PRMT1 Inhibition Activates the Interferon Pathway to Potentiate Antitumor Immunity and Enhance Checkpoint Blockade Efficacy in Melanoma.

Despite the immense success of immune checkpoint blockade (ICB) in cancer treatment, many tumors, including melanoma, exhibit innate or adaptive resistance. Tumor-intrinsic T-cell deficiency and T-cell dysfunction have been identified as essential factors in the emergence of ICB resistance. Here, we found that protein arginine methyltransferase 1 (PRMT1) expression was inversely correlated with the number and activity of CD8+ T cells within melanoma specimen. PRMT1 deficiency or inhibition with DCPT1061 significantly restrained refractory melanoma growth and increased intratumoral CD8+ T cells in vivo. Moreover, PRMT1 deletion in melanoma cells facilitated formation of double-stranded RNA derived from endogenous retroviral elements (ERV) and stimulated an intracellular interferon response. Mechanistically, PRMT1 deficiency repressed the expression of DNA methyltransferase 1 (DNMT1) by attenuating modification of H4R3me2a and H3K27ac at enhancer regions of Dnmt1, and DNMT1 downregulation consequently activated ERV transcription and the interferon signaling. Importantly, PRMT1 inhibition with DCPT1061 synergized with PD-1 blockade to suppress tumor progression and increase the proportion of CD8+ T cells as well as IFNγ+CD8+ T cells in vivo. Together, these results reveal an unrecognized role and mechanism of PRMT1 in regulating antitumor T-cell immunity, suggesting PRMT1 inhibition as a potent strategy to increase the efficacy of ICB. SIGNIFICANCE: Targeting PRMT1 stimulates interferon signaling by increasing expression of endogenous retroviral elements and double-stranded RNA through repression of DNMT1, which induces antitumor immunity and synergizes with immunotherapy to suppress tumor progression.

Spermine is a natural suppressor of AR signaling in castration-resistant prostate cancer.

In castration-resistant prostate cancer (CRPC), clinical response to androgen receptor (AR) antagonists is limited mainly due to AR-variants expression and restored AR signaling. The metabolite spermine is most abundant in prostate and it decreases as prostate cancer progresses, but its functions remain poorly understood. Here, we show spermine inhibits full-length androgen receptor (AR-FL) and androgen receptor splice variant 7 (AR-V7) signaling and suppresses CRPC cell proliferation by directly binding and inhibiting protein arginine methyltransferase PRMT1. Spermine reduces H4R3me2a modification at the AR locus and suppresses AR binding as well as H3K27ac modification levels at AR target genes. Spermine supplementation restrains CRPC growth in vivo. PRMT1 inhibition also suppresses AR-FL and AR-V7 signaling and reduces CRPC growth. Collectively, we demonstrate spermine as an anticancer metabolite by inhibiting PRMT1 to transcriptionally inhibit AR-FL and AR-V7 signaling in CRPC, and we indicate spermine and PRMT1 inhibition as powerful strategies overcoming limitations of current AR-based therapies in CRPC.

Selective bromodomain and extra-terminal bromodomain inhibitor inactivates macrophages and hepatic stellate cells to inhibit liver inflammation and fibrosis.

Liver fibrosis occurs following inflammation triggered by the integrated actions of activated liver-resident macrophages (Kupffer cells) and hepatic stellate cells (HSCs), and the multiplicity of these mechanisms complicates drug therapy. Here, we demonstrate that the selective bromodomain and extra-terminal (BET) bromodomain inhibitor compound38 can block both the Janus kinase-signal transducer and activator of transcription and mitogen-activated protein kinase signaling pathways in macrophages, which decreased their secretion of proinflammatory cytokines in a dose-dependent manner. The inactivation of macrophages attenuated lipopolysaccharide-induced injurious inflammation concurrent with a reduction in F4/80+ cells, proinflammatory cytokine levels, and neutrophil infiltration. Moreover, compound 38 inhibited the Wnt/ß-catenin and transforming growth factor-beta/SMAD signaling pathways to abolish the activation of HSCs. In vivo, compound 38 significantly decreased the collagen deposition and fibrotic area of a CCl4-induced liver fibrosis model, and restored the deficiency of activated HSCs and the upregulation of liver inflammation. These results highlight the potential role of compound 38 in treating liver fibrosis considering its simultaneous inhibitory effects on liver inflammation and related fibrosis.

Yixin Ningshen Tablet Alleviates Comorbidity of Myocardial Infarction and Depression by Enhancing Myocardial Energy Metabolism and Increasing Availability of Monoamine Neurotransmitter.

