CSTMP Exerts Anti-Inflammatory Effects on LPS-Induced Human Renal Proximal Tubular Epithelial Cells by Inhibiting TLR4-Mediated NF-κB Pathways

Purification, structural elucidation and biological activities of exopolysaccharide produced by the endophytic Penicillium javanicum from Millettia speciosa Champ

An acid polysaccharide, named HP, was produced by endophytic Penicillium javanicum MSC-R1 isolated from southern medicine Millettia speciosa Champ. The molecular weight of HP was 37.8 kDa and consisted of Ara f, Galр, Glcр, Manр, and GlcрA with a molar ratio of 1.09: 3.47: 68.48: 16.59: 8.85. The glycosidic linkage of HP was proven to be →3, 4)-α-D-Glcр-(1→6)-α-D-Manр-(1→, →3, 4)-α-D-Glcр-(1→4)-α-D-Glcр-(1→, →3), →6)-α-D-Manр-(1→4)-α-D-Glcр-(1→, →3), β-D-Galр-(1→3)-α-D-Glcр-(1→, →4), →5)-α-L-Ara f -(1→3)-α-D-Glcр-(1→, →4), →6)-α-D-Manр-(1→4)-α-D-GlcAр-(1→ and →4)-α-D-GlcAр-(1→4)-α-D-Glcр-(1→, →3). Additionally, 250 μg/mL of HP possessed nontoxicity to RAW 264.7 cells and exhibited anti-inflammation activity. HP could significantly restrain the amount of tumor necrosis factor-α, interleukin-6 and NO release in RAW264.7, which property is possibly associated with its abundant glucosidic linkage. These results indicated that HP could be regarded as a ponderable ingredient for the health-beneficial functional foods.

Paeoniflorin Inhibits LPS-Induced Activation of Splenic CD4+ T Lymphocytes and Relieves Pathological Symptoms in MRL/lpr Mice by Suppressing IRAK1 Signaling

Interleukin-1receptor-associated kinase 1 (IRAK1) plays a critical role in systemic lupus erythematosus (SLE). It was reported that SLE was associated with an inflammatory response mediated by defective immune tolerance, including overproduction of autoantibodies, chronic inflammation, and organ damage. Previous reports stated paeoniflorin (PF) had an immunosuppressive effect. The purpose of this study was to determine the anti-inflammatory effect of PF in SLE and its underlying mechanisms. Followed by induced with lipopolysaccharide (LPS), the splenocytes and the isolated CD4+ T lymphocytes of MRL/lpr mice were divided into three groups: control group, LPS group, and LPS + PF group, respectively. MRL/MP mice were used as the control group (treated with distilled water). The MRL/lpr mice were randomly divided into three groups: the model group (treated with distilled water), the prednisone group, and the PF group. The MRL/lpr mice were treated with prednisone acetate (5 mg/kg) and PF (25, 50, and 75 mg/kg) for eight weeks. Subsequently, ELISA, qRT-PCR, western blotting, HE, and Masson staining were performed to detect various indicators. The results of Cell Counting Kit-8 (CCK-8) showed that 10 μg/mL of LPS had the optimum effect on cell viability, and 50 μmol/L of PF had no obvious cytotoxicity to LPS-treated cells. PF reduced the expression level of IRAK1-nuclearfactor-κB (NF-κB) and its downstream inflammatory cytokines in the splenocytes and CD4+ T lymphocytes of MRL/lpr mice stimulated by LPS, especially in the latter. The serum antibody contents in the PF group mice were reduced, and the kidney damage was also alleviated accordingly. Moreover, the IRAK1/inhibitor of the nuclear factor-κB kinase (IKK)/NF-κB inhibitor (IκB)/NF-κB pathways was found to be involved in the anti-inflammation effect of PF in the kidney and spleen. In conclusion, it is thought that PF may have the potential to be used as a therapeutic agent to reduce the inflammatory activity of SLE. Inhibition of the IRAK1-NF-κB pathway may help formulate novel therapeutic tactics for SLE.

Expression of TRAF6 in peripheral blood B cells of patients with myasthenia gravis

Background

Tumor necrosis factor receptor-associated factor 6 (TRAF6) can regulate the activation of inflammatory signaling pathways by acting as an E3 ubiquitin ligase, which enhances B cell activation. This study aimed to evaluate the expression of TRAF6 in the peripheral blood B cells of myasthenia gravis (MG) patients and analyze the relationships between TRAF6 expression and clinical characteristics.

