Therapeutic effects of 5,2'-dibromo-2,4',5'-trihydroxydiphenylmethanone (LM49) in an experimental rat model of acute pyelonephritis by immunomodulation and anti-inflammation

SIRT1-dependent mitochondrial biogenesis supports therapeutic effects of 4-butyl-polyhydroxybenzophenone compounds against NAFLD

The mitochondria have been identified as key targets in nonalcoholic fatty liver disease (NAFLD), one of the most prevalent chronic liver damage diseases globally. Meanwhile, the biological information analysis in this study revealed that SIRT1, PPARG, PPARA, and PPARGC1A (mitochondrial biogenesis-related proteins) were NAFLD therapeutic targets. Therefore, the design and synthesis of targeted drugs that promote mitochondrial biogenesis and improve mitochondrial function are particularly important for NAFLD treatment. Recently, we introduced butyls, hydroxyls, and halogens to benzophenone and synthesized a series of NAFLD-related 4-butylpolyhydroxybenzophenone compounds, aiming at investigating the hepatoprotective activity from the aspect of mitochondrial biogenesis. The structure-activity relationship demonstrated that hydroxyl and ketone groups were active groups interacting with mitochondrial biogenesis proteins (SIRT1 and PGC1α), and the activity was stronger when the o-hydroxyl group was present on the benzene ring. In contrast, the activity was little affected by the presence of the p-hydroxyl group, m-hydroxyl group, butyl group type, or halogen. In addition, in vitro studies confirmed that these compounds could directly bind to SIRT1 and PGC1α, markedly promote their interaction, significantly increase the expression of proteins and genes related to mitochondrial biogenesis (SIRT1, PGC1α, NRF1, TFAM, COX1, and ND6) and subsequently ameliorate mitochondria dysfunction, which was evidenced by the decreased ROS, upregulated ATP production, increased MMP, and enhanced mitochondrial number. According to the outcomes of our in vitro and in vivo experiments, 4-butyl-polyhydroxybenzophenone compounds could also effectively reduce the formation of lipid droplets and liver injury index (ALT, AST, LDH, AKP, γ-GT, and GDH) and improve the level of antioxidant enzymes (GSH and SOD). Particularly, the treatment of these compounds after a high-fat diet could significantly reduce body weight, decrease liver coefficient, attenuate liver damage, and ameliorate lipid accumulation in rat liver, demonstrating their therapeutic effects on NAFLD. Mechanistically, 4-butyl-polyhydroxybenzophenone compounds promoted mitochondrial biogenesis and eventually prevented NAFLD liver injury by activating the PGC1α signaling pathway in a SIRT1-dependent manner, which was strongly supported by SIRT1 inhibitor EX527.

GSK3β-dependent lysosome biogenesis: An effective pathway to mitigate renal fibrosis with LM49

Renal fibrosis is an incurable disorder characterised by an imbalance of the extracellular matrix (ECM) favouring excess production over degradation. The identification of actionable pathways and agents that promote ECM degradation to restore ECM homeostasis may help mitigate renal fibrosis. In this study, we identified 5,2′-dibromo-2,4′,5′-trihydroxydiphenylmethanone (LM49), a compound we previously synthesised, as a small-molecule inducer of ECM degradation. LM49 administration efficiently reduced ECM deposition in renal tissue of diabetic nephropathy rats and in transforming growth factor β-treated renal fibroblast cells. LM49 promoted the cytosol-to-nucleus translocation of transcription factor EB (TFEB) to increase lysosome biogenesis, leading to lysosome-based degradation of the ECM. TFEB-mediated lysosome biogenesis was induced by LM49 directly inhibiting the activity of glycogen synthase kinase 3β (GSK3β) rather than mammalian target of rapamycin complex 1. LM49 inhibited GSK3β kinase activity concentration-dependently via competing with ATP. Direct binding between LM49 and GSK3β was confirmed by the bio-layer interferometry assay, cellular thermal shift assay, and drug affinity responsive target stability. A molecular docking and molecular dynamic simulation revealed that LM49 occupied the ATP pocket of GSK3β, which was consistent with the kinase activity assay. In summary, LM49 enhances TFEB-mediated lysosome biogenesis by directly inhibiting GSK3β, leading to the degradation of the ECM by lysosomes. The enhancement of GSK3β-dependent lysosome biogenesis to rebalance the ECM may be a novel strategy to counteract renal fibrosis, and LM49 may be a viable clinical candidate for treating this disorder.

