Decursinol Angelate Inhibits LPS-Induced Macrophage Polarization through Modulation of the NFκB and MAPK Signaling Pathways

Preventive Role of Salsalate in Diabetes Is Associated With Reducing Intestinal Inflammation Through Improvement of Gut Dysbiosis in ZDF Rats

A safe and effective approach is needed to prevent and reduce the incidence of diabetes worldwide. The hypoglycemic efficacy of salicylic acid (salsalate, SAL), which has anti-inflammatory properties, has been empirically demonstrated in studies conducted at the Joslin Diabetes Center and elsewhere. Here, we investigated the potential role of SAL in preventing the onset of diabetes in Zucker diabetic fatty (ZDF) rats and attempted to elucidate its underlying mechanisms. ZDF and Zucker lean (ZL) rats were administered a high-fat diet with or without SAL intervention, and their relative rates of diabetes were compared. Our results showed that all rats in the placebo group developed diabetes, whereas only 10% of the SAL-treated rats presented with impaired glucose tolerance (IGT). None of the latter progressed to diabetes. Relative to the untreated rats, SAL lowered plasma glucagon and insulin while improving insulin sensitivity and β-cell function. SAL may protect against hyperglycemia by increasing the microbial diversity, ameliorating gut dysbiosis, restoring intestinal epithelial cell connections, inhibiting endotoxin influx into the blood, and attenuating inflammation. Together, these findings suggest that SAL may be a candidate prophylactic therapy against diabetes. The protective role of SAL may be attributed to its ability to reduce intestinal inflammation and improve gut dysbiosis.

PEP-1-GLRX1 Protein Exhibits Anti-Inflammatory Effects by Inhibiting the Activation of MAPK and NF-κB Pathways in Raw 264.7 Cells

Glutaredoxin 1 (GLRX1) has been recognized as an important regulator of redox signaling. Although GLRX1 plays an essential role in cell survival as an antioxidant protein, the function of GLRX1 protein in inflammatory response is still under investigation. Therefore, we wanted to know whether transduced PEP-1-GLRX1 protein inhibits lipopolysaccharide (LPS)- and 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced inflammation. In LPS-exposed Raw 264.7 cells, PEP-1-GLRX1 inhibited cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), activation of mitogen activated protein kinases (MAPKs) and nuclear factor-kappaB (NF-βB) expression levels. In a TPA-induced mouse-ear edema model, topically applied PEP-1-GLRX1 transduced into ear tissues and significantly ameliorated ear edema. Our data reveal that PEP-1-GLRX1 attenuates inflammation in vitro and in vivo, suggesting that PEP-1-GLRX1 may be a potential therapeutic protein for inflammatory diseases.

Decursin negatively regulates LPS-induced upregulation of the TLR4 and JNK signaling stimulated by the expression of PRP4 in vitro

The current investigation was carried out to analyze the correlation of bacterial lipopolysaccharide (LPS) and pre-mRNA processing factor 4B (PRP4) in inducing inflammatory response and cell actin cytoskeleton rearrangement in macrophages (Raw 264.7) and colorectal (HCT116) as well as skin cancer (B16-F10) cells. Cell lines were stimulated with LPS, and the expression of PRP4 as well as pro-inflammatory cytokines and proteins like IL-6, IL-1β, TLR4, and NF-κB were assayed. The results demonstrated that LPS markedly increased the expression of PRP4, IL-6, IL-1β, TLR4, and NF-κB in the cells. LPS and PRP4 concomitantly altered the morphology of cells from an aggregated, flattened shape to a round shape. Decursin, a pyranocoumarin from Angelica gigas, inhibited the LPS and PRP4-induced inflammatory response, and reversed the induction of morphological changes. Finally, we established a possible link of LPS with TLR4 and JNK signaling, through which it activated PRP4. Our study provides molecular insights for LPS and PRP4-related pathogenesis and a basis for developing new strategies against metastasis in colorectal cancer and skin melanoma. Our study emphasizes that decursin may be an effective treatment strategy for various cancers in which LPS and PRP4 perform a critical role in inducing inflammatory response and morphological changes leading to cell survival and protection against anti-cancer drugs.

