Herbal compound cepharanthine attenuates inflammatory arthritis by blocking macrophage M1 polarization.

OBJECTIVE: Cepharanthine (CEP) is a drug candidate for tumor, viral infection, and some inflammatory diseases, but its effect on rheumatoid arthritis (RA) and the underlying mechanism are incompletely understood. METHODS: CEP was administered intraperitoneally to a collagen-induced arthritis (CIA) model. Joints went radiological and histological examination and serum cytokines were examined with cytometry-based analysis. M1 macrophages were induced from THP-1 cells or mouse bone marrow-derived macrophages with LPS and IFN-γ. Bulk RNA-seq was performed on macrophage undergoing M1-polarizatioin. Western blotting was applied to determine pathways involved in monocyte chemotaxis and polarization. Glycolysis metabolites were measured by chemiluminescence while glycolytic enzymes were examined by quantitative PCR. RESULTS: We found CEP significantly ameliorated synovial inflammation and joint destruction of CIA mice. It downregulated TNF-α levels in serum and in joints. The number of M1 macrophages were reduced in CEP-treated mice. In vitro, CEP inhibited monocyte chemotaxis to MCP-1 by downregulating CCR2 and reducing ERK1/2 signaling. Additionally, CEP suppressed M1 polarization of macrophages induced by LPS and IFN-γ. Genes involved in IFN-γ signaling, IL-6-JAK/STAT3 signaling, glycolysis, and oxidative phosphorylation process were downregulated by CEP. Several enzymes critically involved in glycolytic metabolism were suppressed by CEP, which resulted in reduced citrate in M1-polarizing macrophages. The inhibitory effect of CEP on macrophage polarization might be attributed to the blockage of TLRs-MyD88/IRAK4-IRF5 signaling pathway together with suppression of overactivated glycolytic metabolism in M1-polarizing macrophages. CONCLUSION: CEP attenuated joint inflammation by suppressing monocyte chemotaxis and proinflammatory differentiation. It has the potential to be developed into a complementary or alternative therapy for RA.

Advances in mesenchymal stem cell-derived extracellular vesicles therapy for Sjogren's syndrome-related dry eye disease.

Sjogren's syndrome (SS) is a chronic autoimmune disorder that affects exocrine glands, particularly lacrimal glands, leading to dry eye disease (DED). DED is a common ocular surface disease that affects millions of people worldwide, causing discomfort, visual impairment, and even blindness in severe cases. However, there is no definitive cure for DED, and existing treatments primarily relieve symptoms. Consequently, there is an urgent need for innovative therapeutic strategies based on the pathophysiology of DED. Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic tool for various autoimmune disorders, including SS-related DED (SS-DED). A particularly intriguing facet of MSCs is their ability to produce extracellular vesicles (EVs), which contain various bioactive components such as proteins, lipids, and nucleic acids. These molecules play a key role in facilitating communication between cells and modulating a wide range of biological processes. Importantly, MSC-derived EVs (MSC-EVs) have therapeutic properties similar to those of their parent cells, including immunomodulatory, anti-inflammatory, and regenerative properties. In addition, MSC-EVs offer several notable advantages over intact MSCs, including lower immunogenicity, reduced risk of tumorigenicity, and greater convenience in terms of storage and transport. In this review, we elucidate the underlying mechanisms of SS-DED and discuss the relevant mechanisms and targets of MSC-EVs in treating SS-DED. In addition, we comprehensively review the broader landscape of EV application in autoimmune and corneal diseases. This review focuses on the efficacy of MSC-EVs in treating SS-DED, a field of study that holds considerable appeal due to its multifaceted regulation of immune responses and regenerative functions.

Fecal microbiota transplantation from patients with rheumatoid arthritis causes depression-like behaviors in mice through abnormal T cells activation.

Depression is common in patients with rheumatoid arthritis (RA); however, the precise mechanisms underlying a link between depression and RA remain unclear. Accumulating evidence suggests the role of gut-microbiota-brain axis in depression. In this study, we investigated whether collagen-induced arthritis (CIA) mice produce depression-like behaviors and abnormal composition of gut microbiota. Furthermore, we investigated whether fecal microbiota transplantation (FMT) from RA patients causes depression-like phenotypes in antibiotic cocktail (ABX)-treated mice. CIA mice displayed depression-like behaviors, increased blood levels of pro-inflammatory cytokine interleukin-6 (IL-6), decreased expression of synaptic proteins in the prefrontal cortex (PFC), and abnormal composition of gut microbiota. Furthermore, FMT from RA patients caused depression-like phenotypes, alterations of gut microbiota composition, increased levels of IL-6 and tumor necrosis factor-α (TNF-α), and downregulation of synaptic proteins in the PFC compared to FMT from healthy controls. There were correlations between relative abundance of microbiota and plasma cytokines, expression of synaptic proteins in the PFC or depression-like behaviors. Interestingly, FMT from RA patients induced T cells differentiation in Peyer's patches and spleen. Reduced percentage of Treg cells with an increase of Th1/Th2 index was observed in the mice after FMT from RA patients. These findings suggest that CIA mice exhibit depression-like behaviors, systemic inflammation, and abnormal composition of gut microbiota, and that FMT from RA patients produces depression-like behaviors in ABX-treated mice via T cells differentiation. Therefore, abnormalities in gut microbiota in RA patients may contribute to depression via gut-microbiota-brain axis.