Adiponectin alleviated renal cell apoptosis and inflammation via inactivation of JAK2/STAT3 signal pathway in an acute pyelonephritis mouse model

Background

Acute pyelonephritis (APN), an acute and severe kidney infection, is usually treated with antibiotics. However, APN treatment has become increasingly challenging because of bacterial resistance. Adiponectin, an adipokine, has recently been reported to exhibit profound anti-inflammatory and anti-apoptotic effects. However, the effect of adiponectin on the outcomes of APN treatment remains unclear. In this study, we aimed to investigate the effects of adiponectin on APN and the mechanisms underlying these effects.

Methods

Wild-type C57 mice and adiponectin-knockout (KO) mice were divided into 6 groups: the wild-type control group, the wild-type model group, the wild-type adiponectin intervention group, the KO control group, the KO model group, and the adiponectin-KO intervention group. We measured white blood cell (WBC) and neutrophil counts (NC) using a multispecies hematology analyzer; tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) using enzyme-linked immunosorbent assay (ELISA); blood urea nitrogen (BUN) and serum creatinine (SCr) levels using colorimetry; and the protein levels of JAK2, STAT3, p-JAK2, p-STAT3, Bcl-2, and Bax in renal tissues using western blot analysis. Apoptotic cells were detected using the transferase-mediated dUTP nick end labelling (TUNEL) assay.

Results

Compared to the wild-type mice, the KO mice showed a more severe inflammatory response and kidney damage after Escherichia coli infection. After treatment with exogenous adiponectin injection, the inflammatory response, oxidative stress, and kidney damage were partly alleviated. Adiponectin KO led to JAK2/STAT3 signaling activation, and exogenous adiponectin administration inactivated JAK2/STAT3 signaling in the APN model. APN can lead to an increase in the level of the protein Bax and a decrease in the level of the bcl-2 protein, thereby increasing apoptosis; this effect was inhibited by adiponectin.

Conclusions

Through use of a pyelonephritis mouse model, we demonstrated that adiponectin might alleviate renal cell apoptosis and inflammatory response by inactivating the JAK2/STAT3 signaling pathway.

An active marine halophenol derivative attenuates lipopolysaccharide-induced acute liver injury in mice by improving M2 macrophage-mediated therapy

2,4',5'-Trihydroxyl-5,2'-dibromo diphenylmethanone (LM49), an active halophenol derivative synthesized by our group, which exhibits a broad spectrum of therapeutic properties, such as antioxidant and anti-inflammatory activities. In this study, we found LM49 could obviously attenuate acute liver injury induced by lipopolysaccharide (LPS) in mice by polarizing macrophages. The protective effect was described by reducing the hepatic inflammation and improving hepatic function using aspartate transaminase (AST) and alanine transaminase (ALT) assay. Further study revealed that LM49 pretreatment induced the Kupffer cells (KCs) to M2 polarization and decreased the production of inflammatory cytokines. The action mechanism in RAW 264.7 macrophages showed that LM49 could induce the activation of JAK1/STAT6 signaling pathway and the inhibition of TLR-4/NF-kB axis. Morever, LM49 also upregulated the expression of SOCS1 and FLK-4, which can promote M2 polarization by cooperating with STAT6 and inhibit M1 formation by reducing JAK1/STAT1. Our results suggested that LM49 could protect against LPS-induced acute liver injury in mice via anti-inflammatory signaling pathways and subsequent induction of M2 Kupffer cells. The results provided the first experimental evidence of active halophenols for the anti-inflammatory therapy by targeting M2 macrophages.

