Tacrolimus (FK506) inhibits interleukin-1β-induced angiopoietin-1, Tie-2 receptor, and vascular endothelial growth factor through down-regulation of JNK and p38 pathway in human rheumatoid fibroblast-like synoviocytes

Burning down the house: Pyroptosis in the tumor microenvironment of hepatocellular carcinoma

A high mortality rate makes hepatocellular carcinoma (HCC) a difficult cancer to treat. When surgery is not possible, liver cancer patients are treated with chemotherapy. However, HCC management and treatment are difficult. Sorafenib, which is a first-line treatment for hepatocellular carcinoma, initially slows disease progression. However, sorafenib resistance limits patient survival. Recent studies have linked HCC to programmed cell death, which has increased researcher interest in therapies targeting cell death. Pyroptosis, which is an inflammatory mode of programmed cell death, may be targeted to treat HCC. Pyroptosis pathways, executors, and effects are examined in this paper. This review summarizes how pyroptosis affects the tumor microenvironment (TME) in HCC, including the role of cytokines such as IL-1β and IL-18 in regulating immune responses. The use of chemotherapies and their ability to induce cancer cell pyroptosis as alternative treatments and combining them with other drugs to reduce side effects is also discussed. In conclusion, we highlight the potential of inducing pyroptosis to treat HCC and suggest ways to improve patient outcomes. Studies on cancer cell pyroptosis may lead to new HCC treatments.

Advances of the small molecule drugs regulating fibroblast-like synovial proliferation for rheumatoid arthritis

Rheumatoid arthritis (RA) is a type of chronic autoimmune and inflammatory disease. In the pathological process of RA, the alteration of fibroblast-like synoviocyte (FLS) and its related factors is the main influence in the clinic and fundamental research. In RA, FLS exhibits a uniquely aggressive phenotype, leading to synovial hyperplasia, destruction of the cartilage and bone, and a pro-inflammatory environment in the synovial tissue for perpetuation and progression. Evidently, it is a highly promising way to target the pathological function of FLS for new anti-RA drugs. Based on this, we summed up the pathological mechanism of RA-FLS and reviewed the recent progress of small molecule drugs, including the synthetic small molecule compounds and natural products targeting RA-FLS. In the end, there were some views for further action. Compared with MAPK and NF-κB signaling pathways, the JAK/STAT signaling pathway has great potential for research as targets. A small number of synthetic small molecule compounds have entered the clinic to treat RA and are often used in combination with other drugs. Meanwhile, most natural products are currently in the experimental stage, not the clinical trial stage, such as triptolide. There is an urgent need to unremittingly develop new agents for RA.

Membranoproliferative glomerulonephritis after intravitreal vascular growth factor inhibitor injections: A case report and review of the literature

Systemic administration of agents that inhibit vascular endothelial growth factor (VEGF) and therefore vascular proliferation is often used to treat various cancers. However, these agents are associated with a number of side effects, including proteinuria and renal injury. Intravitreal injection of anti-VEGF agents has become the cornerstone of macular disease treatment. Since these agents cross the blood-retina barrier and enter the circulation, systemic side effects have been reported. We report the novel case of a 57-year-old patient who presented with macular oedema secondary to central retinal vein occlusion, underwent three monthly loading-dose injections with the anti-VEGF agent ranibizumab, and 2 weeks after the second injection presented with biopsy-verified membranoproliferative glomerulonephritis. Twelve weeks after presenting with renal failure and 10 weeks after his last anti-VEGF injection, the patient demonstrated spontaneous recovery of his kidney function. The patient had a history that promoted renal fragility, including hypertension, liver transplantation 6 years earlier for alcohol-related cirrhosis and new-onset diabetes mellitus after transplant. Our literature review and case suggest that although adverse renal events after intravitreal anti-VEGF injections are very rare, ophthalmologists and nephrologists should be aware of this risk.

Angiogenesis modulation-mediated inhibitory effects of tacrolimus on hypertrophic scar formation

Hypertrophic scar (HS) is a fibroproliferative disorder that causes cosmetic as well as functional problems; however, to our knowledge, there is no satisfactory treatment for HS to date. Previous studies have indicated that angiogenesis plays a crucial role in HS formation; therefore, anti-angiogenetic therapies are considered effective in improving HS. Although tacrolimus (TAC) has been proven effective in preventing HS formation in vivo and in vitro, its underlying mechanism remains controversial and ambiguous. Because of its anti-angiogenic effects in other diseases, we aimed to determine whether TAC reduces HS by suppressing angiogenesis. Using a rabbit ear HS model that we developed, HS was treated once a week with normal saline, dimethyl sulfoxide, or TAC for 3 weeks. Histological evaluation indicated that TAC significantly reduced collagen deposition and microvessel density in scar tissues. Moreover, immunofluorescence staining for CD31 and vascular endothelial growth factor (VEGF)-A revealed that TAC significantly inhibited HS angiogenesis. In vitro analysis showed that TAC inhibited endothelial cell migration and tubulogenesis as well as the viability and proliferation of human umbilical vascular endothelial cells (HUVECs) and HS fibroblasts (HSFBs). Furthermore, TAC significantly downregulated the expression of the human angiogenetic factors VEGF-A, FGF-2, PDGF-β, and TGF-β1 in HUVECs and HSFBs. Additionally, TAC-mediated inhibition of angiogenesis decreased the gene expression of crucial fibrotic markers, including α- smooth muscle actin and collagens 1 and 3, in HSFBs. This is the first study to demonstrate the inhibitory effects of TAC on HS formation mediated by a mechanism involving the suppression of scar angiogenesis.