Cinacalcet Targets the Neurokinin-1 Receptor and Inhibits PKCδ/ERK/P65 Signaling to Alleviate Dextran Sulfate Sodium-Induced Colitis.

Objective: Inflammatory bowel disease is an immune-mediated chronic inflammatory disease of the gastrointestinal tract for which curative drugs are currently not available. This study was performed to assess the therapeutic effects of cinacalcet on dextran sulfate sodium (DSS)-induced colitis. Methods: Primary macrophages obtained from bone marrow and the macrophage cell line RAW264.7 were used to examine the inhibitory effect of cinacalcet on cytokine production, the PKCδ/ERK/P65 signaling pathway, and NF-κB P65 translocation. Colitis was induced using DSS to assess the treatment effect of cinacalcet. Bioinformatics approaches were adopted to predict potential targets of cinacalcet, and a drug affinity responsive target stability (DARTs) assay was performed to confirm binding between cinacalcet and potential target. Results: In vivo analysis showed that cinacalcet reduced the disease activity score, prevented shortening of the colon, diminished inflammatory cell infiltration, and protected the structural integrity of the intestinal wall. Cinacalcet also reduced production of the inflammatory cytokines TNFα, IL-1ß, and IL-6 in the colon and sera of mice with DSS-induced colitis. In vitro studies revealed that cinacalcet suppressed the translocation of P65 and inhibited production of the inflammatory cytokines IL-1ß and IL-6. Mechanistic studies revealed that the target of cinacalcet was neurokinin-1 receptor (NK1R) and their binding was confirmed by a DARTs assay. Furthermore, the inhibition of NK-κB P65 activation was found to occur via the suppression of PKCδ/ERK/P65 signaling mediated by cinacalcet. Conclusion: Cinacalcet inhibits the activation of NF-κB and reduces the production of inflammatory cytokines by suppressing the PKCδ/ERK/P65 signaling pathway via targeting NK1R, suggesting that it can be used to treat inflammatory diseases, particularly colitis.

Abnormalities of the composition of the gut microbiota and short-chain fatty acids in mice after splenectomy.

The brain-gut-microbiota axis is a complex multi-organ bidirectional signaling system between the brain and microbiota that participates in the host immune system. The spleen, as the largest immune organ in the body, has a key role in the brain-gut-microbiota axis. Here, we investigated whether splenectomy could affect depression-like phenotypes and the composition of the gut microbiota in adult mice. In behavioral tests, splenectomy did not cause depression-like behaviors in mice. Conversely, splenectomy led to significant alterations in the diversity of gut microbes compared with the findings in control (no surgery) and sham-operated mice. In an unweighted UniFrac distance analysis, the boxplots representing the splenectomy group were distant from those representing the other two groups. We found differences in abundance for several bacteria in the splenectomy group at the taxonomic level compared with the other two groups. Finally, splenectomy induced significant changes in lactic acid and n-butyric acid levels compared with those in the other groups. Interestingly, there were significant correlations between the counts of certain bacteria and lactic acid (or n-butyric acid) levels in all groups. These data suggest that splenectomy leads to an abnormal composition of the gut microbiota. It is likely that the spleen-gut-microbiota axis plays a crucial role in the composition of the gut microbiota by regulating immune homeostasis.

Ingestion of Lactobacillus intestinalis and Lactobacillus reuteri causes depression- and anhedonia-like phenotypes in antibiotic-treated mice via the vagus nerve.