OBJECTIVE: To investigate the therapeutic effect of Yixin Ningshen Tablet (YXNS) on comorbidity of myocardial infarction (MI) and depression in rats and explore the underlying mechanism. METHODS: The Sprague-Dawley rats were randomly divided into 5 groups with 7 rats in each group according to their weights, including control, model, fluoxetine (FLXT, 10 mg/kg), low-dose YXNS (LYXNS, 100 mg/kg), and high-dose YXNS (HYXNS, 300 mg/kg) groups. All rats were pretreated with corresponding drugs for 12 weeks. The rat model of MI and depression was constructed by ligation of left anterior descending coronary artery and chronic mild stress stimulation. The echocardiography, sucrose preference test, open field test, and forced swim test were performed. Myocardial infarction (MI) area and myocardial apoptosis was also detected. Serum levels of interleukin (IL)-6, IL-1ß, tumor necrosis factor-α (TNF-α), 5-hydroxytryptamine (5-HT), adrenocorticotrophic hormone (ACTH), corticosterone (CORT), and norepinephrine (NE) were determined by enzyme linked immunosorbent assay. The proteins of adenosine 5'-monophosphate -activated protein kinase (AMPK), p-AMPK, peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), and nuclear respiratory factor 1 (NRF1) in heart were detected by Western blot analysis. The expression levels of TNF-α, IL-6, indoleamine 2,3-dioxygenase (IDO1), kynurenine 3-monooxygenase (KMO), and kynureninase (KYNU) in hippocampus were detected by real-time quantitative polymerase chain reaction. RESULTS: Compared with the model group, the cardiac function of rats treated with YXNS improved significantly (P<0.01). Meanwhile, YXNS effectively reduced MI size and cardiomyocytes apoptosis of rats (P<0.01 or P<0.05), promoted AMPK phosphorylation, and increased PGC-1α protein expression (P<0.01 or P<0.05). HYXNS significantly increased locomotor activity of rats, decreased the levels of TNF-α, IL-6 and IL-1ß, and increased the serum levels of 5-HT, NE, ACTH, and CORT (all P<0.05). Moreover, HYXNS decreased the mRNA expressions of IDO1, KMO and KYNU (P<0.05). CONCLUSIONS: YXNS can relieve MI by enhancing myocardial energy metabolism. Meanwhile, YXNS can alleviate depression by resisting inflammation and increasing availability of monoamine neurotransmitters. It may be used as a potential drug to treat comorbidity of MI and depression.

BIG1 controls macrophage pro-inflammatory responses through ARF3-mediated PI(4,5)P2 synthesis.

Sepsis is caused by a dysregulated host inflammatory response to serious infections resulting in life-threatening organ dysfunction. The high morbidity and mortality make sepsis still a major clinical problem. Here, we investigated the roles of Brefeldin A-inhibited guanine nucleotide-exchange factor 1 (BIG1) in the pathogenesis process of sepsis and the underlying mechanisms. We found myeloid cell-specific BIG1 knockout (BIG1 cKO) significantly reduced the mortality and organ damage in LPS-induced and CLP-induced polymicrobial sepsis mouse model. The serum concentration and mRNA expression of pro-inflammatory cytokines including TNF-α, IL-6, IL-1ß, and IL-12 were obviously decreased in BIG1 cKO mice. In bone marrow-derived macrophages or THP-1 cells, BIG1 deficiency caused an inhibited ARF3 activation, which reduced PI(4,5)P2 synthesis and the recruitment of TIRAP to the plasma membrane through inhibiting the activation of PIP5K induced by LPS, and eventually resulted in the inhibitory activity of TLR4-MyD88 signaling pathway. These results reveal a crucial new role of BIG1 in regulating macrophage inflammation responses, and provide evidence for BIG1 as a potential promising therapeutic target in sepsis.

Sorting Nexin 10 Mediates Metabolic Reprogramming of Macrophages in Atherosclerosis Through the Lyn-Dependent TFEB Signaling Pathway.