Method

In our study, the expression level of TRAF6 in peripheral blood B cells of 89 patients was measured by flow cytometry compared with that of healthy subjects. The effects of disease severity, MG classification and immunotherapy on TRAF6 expression level were also analyzed.

Results

In our study, TRAF6 expression was elevated in CD19⁺ B cells and CD19⁺CD27⁺ memory B cells in generalized MG (GMG) patients compared with ocular MG (OMG) patients (p = 0.03 and p = 0.03, respectively). There was a significant positive correlation between the TRAF6 expression level and disease severity in both OMG patients and GMG patients (CD19⁺ B cells: OMG: p < 0.001, r = 0.89; GMG: p = 0.001, r = 0.59; CD29⁺CD27⁺ B cells: OMG: p = 0.001, r = 0.80; GMG: p = 0.048, r = 0.38). TRAF6 expression was significantly elevated in CD19⁺ B cells and CD19⁺CD27⁺ memory B cells in GMG with acute aggravation compared with GMG in MMS (p = 0.009 and p = 0.028, respectively). In the eleven MG patients who were followed, TRAF6 expression in B cells and memory B cells was significantly decreased after treatment (p = 0.03 and p < 0.01, respectively).

Conclusion

TRAF6 is potentially a useful biomarker of inflammation in patients with MG, and might be used to evaluate the effectiveness of treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02833-9.

Tetramethylpyrazine: A Review of Its Antitumor Potential and Mechanisms

Cancer remains a major public health threat. The mitigation of the associated morbidity and mortality remains a major research focus. From a molecular biological perspective, cancer is defined as uncontrolled cell division and abnormal cell growth caused by various gene mutations. Therefore, there remains an urgent need to develop safe and effective antitumor drugs. The antitumor effect of plant extracts, which are characterized by relatively low toxicity and adverse effect, has attracted significant attention. For example, increasing attention has been paid to the antitumor effects of tetramethylpyrazine (TMP), the active component of the Chinese medicine Chuanqiong, which can affect tumor cell proliferation, apoptosis, invasion, metastasis, and angiogenesis, as well as reverse chemotherapeutic resistance in neoplasms, thereby triggering antitumor effects. Moreover, TMP can be used in combination with chemotherapeutic agents to enhance their effects and reduce the side effect associated with chemotherapy. Herein, we review the antitumor effects of TMP to provide a theoretical basis and foundation for the further exploration of its underlying antitumor mechanisms and promoting its clinical application.

Lipopolysaccharide reduces urethral smooth muscle contractility via cyclooxygenase activation

Lipopolysaccharide (LPS) is a component of gram-negative bacteria wall that elicits inflammatory response in the host through the toll-like receptor 4 (TLR4) activation. In the lower urinary tract (LUT), bacteria-derived LPS has been associated with lower urinary tract symptoms (LUTS); however, little is known about the effects of LPS in the urethral smooth muscle (USM). In the present study, we evaluated the functional and molecular effects of LPS in mouse USM in vitro, focusing on the LPS-induced TLR4-signaling pathway. Male C57BL6/JUnib and TLR4 knockout mice (TLR4 KO) were used. The USM contraction was performed in the presence of LPS (62.5-500 μg/mL), indomethacin (10 μM), L-NAME (100 μM), and TAK 242 (1 μM). The RT-PCR assay for the IL-1β, NF-kB, and COX-2 genes was also evaluated in the presence of LPS (125 μg/mL) and caspase 1 inhibitor (20 μM). Our results showed that LPS reduces mouse USM contraction elicited by phenylephrine and vasopressin. This LPS-induced urethral inhibitory effect was not reversed by the TLR4 inhibition or its absence in the TLR4 KO mice. Conversely, indomethacin (but not L-NAME) reversed the LPS-induced USM hypocontractility. Molecular protocols indicated upregulation of IL-1β, NF-kβ, and COX-2 mRNA upon LPS incubation, which were blunted by caspase 1 inhibition. Our data showed that LPS reduced mouse USM contraction independently of TLR4 activation, involving caspase 1 and IL1β, NF-kB, and COX-2 gene overexpression. Therefore, this alternative pathway might be a valuable target to reduce the LPS-induced urethral dysfunction under infection and inflammatory conditions.