BACKGROUND: The brain-gut-microbiota axis plays a role in the pathogenesis of stress-related disorders such as depression. In this study, we examined the effects of fecal microbiota transplantation (FMT) in mice with antibiotic-treated microbiota depletion. METHODS: The fecal microbiota was obtained from mice subjected to chronic social defeat stress (CSDS) and control (no CSDS) mice. FMT from these two groups was performed to antibiotic-treated mice. 16S rRNA analysis was performed to examine the composition of gut microbiota. Furthermore, the effects of subdiaphragmatic vagotomy in depression-like phenotypes after ingestion of microbes were examined. RESULTS: The ingestion of fecal microbiota from CSDS-susceptible mice resulted in an anhedonia-like phenotype, higher plasma levels of interleukin-6 (IL-6), and decreased expression of synaptic proteins in the prefrontal cortex (PFC) in antibiotic-treated mice but not in water-treated mice. 16S rRNA analysis suggested that two microbes (Lactobacillus intestinalis and Lactobacillus reuteri) may be responsible for the anhedonia-like phenotype in antibiotic-treated mice after FMT. Ingestion of these two microbes for 14 days led to depression- and anhedonia-like phenotypes, higher plasma IL-6 levels, and decreased expression of synaptic proteins in the PFC of antibiotic-treated mice. Interestingly, subdiaphragmatic vagotomy significantly blocked the development of behavioral abnormalities, elevation of plasma IL-6 levels, and downregulation of synaptic proteins in the PFC after ingestion of these two microbes. CONCLUSIONS: These findings suggest that microbiota depletion using an antibiotic cocktail is essential for the development of FMT-induced behavioral changes and that the vagus nerve plays a key role in behavioral abnormalities in antibiotic-treated mice after the ingestion of L. intestinalis and L. reuteri. Therefore, it is likely that the brain-gut-microbiota axis participates in the pathogenesis of depression via the vagus nerve.

Abnormal expression of colony stimulating factor 1 receptor (CSF1R) and transcription factor PU.1 (SPI1) in the spleen from patients with major psychiatric disorders: A role of brain-spleen axis.

BACKGROUND: The colony stimulating factor 1 receptor (CSF1R) regulates microglia/macrophage proliferation, differentiation and survival; however, the precise role of this protein in psychiatric disorders is unknown. CSF1R is also known to interact with the transcription factor PU.1 (SPI1). Here we studied whether the expressions of CSF1R and SPI1 are altered in the postmortem samples (parietal cortex, cerebellum, spleen) from patients with major psychiatric disorders. METHODS: Protein expression of CSF1R and SPI1 in the parietal cortex, cerebellum and spleen from control, major depressive disorder (MDD), schizophrenia (SZ), and bipolar disorder (BD) groups was measured. RESULTS: Levels of CSF1R in the spleen, but not cerebellum and parietal cortex, from MDD and SZ groups were significantly lower than the control group. There was a positive correlation between CSF1R levels in the spleen and CSF1R levels in the parietal cortex in the all subjects from four groups. Furthermore, levels of SPI1 in the cerebellum and spleen from MDD and SZ groups were significantly higher than the control group. Levels of SPI1 in the parietal cortex were not different among the four groups. Interestingly, there was a negative correlation between CSF1R and SPI1 levels in the spleen of the all subjects from four groups. There was also a negative correlation between CSF1R and SPI1 levels in the spleen of MDD group. LIMITATIONS: The small number in each group may limit our interpretation. CONCLUSIONS: Abnormalities in CSF1R and SPI1 in the brain-spleen axis might, in part, play a role in the pathophysiology of MDD.

Betaine supplementation is associated with the resilience in mice after chronic social defeat stress: a role of brain-gut-microbiota axis.

BACKGROUND: The brain-gut-microbiota axis plays a role in the pathogenesis of stress-related psychiatric disorders; however, its role in the resilience versus susceptibility after stress remains unclear. Dietary nutrient betaine is suggested to affect the gut microbiome. Here, we examined whether betaine supplementation can affect anhedonia-like phenotype in mice subjected to chronic social defeat stress (CSDS). METHODS: CSDS was performed during betaine supplementation. Sucrose preference test and 16S rRNA analysis of fecal samples were performed. RESULTS: CSDS did not produce an anhedonia-like phenotype in the betaine-treated mice, but did induce an anhedonia-like phenotype in water-treated mice. Furthermore, CSDS treatment did not alter the plasma levels of interleukin-6 (IL-6) of betaine-treated mice whereas CSDS caused higher plasma levels of IL-6 in water-treated mice. Betaine supplementation ameliorated the abnormal diversity and composition of the microbiota in the host gut after CSDS. At the genus level, CSDS caused marked increases in the several bacteria of water-treated mice, but not betaine-treated mice. CSDS increased levels of short-chain fatty acids (i.e., succinic acid and acetic acid) in feces from water-treated mice, but not betaine-treated mice. Interestingly, there are positive correlations between short-chain fatty acids (i.e., succinic acid, acetic acid, butyric acid) and several bacteria among the groups. LIMITATIONS: Specific microbiome were not determined. CONCLUSIONS: These findings suggest that betaine supplementation contributed to resilience to anhedonia in mice subjected to CSDS through anti-inflammation action. Therefore, it is likely that betaine could be a prophylactic nutrient to prevent stress-related psychiatric disorders.

