Neogambogic Acid Suppresses Receptor Activator of Nuclear Factor κB Ligand (RANKL)-Induced Osteoclastogenesis by Inhibiting the JNK and NF-κB Pathways in Mouse Bone Marrow-Derived Monocyte/Macrophages

Neogambogic acid enhances anti-PD-1 immunotherapy efficacy by attenuating suppressive function of MDSCs in pancreatic cancer

BACKGROUND

Anti-PD-1-based immunotherapy has limited benefits in patients with pancreatic cancer. Accumulating data indicate that natural products exert antitumor activity by remodeling the tumor immune microenvironment. It has been reported that neogambogic acid (NGA), an active natural monomer extracted from Garcinia, has anti-inflammatory and antitumor effects. Nevertheless, there are few systematic studies on the antitumor efficacy and immunomodulatory effects of NGA in pancreatic cancer.

METHODS

An orthotopic mouse model of pancreatic cancer was established and were treated with different doses of NGA. Tumor growth and ascites were observed. Flow cytometry and immunohistochemistry (IHC) were used to investigate the tumor immune microenvironment. CD11b+ MDSCs were infused back into mice with pancreatic cancer to observe tumor progression after NGA treatment. Bone marrow cells were induced to differentiate into MDSCs, and the effects of NGA on MDSCs were analyzed and the underlying mechanism was explored. The effects of NGA combined with an anti-PD-1 antibody on pancreatic cancer were further tested.

RESULTS

NGA significantly inhibited the tumor growth and improve ascites character in pancreatic cancer model mice. Flow cytometry and IHC analysis revealed that NGA decreased the MDSCs proportion and infiltration in the tumor microenvironment. Moreover, adoptive MDSCs largely attenuated the inhibitory effect of NGA on the progression of pancreatic cancer. In addition, we showed that NGA significantly promoted apoptosis and inhibited the differentiation, migration and immunosuppressive function of MDSCs and decreased level of STAT3 and p-STAT3. Furthermore, we demonstrated that NGA synergistically enhanced the efficacy of anti-PD-1 antibodies against pancreatic cancer.

CONCLUSION

NGA inhibited the progression of pancreatic cancer by inhibiting MDSCs in the tumor microenvironment, and enhanced the efficacy of anti-PD-1 therapy in the treatment of pancreatic cancer.

BML-111 inhibits osteoclast differentiation by suppressing the MAPK and NF-κB pathways, alleviating deterioration of the knee joints in a CIA rat model

Irreversible destruction of joints is the hallmark of rheumatoid arthritis (RA). Osteoclasts are the only bone-resorbing cells and play an important role in joint rebuilding. BML-111 (5(S),6(R),7-trihydroxyheptanoic acid methyl ester, C₈ H₁₆ O₅ ) is a synthetic lipoxin A4 agonist with antioxidant and anti-inflammatory properties. The present study aimed to investigate the effect of BML-111 on osteoclasts in vivo and in vitro, to investigate its therapeutic effect on joint destruction in RA. Cell Counting Kit-8 assay and flow cytometry were used to exclude cytotoxic effects of BML-111 to bone marrow-derived macrophages (BMMs). Then, osteoclasts were differentiated in vitro from BMMs by used macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand, and osteoclasts were observed following tartrate-resistant acid phosphatase staining with or without BML-111 treatment. Meanwhile, absorption pit assay and immunofluorescence staining of the fibrous actin ring were used to observe osteoclast function. Moreover, we examined mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) activation. We established collagen-induced arthritis in a rat model and, after treatment with BML-111, joint swelling was measured and the knee joints were processed for histology. We also examined serum and tissue for osteoclastogenesis-related markers. BML-111 inhibited osteoclast formation and differentiation in a time- and concentration-dependent manner, and downregulated the expression levels of MAPK and NF-κB in vitro. Meanwhile, BML-111 effectively alleviated joint structural damage and inhibited osteoclast formation in vivo. BML-111 inhibited osteoclast formation and differentiation in vitro and in vivo, and delayed the progression of joint destruction.

Neogambogic acid relieves myocardial injury induced by sepsis via p38 MAPK/NF-κB pathway

Sepsis-associated myocardial injury, an invertible myocardial depression, is a common complication of sepsis. Neogambogic acid is an active compound in garcinia and exerts anthelmintic, anti-inflammatory, and detoxification properties. The role of neogambogic acid in sepsis-associated myocardial injury was assessed. Firstly, mice were pretreated with neogambogic acid and then subjected to lipopolysaccharide treatment to induce sepsis. Results showed that lipopolysaccharide treatment induced up-regulation of biomarkers involved in cardiac injury, including lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), and troponin I (cTnI). However, pretreatment with neogambogic acid reduced levels of LDH, CK-MB, and cTnI, and ameliorated histopathological changes in the heart tissues of septic mice. Secondly, neogambogic acid also improved cardiac function in septic mice through reduction in left ventricular end-diastolic pressure, and enhancement of ejection fraction, fractional shortening, and left ventricular systolic mean pressure. Moreover, neogambogic acid suppressed cardiac apoptosis and inflammation in septic mice and reduced cardiac fibrosis. Lastly, protein expression of p-p38, p-JNK, and p-NF-κB in septic mice was decreased by neogambogic acid. In conclusion, neogambogic acid exerted anti-apoptotic, anti-fibrotic, and anti-inflammatory effects in septic mice through the inactivation of MAPK/NF-κB pathway.

