disease (AD) by integrating metabolomics and experimental verification. METHODS: Forty-eight male APP/PS1 mice were divided into model, high- (DHYZ-H), medium- (DHYZ-M), and low-dose DHYZ (DHYZ-L) groups (12 mice per group) according to a random number table. Mice in DHYZ groups were gavaged with DHYZ 6.34, 12.68, and 25.35 g/(kg·d), respectively. Twelve C57BL/6 mice were gavaged with distilled water as the blank group. Metabolomics was used to analyze differential metabolites in the brains of mice. Morris water maze test was used to detect the memory abilities of mice. The hematoxylin-eosin staining and transmission electron microscopy were used to observe the general morphology and ultrastructure of neurons. The enzyme-linked immunosorbent assay was used to detect the levels of superoxide dismutase (SOD), reactive oxygen species (ROS), and amyloid β -protein 1-42 (A β_1-42). The real-time quantitative polymerase chain reaction was used to detect the mRNA expressions of density-regulated protein 1 (DRP1), fission 1 (FIS1), mitofusin-1 (MFN1), and optic atrophy protein 1 (OPA1). Western blot was used to detect the protein expressions of cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), cAMP response binding protein (CREB), brain-derived neurotrophic factor (BDNF), synapsin 1 (SYN1), synaptophysin (SYP), and postsynaptic density protein 95 (PSD95). RESULTS: A total of 82 differential metabolites were identified in the brains of APP/PS1 mice, among which 7 differential metabolites could be regulated by DHYZ. After DHYZ intervention, the memory abilities of mice significantly increased (P<0.05 or P<0.01), the number of synapses and neurons in the hippocampus increased, and the mitochondrial morphology and structure were relatively intact. The DHYZ groups exhibited a significant reduction in hippocampal ROS and A β_1-42 levels, along with a significant elevation in SOD level (P<0.05 or P<0.01). The mRNA expressions of DRP1 and FIS1 were reduced, while the mRNA expressions of MFN1 and OPA1 were increased after DHYZ treatment (P<0.05 or P<0.01). The cAMP/PKA/CREB-BDNF pathway was activated, and the expressions of SYN1, SYP and PSD95 proteins were significantly increased in the DHYZ-H group (P<0.05 or P<0.01). CONCLUSIONS DHYZ could improve mitochondrial dynamics and synaptic plasticity in APP/PS1 mice, inhibit oxidative stress, and thereby enhancing learning and memory abilities in APP/PS1 mice. Its mechanism might be related to activation of the cAMP/PKA/CREB-BDNF signaling pathway.
Animals ; Brain-Derived Neurotrophic Factor/metabolism* ; Male ; Cyclic AMP Response Element-Binding Protein/metabolism* ; Brain/drug effects* ; Metabolomics ; Mice, Inbred C57BL ; Neuronal Plasticity/drug effects* ; Drugs, Chinese Herbal/therapeutic use* ; Cyclic AMP-Dependent Protein Kinases/metabolism* ; Cyclic AMP/metabolism* ; Reactive Oxygen Species/metabolism* ; Amyloid beta-Protein Precursor/metabolism* ; Mice, Transgenic ; Mice ; Amyloid beta-Peptides/metabolism* ; Signal Transduction/drug effects* ; Alzheimer Disease/drug therapy* ; Superoxide Dismutase/metabolism*

OBJECTIVE: To explore the mechanism of crocin, a major active component of Crocus sativus (Zanghonghua), in regulating amyloid beta (Aβ) generation, endoplasmic reticulum (ER) stress, and autophagy in neuronal cells, with potential therapeutic applications in Alzheimer's disease (AD). METHODS: Mouse neuroblastoma Neuron2a (N2a) cells stably transfected with the human amyloid precursor protein (APP) Swedish mutant was used as a cellular model for AD (N2a/APP). Control cells were vector transfected (N2a/vector). The effects of 3 different doses of crocin on reactive oxygen species (ROS) generation, cytosolic calcium, and apoptosis were evaluated by flow cytometry. Aβ levels were determined by enzyme-linked immunosorbent assay. APP processing and ER stress proteins expressions were determined by Western blot. Autophagosome formation was evaluated by autophagy detection kit and confocal microscope. RESULTS: Crocin inhibited APP expression in N2a/APP cells and promoted α-cleavage of APP processing, while modestly reduced beta-secretase 1 (BACE1) and presenilin 1 (PS1, P<0.05 or P<0.01). ER stress markers, including the binding immunoglobulin protein/78-kD glucose-regulated protein (Bip/GRP78) and C/EBP homologous protein (CHOP), were elevated in N2a/APP cells compared to N2a/vector cells (P<0.05). Crocin could effectively reduce the levels of ER stress (P<0.05 or P<0.01). In addition, crocin enhanced autophagy by promoting formation of autophagosome (P<0.05 or P<0.01). CONCLUSION Crocin significantly inhibited Aβ generation by promoting α-cleavage of APP processing, inhibiting ER stress-associated unfolded protein response, and regulating autophagy.
Endoplasmic Reticulum Stress/drug effects* ; Autophagy/drug effects* ; Animals ; Endoplasmic Reticulum Chaperone BiP ; Mice ; Amyloid beta-Peptides/metabolism* ; Amyloid beta-Protein Precursor/metabolism* ; Carotenoids/pharmacology* ; Humans ; Cell Line, Tumor ; Reactive Oxygen Species/metabolism* ; Apoptosis/drug effects* ; Calcium/metabolism*