IL-33-induced keratoconjunctivitis is mediated by group 2 innate lymphoid cells in mice

BACKGROUND

Interleukin-33 (IL-33) is involved in type 2 innate immunity by inducing type 2 cytokines, such as IL-5 and IL-13, through the activation of group 2 innate lymphoid cells (ILC2s) or T helper 2 (Th2) cells. We previously reported that mice overexpressing IL-33 (IL-33Tg) in the cornea and conjunctiva spontaneously develop atopic keratoconjunctivitis-like inflammation. Despite previous studies, it is not fully understood what types of immune cells contribute to the disease process of IL-33-induced keratoconjunctivitis.

METHODS

To defect Th2 cells, IL-33Tg mice were crossed with Rag2KO mice. To defect ILC2s, IL-33Tg mice received bone marrow transplantations from B6.C3(Cg)-Rorasg/J mice that lacked ILC2. Immunostaining techniques were used to determine where ILC2 is distributed in the cornea and conjunctiva. We analyzed the transcriptomes of ILC2 from the conjunctiva by using single-cell RNA-seq analysis. To investigate whether tacrolimus reduces type 2 cytokine production by ILC2, ILC2 was cultured with tacrolimus, and the percentage of cytokine-producing ILC2 was examined. To investigate whether tacrolimus can inhibit IL-33-induced keratoconjunctivitis in vivo, IL-33Tg mice were treated with tacrolimus eye drops.

RESULTS

ILC2 infiltrated the conjunctival epithelium and subepithelial tissue. Keratoconjunctivitis developed spontaneously in Rag2KO/IL-33Tg mice, but keratoconjunctivitis was abolished in IL-33Tg mice lacking ILC2. ILC2 was not a uniform cluster but a heterogeneous cluster. Tacrolimus inhibited cytokine production from ILC2s in vitro, and tacrolimus eye drops inhibited keratoconjunctivitis in IL-33Tg mice in vivo.

CONCLUSIONS

ILC2 plays a pivotal role in IL-33-induced keratoconjunctivitis in mice.

Imperatorin Inhibits Proliferation, Migration, and Inflammation via Blocking the NF-κB and MAPK Pathways in Rheumatoid Fibroblast-like Synoviocytes

Rheumatoid arthritis (RA) is a chronic joint inflammatory disease associated with the aberrant activation of fibroblast-like synoviocytes (FLSs). Searching for natural compounds that may suppress the activation of FLSs has become a complementary approach for RA treatment. Here, we investigated the effects and mechanisms of imperatorin (IPT) on proliferation, migration, and inflammation in primary cultured arthritic FLSs. We found that IPT significantly suppressed TNFα-induced proliferation and migration of arthritic FLSs, but showed little effect on survival and apoptosis. In addition, IPT treatment significantly reduced the TNFα-induced expression of pro-inflammatory cytokines (IL-1β, TNFα, IL-6, and IL-8) in arthritic FLSs. Further mechanism studies suggested that IPT inhibited the activations of p38 and extracellular signal-regulated kinase (ERK). Also, IPT blocked the nuclear factor of κB (NF-κB) activation by suppressing the phosphorylation and degradation of IκBα, thereby preventing the translocation of p65. Collectively, our results demonstrated that IPT could inhibit the over-activated phenotypes of arthritic FLSs via the mitogen-activated protein kinase (MAPK) (p38 and ERK) and NF-κB pathways leading to the down-regulation of pro-inflammatory cytokines, which might be beneficial to the anti-proliferative and anti-migratory activities of FLS cells. These findings suggest that IPT has the potential to be developed as a novel agent for RA treatment.

Peimine suppresses collagen-induced arthritis, activated fibroblast-like synoviocytes and TNFα-induced MAPK pathways

BACKGROUND AND PURPOSE

Peimine (PM), a main isosterol alkaloid component isolated from the bulbs of traditional Chinese herb Fritillaria cirrhosa D. Don, has been demonstrated to exhibit multiple pharmacological properties, including anti-inflammation, anti-cancer and pain suppression. However, its effect on rheumatoid arthritis (RA) remains unknown. In the present study, we investigated the effect of PM on collagen-induced arthritis (CIA) rats in vivo and its inhibition on destructive behaviors of arthritic fibroblast-like synoviocytes (FLSs) in vitro.

METHODS

Arthritis was induced in rats by chicken type II collagen. Arthritis score, radiological evaluation, and histopathological assessment were used to evaluate the therapeutic effects of PM on CIA rats. EdU assay, wound healing assay and real-time PCR were used to examine the inhibitory effect of PM on proliferation, migration, and over-expression of pro-inflammatory cytokines in TNFα-induced arthritic FLSs. TRAP staining and scanning electron microscopy were used to analyze the effect of PM on osteoclastogensis and bone resorption. Western blot was used to reveal PM's molecular mechanism of action on RA.

RESULTS

PM significantly suppressed synovitis and bone destruction in CIA rats. In vitro experiments showed that PM treatment significantly inhibited TNFα-induced destructive behaviors of arthritic FLSs, including over-proliferation, migration and over-expression of pro-inflammatory cytokines. Additionally, RANKL-induced osteoclast formation and bone-resorpting function were also inhibited by PM. Further molecular mechanism studies revealed that PM treatment significantly suppressed TNFα-induced activations of MAPKs (ERK, JNK and p38) in arthritic FLSs.