Beneficial effects of anti-RANKL antibody in depression-like phenotype, inflammatory bone markers, and bone mineral density in male susceptible mice after chronic social defeat stress.

Multiple lines of evidence suggest a link between depression and osteoporosis in elderly people. Receptor activator of nuclear factor-κB ligand (RANKL) plays a role in the pathology of osteoporosis, and anti-RANKL antibody has been used in the treatment of osteoporosis. In this study, we investigated whether anti-mouse RANKL antibody could attenuate depression-like phenotypes, inflammatory bone markers and bone mineral density (BMD) in male susceptible mice after chronic social defeat stress (CSDS). We measured plasma levels of inflammatory bone markers, including osteoprotegerin (OPG), RANKL, and osteopontin. A single intravenous injection of anti-RANKL (2 mg/kg) elicited rapid antidepressant effects in CSDS susceptible mice. Furthermore, anti-RANKL significantly improved the increased plasma levels of RANKL and decreased OPG/RANKL ratio in CSDS susceptible mice. Moreover, anti-RANKL significantly attenuated the decreased BMD in CSDS susceptible mice. Interestingly, there is a positive correlation between anhedonia-like behavior and OPG/RANKL ratio in mice. These findings demonstrate that anti-RANKL may have beneficial effects in depression-like phenotype and abnormalities in bone functions of CSDS susceptible mice. It is, therefore, likely that anti-human RANKL antibody (i.e., Denosumab) would be a potential therapeutic drug for depression and osteoporosis.

Dietary intake of glucoraphanin prevents the reduction of dopamine transporter in the mouse striatum after repeated administration of MPTP.

AIMS: Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder. Although diet may influence the development of PD, the precise mechanisms underlying relationship between diet and PD pathology are unknown. Here, we examined whether dietary intake of glucoraphanin (GF), the precursor of a natural antioxidant sulforaphane in cruciferous vegetables, can affect the reduction of dopamine transporter (DAT) in the mouse striatum after repeated administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). METHODS: Normal food pellet or 0.1% GF food pellet was given into male mice for 28 days from 8-week-old. Subsequently, saline (5 mL/kg × 3, 2-hour interval) or MPTP (10 mg/kg × 3, 2-hour interval) was injected into mice. Immunohistochemistry of DAT in the striatum was performed 7 days after MPTP injection. RESULTS: Repeated injections of MPTP significantly decreased the density of DAT-immunoreactivity in the mouse striatum. In contrast, dietary intake of 0.1% GF food pellet significantly protected against MPTP-induced reduction of DAT-immunoreactivity in the striatum. CONCLUSION: This study suggests that dietary intake of GF food pellet could prevent MPTP-induced dopaminergic neurotoxicity in the striatum of adult mice. Therefore, dietary intake of GF-rich cruciferous vegetables may have beneficial effects on prevention for development of PD.

Beneficial effects of (R)-ketamine, but not its metabolite (2R,6R)-hydroxynorketamine, in the depression-like phenotype, inflammatory bone markers, and bone mineral density in a chronic social defeat stress model.

Inflammatory bone markers may play a role in the antidepressant actions of (R)-ketamine in susceptible mice after chronic social defeat stress (CSDS). In this study, we compared the effects of (R)-ketamine and its final metabolite (2R,6R)-hydroxynorketamine (HNK) in depression-like phenotypes, inflammatory bone markers and bone mineral density (BMD) in CSDS susceptible mice. We measured plasma levels of inflammatory bone markers, which included osteoprotegerin (OPG), receptor activator of nuclear factor κB ligand (RANKL), and osteopontin after behavioral tests. (R)-ketamine, but not (2R,6R)-HNK, elicited rapid and sustained antidepressant effects in CSDS susceptible mice. Furthermore, (R)-ketamine, but not (2R,6R)-HNK, significantly improved the increased plasma levels of RANKL and decreased OPG/RANKL ratio in CSDS susceptible mice. Moreover, (R)-ketamine, but not (2R,6R)-HNK, significantly attenuated the decreased BMD in CSDS susceptible mice. These findings demonstrate that (R)-ketamine may have beneficial effects in depression-like phenotype and abnormalities in bone functions of CSDS susceptible mice. It is, therefore, likely that (R)-ketamine would be a potential therapeutic drug for abnormalities in bone metabolism in depressed patients.