Progress of Bromophenols in Marine Algae from 2011 to 2020: Structure, Bioactivities, and Applications

Marine algae contain various bromophenols that have been shown to possess a variety of biological activities, including antiradical, antimicrobial, anticancer, antidiabetic, anti-inflammatory effects, and so on. Here, we briefly review the recent progress of these marine algae biomaterials and their derivatives from 2011 to 2020, with respect to structure, bioactivities, and their potential application as pharmaceuticals.

A novel marine halophenol derivative attenuates lipopolysaccharide-induced inflammation in RAW264.7 cells via activating phosphoinositide 3-kinase/Akt pathway

BACKGROUND

2,4',5'-Trihydroxyl-5,2'-dibromo diphenylmethanone (LM49), a novel active halophenol derivative synthesized by our group from marine plants, exhibits strong anti-inflammatory activities. However, molecular machineries involved in its effect have not been fully identified. The study was aimed to investigate the anti-inflammatory effect of LM49 on lipopolysaccharide (LPS)-stimulated RAW264.7 cells and its underlying mechanism.

METHODS

RAW264.7 cells were treated with LPS (10 μg/mL) and then exposed to different concentrations of LM49 (i.e., 5, 10, and 15 μM) for 24 h. Cytokine release in culture medium of RAW264.7 cells was measured by enzyme-linked immunosorbent assay (ELISA). Phagocytic capacity (FITC-dextran uptake) was determined by flow cytometry. The protein level of phosphoinositide 3-kinase (PI3K), AKT and p-AKT was measured by western blot analysis.

RESULTS

Our findings revealed that LM49 reduced the production and mRNA levels of cytokines related to inflammation such as interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α), and increased the level of IL-10, an anti-inflammatory cytokine. In addition, LM49 decreased the production of nitric oxide and reactive oxygen species. Moreover, flow cytometry showed that LM49 significantly enhanced the phagocytic capacity (FITC-dextran uptake) of macrophages. The effects of LM49 were significantly inhibited by the phosphoinositide 3-kinase (PI3K) inhibitor, LY294002. In particular, LY294002 attenuated the phagocytic capacity of RAW264.7 cells induced by LM49 and prevented the effects on cytokines.

CONCLUSION

These findings suggest that LM49 possesses anti-inflammatory activity on LPS-stimulated RAW264.7 cells, in which the PI3K/Akt pathway plays an essential role. LM49 may have clinical utility as an anti-inflammatory agent. In this study, we demonstrated that a halophenol derivative (LM49) could possess anti-inflammatory activity on LPS-stimulated RAW264.7 cells by reducing pro-inflammatory cytokines and enhancing the phagocytic capacity, in which the PI3K/Akt pathway plays an essential role. LM49 may have clinical utility as an anti-inflammatory agent.

Process Development and Synthesis of Process-Related Impurities of an Efficient Scale-Up Preparation of 5,2'-Dibromo-2,4',5'-Trihydroxy Diphenylmethanone as a New Acute Pyelonephritis Candidate Drug

Based on a foregoing gram-scale laboratory process, an efficient scale-up preparation process of 5,2'-dibromo-2,4',5'-trihydroxydiphenylmethanone (LM49-API), a new acute pyelonephritis candidate drug, was developed and validated aiming to reduce by-products and achieve better impurity profiles. Meanwhile, the polymorph of LM49-API and process-related impurities were also investigated. Ultimately, the optimal reaction conditions were verified by evaluating the impurity profiles and their formation during the synthesis. Six process-related impurities were synthesized and identified, being useful for the quality control of LM49-API. Its finalized preparation process was further validated at 329-410 g scale-up production in 53.4-57.1% overall yield with 99.95-99.98% high-performance liquid chromatography (HPLC) purity, and it is currently viable for commercial production. LM49-API-imC and LM49-API-imX were identified as the main single impurities in LM49-API, with the content controlled to be less than 0.03%.