CONCLUSION

Our findings provide strong evidence that PM has the potential to be developed as a therapeutic agent for patients with RA.

Mangiferin exert protective effects on joints of adjuvant-induced arthritis rats by regulating the MAPKs/NF-κB pathway of fibroblast-like synoviocytes

BACKGROUND

Mangiferin (MF) is a bioactive ingredient predominantly isolated from the mango tree, that has been reported to have antioxidant, anti-inflammatory, and immunomodulatory effects. This study was aimed to investigate the protective effect of MF on the joints of arthritic rats and explore the underlying mechanisms of this function.

METHODS

Adjuvant-induced arthritis (AA) rat model was established and clinical severity of AA was evaluated by arthritis index, paw edema, plasma, and synovium homogenate parameters. The severity of joint destruction was assessed by radiological and histopathological. Immunohistochemical analysis was employed to detect the protein expression of MMP-3, MMP-13 in synovium and cartilage tissues. The vitro effects of MF on proliferation, migration, apoptosis, and production of inflammatory mediators in RA- FLSs were determined by the CCK8 assay, transwell assay, flow cytometry, and real-time PCR, respectively.

RESULTS

The results demonstrated that MF treatment significantly alleviated arthritis index, paw swelling and decreased the secretion of inflammatory cytokines in plasma and synovium. Meanwhile, MF inhibited synovial inflammation, pannus formation, and bone erosion in AA rats. It also ameliorated the oxidative stress state of arthritic rats via modulating the level of MDA, SOD, CAT, GSH, NO. In addition, MF effectively attenuated the destructive behavior of RA-FLSs by inhibiting proliferation, migration, and secretion of inflammatory mediators, and promoting apoptosis. The further mechanistic analysis demonstrated that MF might exert an antiarthritic effect via inhibiting the pathway of MAPKs (ERK2 and p38) and NF-κ B.

CONCLUSION

Taken together, our results demonstrated that MF would be a promising anti-arthritic agent candidate for further research.

Matrine inhibits synovial angiogenesis in collagen-induced arthritis rats by regulating HIF-VEGF-Ang and inhibiting the PI3K/Akt signaling pathway

Matrine (Mat) is an alkaloid of tetracycline quinazine, and previous studies have demonstrated its specific effect on relieving rheumatoid arthritis (RA). However, the effect of Mat on joint synovial angiogenesis in the pathogenesis of RA has not been elucidated. In this study, body weight, joint swelling, arthritis index (AI) score, histopathological changes, immunohistochemical, and western blot- were used in collagen-induced arthritis (CIA) rats to detect pro-inflammatory factors and, - expression levels of key cytokines and proteins along the hypoxia-inducible factor (HIF)-endothelial growth factor (VEGF)-angiopoietin (Ang) axis and VEGF-phosphoinositide 3-kinase (PI3K) / protein kinase B (Akt) pathway. In vitro experiments were conducted to observe the effect of Mat on the proliferation, migration and lumen formation of RA-fibroblast-like synovial cells (FLS) and human umbilical vein endothelial cells (HUVECs). Results showed that Mat reduced the degree of paw swelling and AI score in CIA rats, joint synovial tissue proliferation, inflammatory cell infiltration, and neovascularization; moreover, it down-regulated the expression levels of inflammatory factors interleukin-1β, interferon-γ, and pro-angiogenic factors VEGF, placental growth factor, HIF-α, Ang-1, Ang-2, Tie-2, and phosphorylation-Akt in the ankle joint of CIA rats. In addition, the in vitro experiments showed that Mat inhibited the proliferation and migration of RA-FLS and inhibited the proliferation and lumen formation of HUVECs. Therefore, Mat exerts an anti-angiogenesis effect by regulating the HIF-VEGF-Ang axis and inhibiting the PI3K/Akt signaling pathway. This inhibits the pathogenesis and improve the symptoms of RA, and may be offered as a candidate drug for the treatment of RA.

The role of microenvironment in tumor angiogenesis

Tumor angiogenesis is necessary for the continued survival and development of tumor cells, and plays an important role in their growth, invasion, and metastasis. The tumor microenvironment—composed of tumor cells, surrounding cells, and secreted cytokines—provides a conducive environment for the growth and survival of tumors. Different components of the tumor microenvironment can regulate tumor development. In this review, we have discussed the regulatory role of the microenvironment in tumor angiogenesis. High expression of angiogenic factors and inflammatory cytokines in the tumor microenvironment, as well as hypoxia, are presumed to be the reasons for poor therapeutic efficacy of current anti-angiogenic drugs. A combination of anti-angiogenic drugs and antitumor inflammatory drugs or hypoxia inhibitors might improve the therapeutic outcome.