Mechanism by which TRAF6 Participates in the Immune Regulation of Autoimmune Diseases and Cancer

Tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6), an E3 ubiquitin ligase, is a signal transduction molecule shared by the interleukin-1 receptor (IL-1R)/Toll-like receptor (TLR) family and the TNFR superfamily. TRAF6 has a unique TRAF domain and RING finger domain that mediate intracellular signaling events. In the immune system, TRAF6-mediated signaling has been shown to be critical for the development, homeostasis, and activation of a variety of immune cells, including B cells, T cells, dendritic cells, and macrophages. Although the pathogenesis and etiology of autoimmune diseases and cancer are not fully understood, it is worth noting that existing studies have shown that TRAF6 is involved in the pathogenesis and development of a variety of these diseases. Herein, we reviewed the role of TRAF6 in certain immune cells, as well as the function and potential effect of TRAF6 in autoimmune diseases and cancer. Our review indicates that TRAF6 may be a novel target for autoimmune diseases and cancer.

Jieduquyuziyin Prescription Suppresses Inflammatory Activity of MRL/lpr Mice and Their Bone Marrow-Derived Macrophages via Inhibiting Expression of IRAK1-NF-κB Signaling Pathway

Jieduquyuziyin prescription (JP) has been used to treat systemic lupus erythematosus (SLE). Although the effectiveness of JP in the treatment of SLE has been clinically proven, the underlying mechanisms have yet to be completely understood. We observed the therapeutic actions of JP in MRL/lpr mice and their bone marrow-derived macrophages (BMDMs) and the potential mechanism of their inhibition of inflammatory activity. To estimate the effect of JP on suppressing inflammatory activity, BMDMs of MRL/lpr and MRL/MP mice were treated with JP-treated serum, and MRL/lpr mice were treated by JP for 8 weeks. Among them, JP and its treated serum were subjected to quality control, and BMDMs were separated and identified. The results showed that in the JP group of BMDMs stimulated by Lipopolysaccharide (LPS) in MRL/lpr mice, the secretion of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) reduced, and the expressions of Interleukin-1 receptor-associated kinase 1 (IRAK1) and its downstream nuclear factor κB (NF-κB) pathway decreased. Meanwhile, the alleviation of renal pathological damage, the decrease of urinary protein and serum anti-dsDNA contents, the inhibition of TNF-α level, and then the suppression of the IRAK1-NF-κB inflammatory signaling in the spleen and kidney, confirmed that the therapeutic effect of JP. These results demonstrated that JP could inhibit the inflammatory activity of MRL/lpr mice and their BMDMs by suppressing the activation of IRAK1-NF-κB signaling and was supposed to be a good choice for the treatment of SLE.

Erythropoietin Treatment Ameliorates Lupus Nephritis of MRL/lpr Mice

An increasing body of data has shown that erythropoietin (EPO) plays multiple roles in inflammation control and immunoregulation. However, less attention has been given to its effects on lupus nephritis (LN). In this study, we investigated the therapeutic effects of EPO on LN in MRL/lpr mice, a well-studied animal model for lupus. MRL/lpr mice were randomly divided into an EPO and control group. Mice in the EPO group were treated with EPO; saline was given to the control group. Both groups were treated for 10 weeks. We analyzed the differences of general disease condition, histopathologic changes, Th lymphocytes subsets, and the expression of inflammatory factors of mice between the groups. Compared to the control group, mice in the EPO group showed less spleen hyperplasia, less urinary protein, and lower serum anti-dsDNA antibody; they also had lower renal histopathologic scores and less deposition of IgG/C3 within glomeruli. Moreover, Th1 and Th17 levels were decreased, while Th2 and Treg levels were increased in the spleen, and the expression of inflammatory cytokines decreased in both the spleen and kidneys. EPO increased Th2 and Treg lymphocytes, decreased Th1, Th17 lymphocytes in the spleen, and inhibited the inflammatory reactions in both the spleen and kidneys, thus ameliorating LN of MRL/lpr mice.

Toll-like receptor 4 shRNA attenuates lipopolysaccharide-induced epithelial-mesenchymal transition of intrahepatic biliary epithelial cells in rats

BACKGROUND AND AIM

Intrahepatic biliary epithelial cells (IBECs) of the bile duct in liver tissue of patients with hepatolithiasis promoted the development of diseases through epithelial-mesenchymal transition (EMT). This study investigated whether lipopolysaccharide (LPS), a cell-wall constituent of gram-negative bacteria, could induce EMT of IBECs and toll-like receptor 4 (TLR4) had a regulatory role via activating the nuclear factor-κB (NF-κB)/Snail signaling pathway during this process in vivo.