RATIONALE: SNX10 (sorting nexin 10) has been reported to play a critical role in regulating macrophage function and lipid metabolism. OBJECTIVE: To investigate the precise role of SNX10 in atherosclerotic diseases and the underlying mechanisms. METHODS AND RESULTS: SNX10 expression was compared between human healthy vessels and carotid atherosclerotic plaques. Myeloid cell-specific SNX10 knockdown mice were crossed onto the APOE-/- (apolipoprotein E) background and atherogenesis (high-cholesterol diet-induced) was monitored for 16 weeks. We found that SNX10 expression was increased in atherosclerotic lesions of aortic specimens from humans and APOE-/- mice. Myeloid cell-specific SNX10 deficiency (Δ knockout [KO]) attenuated atherosclerosis progression in APOE-/- mice. The population of anti-inflammatory monocytes/macrophages was increased in the peripheral blood and atherosclerotic lesions of ΔKO mice. In vitro experiments showed that SNX10 deficiency-inhibited foam cell formation through interrupting the internalization of CD36, which requires the interaction of SNX10 and Lyn-AKT (protein kinase B). The reduced Lyn-AKT activation by SNX10 deficiency promoted the nuclear translocation of TFEB (transcription factor EB), thereby enhanced lysosomal biogenesis and LAL (lysosomal acid lipase) activity, resulting in an increase of free fatty acids to fuel mitochondrial fatty acid oxidation. This further promoted the reprogramming of macrophages and shifted toward the anti-inflammatory phenotype. CONCLUSIONS: Our data demonstrate for the first time that SNX10 plays a crucial role in diet-induced atherogenesis via the previously unknown link between the Lyn-Akt-TFEB signaling pathway and macrophage reprogramming, suggest that SNX10 may be a potentially promising therapeutic target for atherosclerosis treatment.

SNX10 (sorting nexin 10) inhibits colorectal cancer initiation and progression by controlling autophagic degradation of SRC.

The non-receptor tyrosine kinase SRC is a key mediator of cellular protumorigenic signals. SRC is aberrantly over-expressed and activated in more than 80% of colorectal cancer (CRC) patients, therefore regulation of its stability and activity is essential. Here, we report a significant down regulation of SNX10 (sorting nexin 10) in human CRC tissues, which is closely related to tumor differentiation, TNM stage, lymph node metastasis and survival period. SNX10 deficiency in normal and neoplastic colorectal epithelial cells promotes initiation and progression of CRC in mice. SNX10 controls SRC levels by mediating autophagosome-lysosome fusion and SRC recruitment for autophagic degradation. These mechanisms ensure proper controlling of the activities of SRC-STAT3 and SRC-CTNNB1 signaling pathways by up-regulating SNX10 expression under stress conditions. These findings suggest that SNX10 acts as a tumor suppressor in CRC and it could be a potential therapeutic target for future development.Abbreviations: ACTB: actin beta; ATG5: autophagy related 5; ATG12: autophagy related 12; CQ: chloroquine; CRC: colorectal cancer; CTNNB1: catenin beta 1; EBSS: Earle's balanced salt solution; KO: knockout; LAMP1: lysosomal associated membrane protein 1; LAMP2: lysosomal associated membrane protein 2; MAP1LC3: microtubule associated protein 1 light chain 3; MKI67: marker of proliferation Ki-67; mRNA: messenger RNA; PX: phox homology; RT-qPCR: real time quantitative polymerase chain reaction; siRNA: small interfering RNA; SNX10: sorting nexin 10; SQSTM1: sequestosome 1; SRC: SRC proto-oncogene, non-receptor tyrosine kinase; STAT3: signal transducer and activator of transcription 3; WT: wild type.

Astragaloside IV reverses simvastatin-induced skeletal muscle injury by activating the AMPK-PGC-1α signalling pathway.

In this study, we investigated the effect of astragaloside IV on skeletal muscle energy metabolism disorder caused by statins and explored the possible mechanisms. High-fat diet-fed apolipoprotein E knockout (ApoE-/- ) mice performed aerobic exercise and were administered simvastatin, simvastatin + trimetazidine, or simvastatin + astragaloside IV by gavage. At the end of treatment, exercise performance was assessed by the hanging grid test, forelimb grip test, and running tolerance test. Moreover, plasma lipid and creatine kinase concentrations were measured. After sacrifice, the gastrocnemius muscle was used to assess muscle morphology, and energy metabolism was evaluated by determining the concentration of lactic acid and the storage capacity of adenosine triphosphate and glycogen. Mitochondrial function was assessed by measuring mitochondrial complex III and citrate synthase activity and membrane potential. In addition, oxidative stress was assessed by determining the level of hydrogen peroxide. Finally, using western blotting and reverse transcription polymerase chain reaction, we explored the mechanism of astragaloside IV in alleviating simvastatin-induced muscle injury. Our results demonstrated that astragaloside IV reversed simvastatin-induced muscle injury without affecting the lipid-lowering effect of simvastatin. Moreover, astragaloside IV promoted the phosphorylation of AMPK and activated PGC-1α, which upregulated the expression of NRF1 to enhance energy metabolism and inhibit skeletal muscle cell apoptosis.

Total Glucosides of Paeony protects against collagen-induced mouse arthritis via inhibiting follicular helper T cell differentiation.