Elevated plasma tyrosine kinases VEGF-D and HER4 in heart failure patients decrease after heart transplantation in association with improved haemodynamics

Receptor tyrosine kinases (RTKs) are implicated in cardiovascular growth and remodelling. We aimed to identify the plasma levels of RTKs and related proteins and their association with haemodynamic alterations in heart failure (HF) and related pulmonary hypertension (PH) following heart transplantation (HT). Using proximity extension assay, 28 RTKs and related proteins were analysed in plasma from 20 healthy controls and 26 HF patients before and 1-year after HT. In end-stage HF, out of 28 RTKs, plasma vascular endothelial growth factor-D (VEGF-D) and human epidermal growth factor-4 (HER4) were elevated compared to controls (p < 0.001), but decreased (p < 0.0001) and normalised after HT. Following HT, plasma changes (Δ) of VEGF-D correlated with Δmean pulmonary artery pressure (rs = 0.65, p = 0.00049), Δpulmonary artery wedge pressure (rs = 0.72, p < 0.0001), Δpulmonary arterial compliance (PAC) (rs = - 0.52, p = 0.0083) and Δpulmonary vascular resistance (PVR) (rs = 0.58, p = 0.0032). ΔHER4 correlated with Δmean right atrial pressure (rs = 0.51, p = 0.012), ΔNT-proBNP (rs = 0.48, p = 0.016) and Δcardiac index (rs = - 0.56, p = 0.0044). In HF patients following HT, normalisation of VEGF-D reflected reversal of passive pulmonary congestion and restored PAC and PVR; whereas the normalisation of HER4 reflected decreased volume overload and improved cardiac function. The precise function of these proteins, their potential clinical use and pathophysiological relation in HF and related PH remain to be elucidated.

Monocyte chemoattractant protein‑1 promotes the proliferation, migration and differentiation potential of fibroblast‑like synoviocytes via the PI3K/P38 cellular signaling pathway

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the joints and joint destruction. Monocyte chemoattractant protein 1 (MCP‑1) is highly expressed in the joints of patients suffering from RA. The present study aimed to evaluate the effects of MCP‑1 on the phenotype of fibroblast‑like synoviocytes (FLSs) and their differentiation potential towards vascular endothelial cells. The expression of MCP‑1 in collagen‑induced arthritis (CIA) rats was investigated by PCR, ELISA and immunohistology. Cell proliferation induced by MCP‑1 was measured using a Cell Counting Kit‑8 (CCK‑8) and 5‑Bromo‑2‑deoxyuridine ELISA assay. In addition, the effects of MCP‑1 on the migration of FLSs was examined using a Transwell assay. Activation of PI3K and P38 were investigated by western blotting following MCP‑1 treatment. The vascular endothelial cell markers, tumor necrosis factor alpha (TNF‑α) and interleukin‑1 beta (IL‑β), were also examined by western blotting. LY294002 [PI3K inhibitor, (LY)] and SB203580 [P38 inhibitor, (SB)] were used to examine the proliferative and pro‑differentiation effect of PI3K and P38. The present findings showed that the expression level of MCP‑1 in the synovium of CIA rats was significantly higher compared with controls. The present in vitro study suggested that MCP‑1 increased the FLSs cell numbers with a maximal effect at 200 ng/ml, and induced the maximal phosphorylation of PI3K at 15 min and P38 at 30 min. In addition, MCP‑1 stimulation significantly increased the migration of FLSs. Furthermore, MCP‑1‑induced the expression of vascular endothelial growth factor and CD31 in FLSs. Suppression of PI3K and P38 was found to reduce MCP‑1 induced FLSs proliferation and migration, and decreased the expression levels of angiogenesis markers increased following MCP‑1 treatment. MCP‑1 was also found to increase the expression levels of both TNF‑α and IL‑β. Therefore, MCP‑1 could promote the proliferation and migration of FLSs, and was found to increase the expression levels of various angiogenesis markers via PI3K/P38, suggesting a role for this pathway in synovium hyperplasia in RA.

Pedunculoside attenuates pathological phenotypes of fibroblast-like synoviocytes and protects against collagen-induced arthritis

Objectives: The discovery of alternative and well-tolerated anti-arthritic drugs, especially from natural products, is becoming an area of active research. Pedunculoside (PE) is a novel triterpene saponin extracted from the dried bark of Ilex rotunda Thunb. Limited published papers have reported its pharmacological properties, including anti-inflammatory, anti-myocardial ischaemia, anti-liver injury, and hypocholesterolaemic activities. However, the effect of PE on rheumatoid arthritis (RA) remains unknown. Here, we investigated the anti-arthritic effect of PE in both in vitro and in vivo models. Method: The inhibitory effects of PE on proliferation, migration, and production of inflammatory mediators in primary fibroblast-like synoviocytes (FLSs) were examined by a 5-ethynyl-2'-deoxyuridine incorporation assay, wound-healing assay, and real-time polymerase chain reaction, respectively. Cellular signalling mechanisms were analysed by Western blot. The in vivo studies were performed using a collagen-induced arthritis (CIA) rat model. Multiple methods, including arthritis scoring, enzyme-linked immunoassay, radiography, and histopathological assessment, were used to evaluate the therapeutic effects of PE on CIA rats. Results: The in vitro studies revealed that PE significantly inhibited proliferation and migration of FLSs. PE also decreased the production of pro-inflammatory cytokines, including interleukin-1β (IL-1β), IL-6, IL-8, and tumour necrosis factor-α (TNF-α). Western blot results suggested that PE suppressed TNF-α-stimulated activation of p38 and extracellular signal-regulated kinase. The in vivo studies showed that PE treatment significantly inhibited synovial inflammation and bone destruction in CIA rats. Conclusion: These results demonstrate that PE exerts an inhibitory role in FLSs and CIA rats, and therefore may have therapeutic value for the treatment of RA.