METHODS

TLR4 short hairpin RNA (shRNA) adenovirus or negative control shRNA (NC shRNA) adenovirus (1 × 10⁹ plaque-forming unit (PFU), respectively) was injected into the caudal vein of rats. After 96 h, 1 mg/kg LPS was infused retrogradely into the common bile duct for 48 h per rat. The effects of TLR4 shRNA on LPS-induced EMT were determined by evaluating the histopathological changes in IBECs using hematoxylin and eosin staining and the changes in the levels of EMT markers, TLR4, NF-κB p65, pNF-κB p65, and Snail using real-time polymerase chain reaction and Western blot analysis.

RESULTS

Compared with normal saline treatment, a loss of epithelial cell markers (E-cadherin and cytokeratin 7) and a gain of mesenchymal cell markers (N-cadherin and matrix metalloproteinase 2) were revealed. The levels of TLR4, NF-κB phosphorylation, and Snail significantly increased after LPS treatment, whereas pretreatment with TLR4 shRNA inhibited the LPS-induced EMT by downregulating the NF-κB/Snail signaling pathway.

CONCLUSIONS

LPS induced the EMT of IBECs by activating TLR4. The RNAi-mediated knockdown of TLR4 suppressed EMT occurrence via downregulating the NF-κB/Snail signaling pathway, implicating TLR4 as a new target for human hepatolithiasis.

Baicalein alleviates tubular-interstitial nephritis in vivo and in vitro by down-regulating NF-κB and MAPK pathways

Tubular-interstitial nephritis (TIN) is characterized by tubular cell damage and inflammatory lesions of kidneys. Baicalein (BAI) is a flavonoid compound found in the roots of Scutellaria baicalensis Georgi. The present study was undertaken to explore the anti-inflammatory and anti-oxidative effects of BAI on TIN patients and a lipopolysaccharide (LPS)-induced TIN cell model. The expression levels of interleukin-6 (IL-6), IL-10, and tumor necrosis factor α in serum samples of TIN patients and culture supernatants of renal proximal tubular epithelial cells (RPTECs) were evaluated using enzyme-linked immunosorbent assay. Creatinine clearance was calculated using the Cockcroft-Gault equation. Activities of malondialdehyde, superoxide dismutase, and glutathione peroxidase were also determined. Viability and apoptosis of RPTECs were measured using MTT assay and Guava Nexin assay, respectively. qRT-PCR was performed to determine the expressions of Bax, Bcl-2, nuclear factor kappa B (IκBα), and p65. Protein levels of Bax, Bcl-2, IκBα, p65, c-Jun N-terminal kinase, extracellular regulated protein kinases, and p38 were analyzed using western blotting. We found that BAI reduced inflammation and oxidative stress in vivo and in vitro. Moreover, BAI alleviated the LPS-induced RPTECs viability inhibition and apoptosis enhancement, as well as nuclear factor kappa B (NF-κB), and mitogen-activated protein kinase (MAPK) activation. Phorbol ester, an activator of NF-κB, attenuated the effects of BAI on LPS-induced inflammatory cytokine expressions in RPTECs. In conclusion, BAI had anti-inflammatory and anti-oxidative effects on TIN patients and LPS-induced RPTECs by down-regulating NF-κB and MAPK pathways.

The roles of the TLR/NF‑κB signaling pathway in the mutual interactions between the lung and the large intestine

The 'exterior-interior relationship between the lung and the large intestine' is a classical basic theory in Traditional Chinese Medicine. The present study aimed to investigate the roles of the toll like receptor/nuclear factor‑κB (TLR/NF‑κB) signaling pathway in the mutual interactions between the lung and the large intestine. A rat model of allergic asthma complicated with intestinal flora disorder was established by oral administration of Candida albicans and intraperitoneal injection with ovalbumin. The number of inflammatory cells and expression levels immunoglobulin (Ig)E, secretory IgA, interleukin (IL)‑4 and interferon‑γ in serum and bronchoalveolar lavage fluid were subsequently measured. Bacterial colonies and expression of 16S ribosomal DNA were studied in feces samples and pathological alterations of lung tissues were identified. Furthermore, the expression levels of genes associated with the TLR/NF‑κB signaling pathway in the lung and intestinal tissues were determined by reverse transcription‑quantitative polymerase chain reaction. The results of the present study indicated that, in the rat model of allergic asthma complicated with intestinal flora disorder, the expression levels of IL‑4 and IgE, and the numbers of inflammatory cells and C. albicans increased, and marked inflammatory cell infiltration was observed in lung tissues, suggesting that the animal model was successfully established. Furthermore, the present results revealed the mRNA expression levels of genes associated with the TLR/NF‑κB signaling (including myeloid differentiation primary response 88, TNF receptor associated factor 6 and β‑arrestin) were upregulated in both of the lung and intestinal tissues of the model group rats. Collectively, the results demonstrated that the TLR/NF‑κB signaling may serve roles in the mutual interactions between the lung and the large intestine, and TLR and NF‑κB may be potential targets for the treatment of lung diseases complicated with intestinal disorders.