BACKGROUND: The development of rheumatoid arthritis (RA) is related to germinal center (GC) response and autoreactive T cells, which mediate adaptive immunity and play an important role in stimulating the production of autoantibodies and pro-inflammatory cytokines by B cells and macrophages. Total Glucosides of Paeony (TGP) has anti-inflammatory, immunomodulatory and analgesic effects and is widely used to treat RA. However, few studies investigated whether the therapeutic effect of TGP is associated with the inhibition of autoimmune response. PURPOSE: The aim of this study was to investigate the effects and mechanisms of TGP on RA. STUDY DESIGN: Type II collagen-induced arthritis (CIA) mouse model was used, and TGP and paeoniflorin were intragastrically treated. METHODS: DBA/1 mice were divided into 5 groups: control, model, positive drug (paeoniflorin) and high- and low-dose TGP group. After 21 days of intragastric administration, the pathological change, inflammation expression and molecular mechanism of each group of mice were detected by Micro-CT, histochemical analysis, ELLSA, Western blot, RT-qPCR and flow cytometry. RESULTS: Our study found that TGP treatment effectively improved inflammation and joint destruction in CIA mice. It reduced the production of serum IgG2a and pro-inflammatory cytokines, including serum interleukin (IL)-21, tumor necrosis factor (TNF)-α and IL-6, and the phosphorylation of NF-κB p65 and STAT3 in a dose-dependent manner. More importantly, TGP could suppress the frequency of germinal center B cells and Tfh cells in the spleen. CONCLUSION: TGP can not only improve symptoms, but also inhibit bone destruction. The therapeutic effect of TGP on CIA is mainly achieved by inhibiting spleen Tfh cell differentiation and GC formation through STAT3 signaling pathway.

Asperosaponin VI protects against bone destructions in collagen induced arthritis by inhibiting osteoclastogenesis.

BACKGROUND: Bone destructive diseases like rheumatoid arthritis (RA), osteoporosis and bone metastatic tumors are mainly mediated by over-activated osteoclasts. Asperosaponin VI (AVI), isolated from the rhizome of Dipsacus asper, belongs to triterpenoid saponins. It has multiple physiological activities but its effects on RA, especially on osteoclast differentiation and activation are still unclear. PURPOSE: Explore the protective role of AVI on collagen induced arthritis (CIA) in vivo and RANKL induced osteoclastogenesis in vitro. METHODS: The effects of AVI on cell viability and RANKL-induced osteoclastogenesis, actin ring formation, bone resorption activity as well as on osteoclast specific gene and protein expression were tested using bone marrow derived monocytes (BMMs). Paws from CIA mice were used for micro-CT, HE and TRAP staining, real-time PCR and western blot. Sera were used for cytokine analysis by ELISA. The signaling pathways were detected using western blot, real-time PCR and immunofluorescence assay. RESULTS: AVI significantly inhibited RANKL-induced osteoclast formation and bone resorption activity by suppressing the formation of actin ring. It also inhibited the expression of various osteoclatogenesis marker genes and signaling pathways. AVI protected arthritis in vivo by suppressing inflammation and bone loss. CONCLUSION: AVI exerts its anti-osteoclastogenic activity both in vitro and in vivo by inhibiting RANKL-induced osteoclast differentiation and function. Thus, our studies demonstrate a potential therapeutic role for AVI in preventing or inhibiting RANKL-mediated osteolytic bone diseases.

Capsaicin-loaded folic acid-conjugated lipid nanoparticles for enhanced therapeutic efficacy in ovarian cancers.

In this study, folic acid-conjugated lipid nanoparticles were successfully prepared to enhance the active targeting of capsaicin (CAP) in ovarian cancers. The particles were nanosized and exhibited a controlled release of drug in the physiological conditions. The folic acid (FA)-conjugated system exhibited a remarkably higher uptake of nanoparticles in the cancer cells compared to that of non-targeted system. The folate-conjugated CAP-loaded lipid nanoparticles (CFLN) upon interacting with cancer cells were internalized via receptor-mediated endocytosis mechanism and resulted in higher concentration in the cancer cells. Consistently, CFLN showed a remarkably higher toxic effect compared to that of non-targeted nanoparticle system. CFLN showed significantly higher cancer cell apoptosis with nearly 39% of cells in apoptosis chamber (early and late) compared to only ∼21% and ∼11% for CAP-loaded lipid nanoparticles (CLN) and CAP. The loading of drug in the lipid nanoparticle system extended the drug retention in the blood circulation and allowed the active targeting to specific cancer cells. The prolonged circulation of drug attributed to the antifouling property of polyethylene glycol molecule in the structure. Overall, study highlights that using targeting moiety could enhance the therapeutic response of nanomedicines in the treatment of solid tumors.