IL-1 Family Cytokine Regulation of Vascular Permeability and Angiogenesis

The IL-1 family of cytokines are well-known for their primary role in initiating inflammatory responses both in response to and acting as danger signals. It has long been established that IL-1 is capable of simultaneously regulating inflammation and angiogenesis, indeed one of IL-1's earliest names was haemopoeitn-1 due to its pro-angiogenic effects. Other IL-1 family cytokines are also known to have roles in mediating angiogenesis, either directly or indirectly via induction of proangiogenic factors such as VEGF. Of note, some of these family members appear to have directly opposing effects in different tissues and pathologies. Here we will review what is known about how the various IL-1 family members regulate vascular permeability and angiogenic function in a range of different tissues, and describe some of the mechanisms employed to achieve these effects.

Simiao Pill Attenuates Collagen-Induced Arthritis in Rats through Suppressing the ATX-LPA and MAPK Signalling Pathways

Objective

Simiao pill (SM), a traditional Chinese formula, has been used as an antirheumatic drug in clinical practice for hundreds of years. Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation and hyperplasia, cartilage destruction, and joint damage. This study was designed to investigate the protective effects of SM on collagen-induced arthritis (CIA) in rats. It also aimed to explore whether this protective effect of SM was related to the inhibition of the ATX-LPA and MAPK signalling pathways.

Materials and Methods

Rats were injected with a collagen II emulsion at the end of the tail and on the back to induce arthritis. Treatment with different doses of SM was conducted by intragastric administration. Then, body weights and arthritis scores were measured. The serum levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, C-reactive protein (CRP), osteoprotegerin (OPG), autotaxin (ATX), and lysophosphatidic acid (LPA) were determined by ELISA. Pathological changes in the joints were measured by micro-CT and assessed via haematoxylin-eosin (H&E) staining. The expression of ATX, LPA receptor 1 (LPA1) was detected by immunohistochemical staining, and the expression of mitogen-activated protein kinase (MAPK) was detected by Western blotting.

Results

SM significantly alleviated arthritis symptoms, inhibited bone erosion, and decreased the levels of TNF-α, IL-1β, CRP, ATX, and LPA in the sera of CIA rats. Importantly, SM clearly reduced the protein expression of LPA1 and ATX. The activation of the MAPK signalling pathway was also inhibited by SM in the synovial tissues of CIA rats.

Conclusions

The antirheumatic effects of SM were associated with the regulation of the ATX-LPA and MAPK pathways, the suppression of proinflammatory cytokine production, and the alleviation of cartilage and bone injury. These findings suggest that SM might be a promising alternative candidate for RA therapy.

Jatrorrhizine Hydrochloride Suppresses Proliferation, Migration, and Secretion of Synoviocytes In Vitro and Ameliorates Rat Models of Rheumatoid Arthritis In Vivo

Jatrorrhizine hydrochloride (JH), an active component isolated from the traditional Chinese herb Coptis chinensis, has been reported to have antimicrobial, antitumor, antihypercholesterolemic, and neuroprotective activities. However, its antirheumatoid arthritis (RA) property remains unknown. In this study, a collagen-induced arthritis (CIA) rat model was used to evaluate the therapeutic effects of JH on RA by using arthritis score, radiological evaluation, and histopathological assessment. The in vitro effects of JH on proliferation, migration, and production of inflammatory mediators in RA-derived fibroblast-like synoviocyte MH7A cells were determined by the EdU incorporation assay, wound healing assay, real-time PCR, and ELISA, respectively. The in vivo studies showed that JH treatment significantly prevented the progression and development of RA in CIA rats through anti-inflammation and suppressing bone destruction. The in vitro studies revealed that JH could effectively attenuate the destructive phenotypes of MH7A cells, including inhibiting proliferation, migration, and production of inflammatory mediators. Further mechanistic analysis demonstrated that JH suppressed tumor necrosis factor alpha (TNFα)-stimulated activations of nuclear factor of kappaB (NF-κB) and mitogen-activated protein kinases (MAPKs) (ERK and p38) leading to the downregulation of proinflammatory cytokines, which might be beneficial to the antiproliferative and antimigratory activities of FLS cells. Collectively, our results demonstrated that JH has a great potential to be developed into a novel therapeutic agent for treating RA.

Tacrolimus regulates endoplasmic reticulum stress-mediated osteoclastogenesis and inflammation: In vitro and collagen-induced arthritis mouse model

Tacrolimus is an immunosuppressive drug that inhibits the release of inflammatory cytokines involved in rheumatoid arthritis development by blocking T cell activation. "Endoplasmic reticulum stress," an imbalance between protein folding load and capacity leading to the accumulation of unfolded proteins in the endoplasmic reticulum lumen, has been implicated in rheumatoid arthritis and other inflammatory and metabolic diseases. We aimed to investigate the effect of tacrolimus on endoplasmic reticulum stress-mediated osteoclastogenesis and inflammation and elucidate the underlying mechanisms. In vitro studies were performed using mouse bone marrow cells that were cultured with or without interleukin-1β, thapsigargin, or tacrolimus to induce osteoclast differentiation. A mouse model of arthritis was established by immunizing mice with bovine type II collagen. Tacrolimus was orally administered to mice from day 20 to 45 following the initial immunization, and histopathological changes and expression of specific biomarkers of endoplasmic reticulum stress-mediated inflammatory signaling pathways were examined. In vitro, tacrolimus inhibited receptor activator of nuclear factor-κB ligand-mediated osteoclast formation augmented by interleukin-1β, thapsigargin, or both. Furthermore, tacrolimus inhibited glucose-regulated protein (GRP78), protein kinase R-like endoplasmic reticulum kinase, inositol-requiring enzyme 1 (IRE 1), and activating transcription factor 6 (ATF6) augmented by interleukin-1β, thapsigargin, or both. Tacrolimus significantly ameliorated osteolysis and endoplasmic reticulum stress intensity in mice. Simultaneously, it reduced inflammatory cell infiltration, osteoclastogenesis, and inflammatory responses by inhibiting GRP78, IRE 1, and ATF6. These findings suggest that tacrolimus exhibits an anti-inflammation effect in rheumatoid arthritis and might inhibit joint damage progression by inhibiting endoplasmic reticulum stress.