How zoledronic acid improves osteoporosis by acting on osteoclasts

Osteoporosis is called a silent disease, because it is difficult to detect until comprehensive examinations for osteoporosis are performed or osteoporotic fractures occur. Zoledronic acid is currently the first-line anti-osteoporotic drug, with good efficacy and treatment compliance. A major advantage of zoledronic acid is that intravenous zoledronic acid often guarantees a therapeutic effect for up to 1 year after infusion. The reasons why zoledronic acid is effective in improving osteoporosis are that it can inhibit osteoclast differentiation and induce osteoclast apoptosis, thus suppressing bone resorption and increasing bone density. The story between zoledronic acid and osteoclasts has been written long time ago. Both the canonical receptor activator of the receptor activator of nuclear factor-κB ligand (RANKL) pathway and the non-canonical Wnt pathway are the main pathways by which zoledronic acid inhibits osteoclast differentiation. Farnesyl pyrophosphate synthase (FPPS), reactive oxygen species (ROS), and ferroptosis that was first proposed in 2012, are all considered to be closely associated with zoledronic acid-induced osteoclast apoptosis. Here, we provide a brief review of the recent progress on the study of zoledronic acid and osteoclasts, and hope to elaborate how zoledronic acid improves osteoporosis by acting on osteoclasts.

A Review on the Molecular Mechanisms of Action of Natural Products in Preventing Bone Diseases

The drugs used for treating bone diseases (BDs), at present, elicit hazardous side effects that include certain types of cancers and strokes, hence the ongoing quest for the discovery of alternatives with little or no side effects. Natural products (NPs), mainly of plant origin, have shown compelling promise in the treatments of BDs, with little or no side effects. However, the paucity in knowledge of the mechanisms behind their activities on bone remodeling has remained a hindrance to NPs’ adoption. This review discusses the pathological development of some BDs, the NP-targeted components, and the actions exerted on bone remodeling signaling pathways (e.g., Receptor Activator of Nuclear Factor κ B-ligand (RANKL)/monocyte/macrophage colony-stimulating factor (M-CSF)/osteoprotegerin (OPG), mitogen-activated protein kinase (MAPK)s/c-Jun N-terminal kinase (JNK)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Kelch-like ECH-associated protein 1 (Keap-1)/nuclear factor erythroid 2–related factor 2 (Nrf2)/Heme Oxygenase-1 (HO-1), Bone Morphogenetic Protein 2 (BMP2)-Wnt/β-catenin, PhosphatidylInositol 3-Kinase (PI3K)/protein kinase B (Akt)/Glycogen Synthase Kinase 3 Beta (GSK3β), and other signaling pathways). Although majority of the studies on the osteoprotective properties of NPs against BDs were conducted ex vivo and mostly on animals, the use of NPs for treating human BDs and the prospects for future development remain promising.

Transcriptional Analysis of the Effects of Gambogic Acid and Neogambogic Acid on Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a major threat to human health, as this bacterium has developed resistance to a variety of conventional antibiotics. This is especially true of MRSA biofilms, which not only exhibit enhanced pathogenicity but also are resistant to most antibiotics. In this work, we demonstrated that two natural products with antitumor activity, namely, gambogic acid (GA) and neogambogic acid (NGA), have significant inhibitory activity toward MRSA. GA and NGA can not only effectively inhibit planktonic MRSA strains in vivo and in vitro, but also have strong inhibitory effects on MRSA biofilms formation. By transcriptome sequencing, Q-RT-PCR and PRM, we found that GA and NGA could reduce the expression of S. aureus virulence factors by inhibiting the saeRS two-component, thus achieving inhibition of MRSA. We found that GA and NGA had anti-MRSA activity in vivo and in vitro and identified saeRS to be the target, indicating that saeRS inhibitors may be used to treat biofilm-related infections.

The efficacy and potential mechanism of cnidium lactone to inhibit osteoclast differentiation

Cnidium lactone is effective in the maintenance of bone mass in various osteoporosis models; however, the precise molecular mechanisms are not understood. In this study, we investigated the effects and underlying mechanisms of action of cnidium lactone on receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis. Cnidium lactone dose-dependently inhibited osteoclast differentiation and formation, decreased the bone-resorbing activity of osteoclasts, and downregulated the expression of osteoclast differentiation marker genes. Cnidium lactone treatment considerably reduced RANKL-induced p38 MAPK and PI3K-Akt signal activity in RAW264.7 cells. The cnidium lactone-induced osteoclastogenesis was significantly attenuated by inhibition of p38 and PI3K through pretreatment with SB203580 and LY294002, respectively. Furthermore, cnidium lactone inhibited the expression of c-Fos and NFATc-1 with dose-dependently and enhanced by SB203580 and LY294002. In conclusion, cnidium lactone inhibits osteoclast differentiation through p38 MAPK and PI3K-Akt signalling pathway/c-Fos/NFATc1 signalling pathway.