Rosacea is a common chronic inflammatory skin disease that predominantly affects the central face. It can impair appearance and cause various discomforts, thus negatively impacting patients' physical and mental well-being as well as their quality of life. Its pathophysiological mechanisms involve multiple factors. Studies have confirmed that ultraviolet radiation plays a significant role in the pathogenesis of rosacea, affecting skin tissues, cells, DNA, and proteins, and inducing oxidative damage. Ultraviolet can lead to the occurrence and development of rosacea by up-regulating the expression of LL-37, matrix metalloproteinase, vascular endothelial growth factor, and reactive oxygen species, and influence their interactions, thereby triggering inflammatory responses, altering the dermal matrix, and promoting capillary dilation and neovascularization, which contribute to the onset and progression of rosacea. Exploring the role of ultraviolet in the pathogenesis of rosacea can provide new strategies for protection and treatment, and enhance awareness of ultraviolet protection among patients with rosacea.
Humans ; Rosacea/metabolism* ; Ultraviolet Rays/adverse effects* ; Cathelicidins ; Reactive Oxygen Species/metabolism* ; Antimicrobial Cationic Peptides/metabolism* ; Matrix Metalloproteinases/metabolism* ; Vascular Endothelial Growth Factor A/metabolism* ; Skin/metabolism*

OBJECTIVE: To investigate the mechanism of circular RNA RAD18 (CircRAD18 ) in regulating daunorubicin (DNR) resistance in acute myeloid leukemia (AML) cells through the miR-185-5p/hepatoma-derived growth factor ( HDGF) axis. METHODS: Real-time fluorescence quantitative PCR and immunoblotting were applied to detect the expression of CircRAD18 , miR-185-5p, and HDGF in human AML cell lines HL-60, U937, and human AML drug-resistant cell line KG1a. KG1a cells were cultured in vitro and randomly divided into control group, DNR group, DNR+negative control group, DNR+CircRAD18 knockdown group, and DNR+CircRAD18 knockdown+miR-185-5p inhibitor group. After transfection, real-time fluorescence quantitative PCR and immunoblotting were applied to detect the expression of CircRAD18 , miR-185-5p, and HDGF of cells, CCK-8 method and Ki-67 immunofluorescence staining were applied to detect cell proliferation, flow cytometry was applied to detect cell apoptosis, and immunoblotting was applied to detect the expression of cell proliferation, apoptosis and drug resistance related proteins in each group. The double luciferase reporter gene experiment was applied to detect the targeting regulation of CircRAD18 on miR-185-5p, and miR-185-5p on HDGF in KG1a cells. RESULTS: Compared with HL-60 and U937 cells, the expression of CircRAD18 , and HDGF mRNA and protein in KG1a cells increased (all P <0.05), while miR-185-5p decreased ( P <0.05). Compared with the control group, the CircRAD18 expression, HDGF mRNA and protein expression, cell viability, proliferation rate, and PCNA, Bcl-2, BCRP, and P-gp protein expression in the DNR+CircRAD18 knockdown group decreased (all P <0.05), while miR-185-5p expression, apoptosis rate, and Bax protein expression increased (all P <0.05). There were no obvious changes in all indicators of cells in the DNR group compared with control group ( P >0.05). Compared with the DNR group, the CircRAD18 expression, HDGF mRNA and protein expression, cell viability, proliferation rate, PCNA, Bcl-2, BCRP, and P-gp protein expression in the DNR+CircRAD18 knockdown group decreased (all P < 0.05), while miR-185-5p expression, apoptosis rate, and Bax protein expression increased (all P < 0.05). There were no obvious changes in all indicators of cells in the DNR+negative control group compared with DNR group (P >0.05). Compared with the DNR+CircRAD18 knockdown group, the HDGF mRNA and protein expression, cell viability, proliferation rate, PCNA, Bcl-2, BCRP, and P-gp protein expression in the DNR+CircRAD18 knockdown+miR-185-5p inhibitor group increased (all P < 0.05), while miR-185-5p expression, apoptosis rate, and Bax protein expression decreased (all P < 0.05). CircRAD18 was able to target and down-regulate the expression of miR-185-5p in KG1a cells, and miR-185-5p was able to target and down-regulate the HDGF expression. CONCLUSION Knocking down CircRAD18 can reduce HDGF expression by up-regulating miR-185-5p, thereby weakening DNR resistance in AML cells, inhibiting KG1a cell proliferation under DNR treatment, and promoting apoptosis.
Humans ; MicroRNAs/metabolism* ; Leukemia, Myeloid, Acute ; Daunorubicin/pharmacology* ; Drug Resistance, Neoplasm ; Apoptosis ; RNA, Circular ; Intercellular Signaling Peptides and Proteins/metabolism* ; Cell Proliferation ; HL-60 Cells ; Cell Line, Tumor