Tumor necrosis factor-α levels and non-surgical bleeding in continuous-flow left ventricular assist devices

BACKGROUND

Non-surgical bleeding (NSB) due to angiodysplasia is common in left ventricular assist device (LVAD) patients. Thrombin-induced angiopoietin-2 (Ang-2) expression in LVAD patients leads to altered angiogenesis and is associated with lower angiopoietin-1 (Ang-1) and increased NSB. However, the mechanism for decreased Ang-1, made by pericytes, is unknown and the origin of thrombin in LVAD patients is unclear. We hypothesized that high tumor necrosis factor-α (TNF-α) levels in LVAD patients induce pericyte apoptosis, tissue factor (TF) expression and vascular instability.

METHODS

We incubated cultured pericytes with serum from patients with heart failure (HF), LVAD or orthotopic heart transplantation (OHT), with or without TNF-α blockade. We performed several measurements: Ang-1 expression was assessed by reverse transcript-polymerase chain reaction (RT-PCR) and pericyte death fluorescently; TF expression was assessed by RT-PCR in cultured endothelial cells incubated with patient plasma with or without TNF-α blockade; and TF expression was assessed in endothelial biopsy samples from these patients by immunofluorescence. We incubated cultured endothelial cells on Matrigel with patient serum with or without TNF-α blockade and determined tube formation by microscopy.

RESULTS

Serum from LVAD patients had higher levels of TNF-α, suppressed Ang-1 expression in pericytes, and induced pericyte death, and there was accelerated endothelial tube formation compared with serum from patients without LVADs. TF was higher in both plasma and endothelial cells from LVAD patients, and plasma from LVAD patients induced more endothelial TF expression. All of these effects were reversed or reduced with TNF-α blockade. High levels of TNF-α were associated with increased risk of NSB.

CONCLUSIONS

Elevated TNF-α in LVAD patients is a central regulator of altered angiogenesis, pericyte apoptosis and expression of TF and Ang-1.

Calcineurin inhibitors cyclosporin A and tacrolimus protect against podocyte injury induced by puromycin aminonucleoside in rodent models

Podocyte injury and the appearance of proteinuria are features of minimal-change disease (MCD). Cyclosporin A (CsA) and tacrolimus (FK506) has been reported to reduce proteinuria in patients with nephrotic syndrome, but mechanisms remain unknown. We, therefore, investigated the protective mechanisms of CsA and FK506 on proteinuria in a rat model of MCD induced by puromycin aminonucleoside (PAN) and in vitro cultured mouse podocytes. Our results showed that CsA and FK506 treatment decreased proteinuria via a mechanism associated to a reduction in the foot-process fusion and desmin, and a recovery of synaptopodin and podocin. In PAN-treated mouse podocytes, pre-incubation with CsA and FK506 restored the distribution of the actin cytoskeleton, increased the expression of synaptopodin and podocin, improved podocyte viability, and reduced the migrating activities of podocytes. Treatment with CsA and FK506 also inhibited PAN-induced podocytes apoptosis, which was associated with the induction of Bcl-xL and inhibition of Bax, cleaved caspase 3, and cleaved PARP expression. Further studies revealed that CsA and FK506 inhibited PAN-induced p38 and JNK signaling, thereby protecting podocytes from PAN-induced injury. In conclusion, CsA and FK506 inhibit proteinuria by protecting against PAN-induced podocyte injury, which may be associated with inhibition of the MAPK signaling pathway.

Elevated Angiopoietin-2 Level in Patients With Continuous-Flow Left Ventricular Assist Devices Leads to Altered Angiogenesis and Is Associated With Higher Nonsurgical Bleeding

BACKGROUND

Nonsurgical bleeding is the most common adverse event in patients with continuous-flow left ventricular assist devices (LVADs) and is caused by arteriovenous malformations. We hypothesized that deregulation of an angiogenic factor, angiopoietin-2 (Ang-2), in patients with LVADs leads to increased angiogenesis and higher nonsurgical bleeding.

METHODS

Ang-2 and thrombin levels were measured by ELISA and Western blotting, respectively, in blood samples from 101 patients with heart failure, LVAD, or orthotopic heart transplantation. Ang-2 expression in endothelial biopsy was quantified by immunofluorescence. Angiogenesis was determined by in vitro tube formation from serum from each patient with or without Ang-2-blocking antibody. Ang-2 gene expression was measured by reverse transcription-polymerase chain reaction in endothelial cells incubated with plasma from each patient with or without the thrombin receptor blocker vorapaxar.

RESULTS

Compared with patients with heart failure or those with orthotopic heart transplantation, serum levels and endothelial expression of Ang-2 were higher in LVAD patients (P=0.001 and P<0.001, respectively). This corresponded to an increased angiogenic potential of serum from patients with LVADs (P<0.001), which was normalized with Ang-2 blockade. Furthermore, plasma from LVAD patients contained higher amounts of thrombin (P=0.003), which was associated with activation of the contact coagulation system. Plasma from LVAD patients induced more Ang-2 gene expression in endothelial cells (P<0.001), which was reduced with thrombin receptor blockade (P=0.013). LVAD patients with Ang-2 levels above the mean (12.32 ng/mL) had more nonsurgical bleeding events compared with patients with Ang-2 levels below the mean (P=0.003).