Long non-coding RNA TUG1 protects renal tubular epithelial cells against injury induced by lipopolysaccharide via regulating microRNA-223

BACKGROUND

Lupus nephritis (LN) is a serious complication of systemic lupus erythematosus (SLE). Long non-coding RNA taurine upregulated gene 1 (lncRNA TUG1) exerted critical regulatory effects on inhibiting cell injury and inflammation. However, its role in LN is still unclear.

METHODS

HK-2 cells were treated with lipopolysaccharide (LPS) to simulate cell inflammatory injury. Cell viability and apoptosis, as well as pro-inflammatory factors expression were measured, respectively. Then, HK-2 cells were transfected with pEX-TUG1 or sh-TUG1 to explore the effects of TUG1 on LPS-induced cell injury. Potential binding effects between TUG1 and microRNA-223 (miR-223), as well as between miR-223 and Sirtuin 1 (Sirt1) were verified. miR-223 mimic or miR-223 inhibitor was transfected to assess the effects of miR-223 on cell injury. Finally, the roles of Sirt1 in LPS-induced HK-2 cell injury and activation of phosphatidylinositol 3-kinase/protein kinase 3 (PI3K/AKT) and nuclear factor kappa B (NF-κB) pathways were explored.

RESULTS

LPS administration inhibited HK-2 cell viability and proliferation, increased expression of pro-inflammatory factors, and promoted cell apoptosis. TUG1 overexpression protected HK-2 cells against LPS-induced injury via negatively regulating miR-223 expression. TUG1 suppression had opposite effects. Sirt1 was a direct target gene of miR-223 in HK-2 cells, which participated in the effects of miR-223 on HK-2 cells and was related with the activation of PI3K/AKT and NF-κB pathways.

CONCLUSION

TUG1 protected HK-2 cells against LPS-induced inflammatory injury by regulating miR-223 and Sirt1 expression, and then activating PI3K/AKT and inactivating NF-κB pathways. TUG1 might be a potential therapeutic target for LN treatment.

CSTMP induces apoptosis and mitochondrial dysfunction in human myeloma RPMI8226 cells via CHOP-dependent endoplasmic reticulum stress

BACKGROUND

The natural product tetramethylpyrazine (TMP) and resveratrol have a variety of biologic activities, including anti-cancer effects. However the pharmacological function of CSTMP (a newly designed and synthesized TMP and resveratrol derivative) in cancer have not been elucidated.

METHODS

In RPMI8226 cells, the cytotoxic effects and apoptosis were detected by MTT and Double staining for Annexin V-FITC and propidium iodide (PI). The protein and mRNA expression levels were detected by Real Time PCR and Western blot, respectively. The localization of cleaved caspase-12 was evaluated by immunofluorescent staining. The activation of caspase were measured by colorimetric assays and Western blot.

RESULTS

CSTMP showed significantly cytotoxic effects and induced apoptosis in RPMI8226 cells. Caspase activation, Cytochrome c release and Bax, Bcl-2 and Bcl-XL levels analyses demonstrated that the anti-cancer effect of CSTMP in RPMI8226 cells was mediated by promoting caspase- and mitochondria-dependent apoptosis. In addition, CSTMP induced the increased expression of endoplasmic reticulum (ER) stress related proteins (CHOP, GRP78, GRP94 and cleaved caspase-12) and the activation of multiple branches of ER stress transducers (PERK-eIF2α, IRE1α and ATF6). Moreover, knockdown of CHOP by siRNA markedly inhibited CSTMP-induced cytotoxic effects, caspases activity and mitochondrial dysfunction in RPMI8226 cells.

CONCLUSIONS

Our results indicated that CSTMP could induce apoptosis and mitochondrial dysfunction in RPMI8226 cells via CHOP-dependent ER stress.