Caldecrin inhibits lipopolysaccharide-induced pro-inflammatory cytokines and M1 macrophage polarization through the immunoreceptor triggering receptor expressed in myeloid cells-2

Caldecrin was previously isolated as a serum calcium-decreasing factor from the pancreas and is known to suppress receptor activator of nuclear factor-κB ligand (RANKL)-induced calcium oscillation pathways in osteoclasts. Here, we explored the effects of caldecrin on lipopolysaccharide (LPS)-Toll-like receptor-4 (TLR-4) signaling pathways in macrophages. Caldecrin inhibited the LPS-induced gene expression of pro-inflammatory cytokines and M1 macrophage polarization in mouse bone marrow macrophages and the RAW264.7 mouse macrophage cell line. Next, we focused on triggering receptor expressed in myeloid cells-2 (TREM-2) as a co-receptor common to RANKL receptor and TLR-4, and established Trem2-KO RAW264.7 cells, in which Trem2 gene was deleted using the CRISPR/Cas9 system. Caldecrin-mediated alterations in pro-inflammatory cytokine expression and M1 macrophage polarization were not observed in Trem2-KO RAW264.7 cells. These results suggest that caldecrin is not only an inhibitor of osteoclast activation but also a negative regulator of LPS-induced inflammatory responses, functioning via TREM-2.

Modified ZIF-8 Nanoparticles Attenuate Osteoarthritis by Reprogramming the Metabolic Pathway of Synovial Macrophages

Accumulating evidence suggests that activation of proinflammatory M1-type macrophages in the synovium plays a vital role in the progression of osteoarthritis (OA). Redundant nitric oxide (NO) and hydrogen peroxide (H₂O₂) are key factors that drive macrophages to polarize to the M1 type. Herein, modified zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) have been synthesized. By regulating intracellular gases and reprogramming the metabolism phenotype, modified NPs transformed macrophage polarization from proinflammatory M1 to anti-inflammatory M2 phenotype. Specifically, S-methylisothiourea hemisulfate salt was loaded into ZIF-8 NPs to inhibit inducible nitric oxide synthase, hence reducing NO production. Catalase was encapsulated to catalyze the production of oxygen (O₂) from H₂O₂. Results demonstrated that modified NPs were capable of catalyzing H₂O₂ to produce O₂ and eliminate NO, hence inhibiting hypoxia-inducible factor 1α, further rescuing mitochondrial function. Moreover, anti-CD16/32 antibody modification could prolong the retention time of NPs in knee joints of OA mice with anterior cruciate ligament transection. More significantly, modified NPs suppressed M1 macrophages and up-regulated M2 macrophage infiltration in the synovium, further inhibiting cartilage degeneration. This ZIF-8 NP-based gas regulation and metabolic reprogramming strategy may pave a new avenue for OA treatment.

IL-27 is elevated in sepsis with acute hepatic injury and promotes hepatic damage and inflammation in the CLP model

BACKGROUND

Immuno-inflammation plays an important role in the pathophysiological process of sepsis-associated acute hepatic injury (AHI). Interleukin 27 (IL-27) is an important inflammatory regulator; however, its role in this condition is not clear.

METHODS

The clinical data and IL-27 serum levels in sepsis patients with or without AHI were analysed. Classical caecal ligation puncture (CLP) models were established in wild-type (WT) and IL-27 receptor (WSX-1)-deficient (IL-27R^-/-) mice. In addition, exogenous IL-27 was injected into these mice, and the levels of IL-27, IL-6, and tumour necrosis factor alpha (TNF-α) in the serum and liver were then measured by enzyme-linked immunoassay (ELISA), quantitative PCR, and Western blotting. The severity of liver damage was evaluated by haematoxylin and eosin staining of liver tissue, TUNEL assay and evaluation of alanine aminotransferase (ALT) and aspartate transaminase (AST) serum levels. Furthermore, the effects of IL-27 on the levels of phosphorylated c-Jun N-terminal kinase (JNK) in macrophages were assessed by Western blotting, and the effects of IL-27 on the expression of IL-6 and TNF-α in macrophages were assessed by ELISA.

RESULTS

IL-27 was elevated in sepsis patients with acute hepatic injury, which correlated with the Acute Physiologic Assessment and Chronic Health Evaluation II (APACHEII) scores, Sequential Organ Failure Assessment (SOFA) scores, and procalcitonin, C-reactive protein, IL-6, and TNF-α expression. In the CLP-WT group, IL-27 was highly expressed in the serum and liver, which correlated with the elevated content of ALT, AST, TNF-α, IL-6, and p-JNK in the serum and liver and the pathological injury of the liver. In CLP-IL-27R^-/- group, however, the levels of ALT, AST, TNF-α, IL-6, and p-JNK in the serum and liver and the pathological injury of the liver were decreased. Treatment with exogenous IL-27 led to a further increase in these cytokines in WT mice after CLP. IL-27 treatment and lipopolysaccharide stimulation in vitro increased the expression of p-JNK, IL-6, and TNF-α in macrophages, and these changes were decreased by a JNK signalling pathway inhibitor.

CONCLUSION

IL-27 is elevated in sepsis patients, especially those with acute hepatic injury. In addition, IL-27 can promote inflammatory reactions in the CLP-induced hepatic injury mice model.