CONCLUSIONS

Our findings indicate that thrombin-induced Ang-2 expression in LVAD patients leads to increased angiogenesis in vitro and may be associated with higher nonsurgical bleeding events. Ang-2 therefore may contribute to arteriovenous malformation formation and subsequent bleeding in LVAD patients.

Gq-Coupled Receptors in Autoimmunity

Heterotrimeric G proteins can be divided into Gi, Gs, Gq/11, and G12/13 subfamilies according to their α subunits. The main function of G proteins is transducing signals from G protein coupled receptors (GPCRs), a family of seven transmembrane receptors. In recent years, studies have demonstrated that GPCRs interact with Gq, a member of the Gq/11 subfamily of G proteins. This interaction facilitates the vital role of this family of proteins in immune regulation and autoimmunity, particularly for Gαq, which is considered the functional α subunit of Gq protein. Therefore, understanding the mechanisms through which Gq-coupled receptors control autoreactive lymphocytes is critical and may provide insights into the treatment of autoimmune disorders. In this review, we summarize recent advances in studies of the role of Gq-coupled receptors in autoimmunity, with a focus on their pathologic role and downstream signaling.

IL-1β-regulating angiogenic factors expression in perforated temporomandibular disk cells via NF-κB pathway

BACKGROUND

A high density of blood vessels is observed in the perforated disks of temporomandibular joint (TMJ), but the underlying mechanism is unknown. This study aimed to explore the regulation of disk angiogenesis in the perforated disks.

METHODS

Expressions of vascular endothelial growth factor (VEGF), angiogenin-1 (Ang-1), chondromodulin-1 (ChM-1), and thrombospondins-1 (TSP-1) were compared between healthy and perforated TMJ disk cells with or without interleukin-1β (IL-1β) incubation. The tube formation, cell migration, and expressions of matrix-metalloproteinases (MMPs) in human umbilical vein endothelial cell line (HUV-EC-C) were investigated in conditional media of disk cells. Western blot was performed to determine protein level of VEGF, Ang-1, ChM-1 and TSP-1 in IL-1β-induced disk cells cultured by NF-κB- or P38-specific pathway inhibitors, respectively.

RESULTS

Conditional media from perforated disk cells induced more tube formation, cell migration, and MMPs' expression in HUV-EC-C. Expressions of VEGF and Ang-1 were significantly higher, and ChM-1 and TSP-1 were lower in perforated disks compared to healthy disks. The VEGFA concentration was 291.1 ± 36.09 pg/ml in perforated disk cell conditioned media, markedly larger than that in NDCCM (144.9 ± 33.69 pg/ml). IL-1β induced VEGF through NF-κB signaling pathway and Ang-1 through p38 MAPK pathway, while repressed expression of ChM-1 and TSP-1 was through NF-κB pathway. Blockade of each pathway markedly restrained inducing effect of cultural media on HUV-EC-C tube formation and migration.

CONCLUSIONS

Perforated disk cells secreted more angiogenic factors which might induced via NF-κB pathway.

Targeting of proangiogenic signalling pathways in chronic inflammation

Angiogenesis is de novo capillary outgrowth from pre-existing blood vessels. This process not only is crucial for normal development, but also has an important role in supplying oxygen and nutrients to inflamed tissues, as well as in facilitating the migration of inflammatory cells to the synovium in rheumatoid arthritis, spondyloarthritis and other systemic autoimmune diseases. Neovascularization is dependent on the balance of proangiogenic and antiangiogenic mediators, including growth factors, cytokines, chemokines, cell adhesion molecules and matrix metalloproteinases. This Review describes the various intracellular signalling pathways that govern these angiogenic processes and discusses potential approaches to interfere with pathological angiogenesis, and thereby ameliorate inflammatory disease, by targeting these pathways.

The pathogenic role of angiogenesis in rheumatoid arthritis

Angiogenesis is the formation of new capillaries from pre-existing vasculature, which plays a critical role in the pathogenesis of several inflammatory autoimmune diseases such as rheumatoid arthritis (RA), spondyloarthropathies, psoriasis, systemic lupus erythematosus, systemic sclerosis, and atherosclerosis. In RA, excessive migration of circulating leukocytes into the inflamed joint necessitates formation of new blood vessels to provide nutrients and oxygen to the hypertrophic joint. The dominance of the pro-angiogenic factors over the endogenous angiostatic mediators triggers angiogenesis. In this review article, we highlight the underlying mechanisms by which cells present in the RA synovial tissue are modulated to secrete pro-angiogenic factors. We focus on the significance of pro-angiogenic factors such as growth factors, hypoxia-inducible factors, cytokines, chemokines, matrix metalloproteinases, and adhesion molecules on RA pathogenesis. As pro-angiogenic factors are primarily produced from RA synovial tissue macrophages and fibroblasts, we emphasize the key role of RA synovial tissue lining layer in maintaining synovitis through neovascularization. Lastly, we summarize the specific approaches utilized to target angiogenesis. We conclude that the formation of new blood vessels plays an indispensable role in RA progression. However, since the function of several pro-angiogenic mediators is cross regulated, discovering novel approaches to target multiple cascades or selecting an upstream cascade that impairs the activity of a number of pro-angiogenic factors may provide a promising strategy for RA therapy.

Selective modulation of MAPKs contribute to the anti-proliferative and anti-inflammatory activities of 1,7-dihydroxy-3,4-dimethoxyxanthone in rheumatoid arthritis-derived fibroblast-like synoviocyte MH7A cells

ETHNOPHARMACOLOGICAL RELEVANCE

1,7-Dihydroxy-3,4-dimethoxyxanthone (XAN) is an antirheumatic agent isolated from traditional Chinese medicine Securidaca inappendiculata Hassk. This study was designed to investigate its anti-proliferative and anti-inflammatory activities on rheumatoid arthritis derived fibroblast-like synoviocyte cell line MH7A, and explore the underlying mechanism of action.

METHODS

The anti-proliferative activity of XAN on MH7A cells was assessed by an MTT method. Its pro-apoptotic and cell cycle arrest activities were analyzed by flow cytometry. W-B method was employed to investigate hallmark kinases involved in the course. Pro-inflammatory cytokines in culture supernatant of MH7A cells were determined by an ELISA method.

RESULTS

The results showed XAN efficiently suppressed the proliferation and secretion of IL-1β and IL-6 of MH7A cells in a concentration-dependent manner. Co-treatment with MAPKs inhibitors U0126, SB202190 and SP600125 indicated JNK and p38 pathways were involved in the course. Up-regulation of p-p38, p-ERK, bax and p21, and down-regulation of p-JNK, cyclin D1 and bcl-2 were observed upon the treatment with XAN. SB202190 partly reversed the modulatory effects. The results suggested XAN inhibited the proliferation of MH7A cells mainly via cell cycle arrest at G1/S phase, and the activity was due to the up-regulation of p-p38, which led to the modulation of p21 and cyclin D1. The down-regulation of p-JNK by XAN suppressed the secretion of pro-inflammatory cytokines, which was beneficial to the anti-proliferative activity of MH7A cells.

CONCLUSION

XAN selectively modulated MAPKs signaling, and exerted the subsequent anti-proliferative and anti-inflammatory activities on MH7A cells.

Paeoniflorin regulates the function of human peripheral blood mononuclear cells stimulated by rhIL-1β by up-regulating Treg expression

The aim of the present study was to investigate the effect of paeoniflorin (Pae) on recombinant human interleukin-1β (rhIL-1β)-stimulated human peripheral blood mononuclear cells (PBMCs) in vitro. PBMCs were collected by Ficoll density gradient centrifugation and were co-cultured with rhIL-1β for different time periods. The proliferation response was determined by a cell counting kit-8 (CCK-8) assay. The production of IL-17 and IL-10 was measured by enzyme-linked immunosorbent assay (ELISA). The percentage of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) was detected by flow cytometry analysis. These results indicated that rhIL-1β stimulation induced the proliferation of PBMCs in a concentration- and time-dependent manner; it also increased the level of IL-17 and decreased the level of IL-10 in a concentration-dependent manner. The flow cytometry analysis demonstrated that the stimulation of rhIL-1β significantly downregulated the percentage of CD4(+)CD25(+)Foxp3(+) Treg in CD4(+) T cells. However, administration of Pae significantly suppressed the proliferation response of rhIL-1β-induced PBMCs and regulated the secretion function of IL-17 and IL-10. Additional experiments demonstrated that Pae treatment significantly reduced rhIL-1β-induced decreases in PBMCs CD4(+)CD25(+)Foxp3(+) subpopulation numbers. These results suggest that the anti-inflammatory action of Pae is attributable to its regulation of IL-17/IL-10 secretion and Treg expression.

(S)-1-α-naphthylmethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (CKD712), promotes wound closure by producing VEGF through HO-1 induction in human dermal fibroblasts and mouse skin

BACKGROUND AND PURPOSE

Given the importance of VEGF and haem oxygenase (HO)-1 in wound healing, the present study tested the hypothesis that CKD712, a synthetic tetrahydroisoquinoline alkaloid, activated VEGF production through the induction of HO-1 in human dermal fibroblasts (HDFs) and in mouse skin to stimulate wound healing.

EXPERIMENTAL APPROACH

Using HDFs, the effects of CKD712 on the production of VEGF and migration were evaluated. The mechanisms responsible were investigated using various signal inhibitors and small interfering RNA techniques. The ability of CKD712 to promote wound healing was also investigated in full-thickness skin-wounded mice.

KEY RESULTS

CKD712 treatment of HDFs increased VEGF production and accelerated migration, which was antagonized by anti-VEGF antibodies. Both an AMPK inhibitor (compound C) and a HO-1 activity inhibitor (SnPPIX) but not inhibitors of MAPKs, PI3K and PKC reduced the production of VEGF by CKD712. Interestingly, SnPPIX inhibited HO-1 expression but not p-AMPK, whereas compound C inhibited both p-AMPK and HO-1 induction by CKD712. Moreover, CKD712 decreased HO-1 expression without affecting the expression of p-AMPK by siHO-1 transfection, but it failed to induce HO-1 in siAMPKα1-transfected cells, suggesting that AMPK is involved in HO-1 induction by CKD712 in HDFs. Also, CKD712 shortened the time of wound closure in an SnPPIX-sensitive manner in a full-thickness skin-wounded mouse model.

CONCLUSION AND IMPLICATIONS

CKD712 accelerated cutaneous wound healing, at least in part, by the production of VEGF through HO-1 induction in HDFs and mouse skin.