Decursinol angelate ameliorates 12-O-tetradecanoyl phorbol-13-acetate (TPA) -induced NF-κB activation on mice ears by inhibiting exaggerated inflammatory cell infiltration, oxidative stress and pro-inflammatory cytokine production

Decursinol angelate (DA) is a pyranocoumarin purified from the roots of Angelica gigas. Here, we synthesized DA and determined its anti-inflammatory potential on TPA-induced mice ear inflammation. First, we evaluated the non-toxic behaviour of DA on HaCaT cells. Additionally, we observed the free radical scavenging potential of DA at 60 μM to be 50%. This finding was further supported by nitric oxide assay, malondialdehyde assay, H2DCFDA staining and western blotting analysis of antioxidant enzymes. DA also suppressed the activation and polarization of macrophage phagocytic activity on RAW 264.7 cells. We further evaluated the expression of ICAM-1, MCP-1, MIP-2 and MIP-1β on in-vivo model system. Consequently, DA significantly reduced the production of NF-κB and COX-2 induced proinflammatory cytokine levels on TPA induced ear edema. Inhibition of MAPK and transcriptional factor NF-κB was also validated by western blotting analysis of p-ERK, p-p38, IKKα, IKKγ, IκBα, NF-κB-p65. Immunohistochemistry and immunofluorescence staining of NFκB-p65, TNF-α and IL-1β were also performed to support the findings. Conclusively, these results suggest that topical administration of DA significantly inhibited the expression of pro-inflammatory cytokines by blocking the canonical NF-κB and MAPK pathway. Therefore, we suggest DA as a potent therapeutic compound against skin inflammation related diseases.

Tat-ATOX1 inhibits inflammatory responses via regulation of MAPK and NF-κB pathways

Antioxidant 1 (ATOX1) protein has been reported to exhibit various protective functions, including antioxidant and chaperone. However, the effects of ATOX1 on the inflammatory response has not been fully elucidated. Thus, we prepared cell permeable Tat-ATOX1 and studied the effects on lipopolysaccharide (LPS)- and 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced inflammation. Experimental results showed that transduced Tat-ATOX1 protein significantly suppressed LPS-induced intracellular reactive oxygen species (ROS). Also, Tat-ATOX1 protein markedly inhibited LPS- and TPA-induced inflammatory responses by decreasing cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) and further inhibited phosphorylation of mitogen activated protein kinases (MAPKs; JNK, ERK and p38) and the nuclear factor-kappaB (NF-κB) signaling pathway. These results indicate that the Tat-ATOX1 protein has a pivotal role in inflammation via inhibition of inflammatory responses, suggesting Tat-ATOX1 protein may offer a therapeutic strategy for inflammation.

Anti-Inflammatory Effects of Aurantio-Obtusin from Seed of Cassia obtusifolia L. through Modulation of the NF-κB Pathway

Aurantio-obtusin, an anthraquinone compound, isolated from dried seeds of Cassia obtusifolia L. (syn. Senna obtusifolia; Fabaceae) and Cassia tora L. (syn. Senna tora). Although the biological activities of Semen Cassiae have been reported, the anti-inflammatory mechanism of aurantio-obtusin, its main compound, on RAW264.7 cells, remained unknown. We investigated the anti-inflammatory effect of aurantio-obtusin on lipopolysaccharide- (LPS)-induced RAW264.7 cells in vitro and elucidated the possible underlying molecular mechanisms. Nitric oxide production (NO) and prostaglandin E₂ (PGE₂) were measured by the Griess colorimetric method and enzyme-linked immunosorbent assay (ELISA), respectively. Protein expression levels of cyclooxygenase 2 (COX-2) were monitored by cell-based ELISA. Interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α) synthesis were analyzed using ELISA. The mRNA expression of nitric oxide synthase (iNOS), COX-2, and the critical pro-inflammatory cytokines (IL-6 and TNF-α) were detected by quantitative real-time PCR. Aurantio-obtusin significantly decreased the production of NO, PGE₂, and inhibited the protein expression of COX-2, TNF-α and IL-6, which were similar to those gene expression of iNOS, COX-2, TNF-α and IL-6 (p < 0.01). Consistent with the pro-inflammatory gene expression, the Aurantio-obtusin efficiently reduced the LPS-induced activation of nuclear factor-κB in RAW264.7 cells. These results suggested that aurantio-obtusin may function as a therapeutic agent and can be considered in the further development of treatments for a variety of inflammatory diseases. Further studies may provide scientific evidence for the use of aurantio-obstusin as a new therapeutic agent for inflammation-related diseases.