Bicyclol mitigates lipopolysaccharide-induced acute lung injury through myeloid differentiation factor 88 inhibition.

Acute lung injury (ALI) remains a significant clinical challenge due to the absence of effective treatment alternatives. This study presents a new method that employs a screening platform focusing on MyD88 affinity, anti-inflammatory properties, and toxicity. This platform was used to evaluate a 300-compound library known for its anti-inflammatory potential. Among the screened compounds, Bicyclol emerged as a standout, exhibiting MyD88 binding and a significant reduction in LPS-stimulated pro-inflammatory factors production in mouse primary peritoneal macrophages. By targeting MyD88, Bicyclol disrupts the MyD88/TLR4 complex and MyD88 polymer formation, thereby mitigating the MAPKs and NF-κB signaling pathways. In vivo experiments further confirmed Bicyclol's efficacy, demonstrating alleviated ALI symptoms, decreased inflammatory cytokines level, and reduced inflammatory cells presence in lung tissues. These findings were associated with a decrease in mortality in LPS-challenged mice. Overall, Bicyclol represents a promising treatment option for ALI by specifically targeting MyD88 and limiting inflammatory responses.

Multifunctional self-healing peptide hydrogel for wound healing.

The complete healing of wounds remains a challenge in clinical care. In addition, various complications such as inflammation and infection that may occur during skin wound healing can impede the healing process. Here, we constructed a multifunctional self-repairing hydrogel by utilizing Schiff base bonds. This hydrogel exhibited good self-healing properties and could cope with destructive external influences. The self-healing hydrogel was injectable, ensuring that the hydrogel dressing adhered to the wound. Carboxymethyl chitosan and oxidized chondroitin sulfate demonstrated good biocompatibility and multiple bioactivities and were successfully used to prepare self-healing hydrogels. Meanwhile, the SIKVAV biopeptide was less expensive and more morphologically stable than vascular endothelial growth factor and had a high pro-angiogenic activity. Thus, the SIKVAV biopeptide was cross-linked to the oxidized chondroitin sulfate of the hydrogel through covalent bonding to avoid rapid biopeptide degradation, achieving a slow release of the drug. This peptide hydrogel exhibited good biocompatibility and antimicrobial properties; moreover, experiments conducted on mice revealed that it could effectively promote angiogenesis and skin tissue repair. These findings suggest that the injectable self-repairing peptide hydrogel may facilitate skin wound healing and other applications.

Cytotoxic secondary metabolites isolated from Penicillium sp. YT2019-3321, an endophytic fungus derived from Lonicera Japonica.

Introduction: Endophytic fungi associated with medicinal plants have proven to possess a high potential to produce structurally diverse metabolites, some of which are valuable for medicinal applications. In this study, Penicillium sp. YT2019-3321, an endophytic fungus derived from traditional Chinese medicine Lonicera japonica, was chemically studied. Methods: The chemical structures of the isolated compounds were established by a correlative interpretation of HRESIMS and NMR spectroscopic data. The optical resolution of (±)-1 by chiral HPLC yielded individual enantiomers (+)-1 and (-)-1, and their stereochemistry were solved by X-ray diffraction crystallography, respectively. Results and discussion: Eight structurally diversified secondary metabolites, including two previously unreported polyketides, named (±)-chrysoalide B (1) and penicidone E (2), were isolated and identified from Penicillium sp. YT2019-3321. Compound 2 possessed the γ-pyridone nucleus, which is rarely found in natural products. Cytotoxic assay revealed that the new compound 2 demonstrated a dose-dependent cytotoxicity against the human pancreatic tumor cells PATU8988T with the IC50 value of 11.4 µM. Further studies indicated that 2 significantly induced apoptosis of PATU8988T cell lines, characterized by the morphologies abnormity, the reduction of cell number, the upregulation of proportion of apoptotic cells, and the ratio of Bcl-2 to Bax. Our study demonstrates that fungal secondary metabolites may have important significance in the discovery of drug leads.

Polyketides isolated from an endophyte Penicillium oxalicum 2021CDF-3 inhibit pancreatic tumor growth.

Fungal secondary metabolites are inherently considered valuable resources for new drugs discovery. To search for novel fungal secondary metabolites with lead compounds potential, a fungal strain Penicillium oxalicum 2021CDF-3, an endophyte of the marine red algae Rhodomela confervoides, was chemically studied. Cultivation of this fungus on solid rice medium yielded 10 structurally diverse metabolites (1-10), including two new polyketides, namely oxalichroman A (1) and oxalihexane A (2). Their structures were determined by detailed analysis of NMR and HRESIMS spectroscopic data. Oxalihexane A (2) was elucidated as a novel polyketide formed by a cyclohexane and cyclohexanone moiety via an ether bond. The stereochemistry of 2 was successfully assigned by NMR and ECD calculations. In the cytotoxic assay, the new compound 2 showed remarkable inhibitory effect on the human pancreatic cancer PATU8988T cell line. Further pharmacological study demonstrated that the expression level of Cyclin D1 was down-regulated by the treatment with 2, which suggested that cell cyclin abnormity was involved in pancreatic tumor cell apoptosis. Moreover, the activation of Wnt5a/Cyclin D1 signaling pathway might be involved in the mechanism of panreatic tumor cell apoptosis induced by 2.

How do farmland rental markets affect farmers' income? Evidence from a matched renting-in and renting-out household survey in Northeast China.

Promoting farmland transfer through the farmland rental market is an essential instrument to achieve the scale economy of agricultural production in China. However, past literature on the land reform in China pays more attention to the renting-in household or the renting-out household, respectively, less to both types of households together. Using a large-scale survey of farm households in China, we examine the determinants of participation in the farmland rental market and quantify the impact of the rental market on farmers' income. Findings show household off-farm income, family members' part-time employment, agricultural subsidies, and participation in agricultural cooperatives significantly affect farmers' participation in the farmland rental market. Participation in the farmland rental market significantly increases the income of renting-in households, while it decreases the income of renting-out households, which might result from the temporary lag effect of the land system reform.

Compound LM9, a novel MyD88 inhibitor, efficiently mitigates inflammatory responses and fibrosis in obesity-induced cardiomyopathy.

Mechanisms of cardiomyopathy caused by obesity/hyperlipidemia are complicated. Obesity is usually associated with chronic low-grade inflammation and may lead to the onset and progression of myocardial fibrosis and remodeling. TLR4/MyD88 signaling pathway, as a key regulator of inflammation, plays an important role in the pathogenesis of obesity-induced cardiomyopathy. We previously demonstrated that LM9, a novel MyD88 inhibitor, attenuated inflammatory responses and fibrosis in obesity-induced cardiomyopathy by inhibiting the formation of TLR4/MyD88 complex. In this study, we investigated the protective effects of LM9 on obesity-induced cardiomyopathy in vitro and in vivo. We showed that LM9 (5, 10 µM) significantly attenuates palmitic acid (PA)-induced inflammation in mouse peritoneal macrophages, evidenced by decreased expression of proinflammatory genes including TNF-α, IL-6, IL-1ß, and ICAM-1. In cardiac-derived H9C2 cells, LM9 treatment suppressed PA-induced inflammation, lipid accumulation, and fibrotic responses. In addition, LM9 treatment also inhibited PA-activated TLR4/MyD88/NF-κB signaling pathway. We further revealed in HEK293 cells that LM9 treatment blocked the TLR4/MyD88 binding and MyD88 homodimer formation. In HFD-fed mice, administration of LM9 (5, 10 mg/kg, ig, every other days for 8 weeks) dose-dependently alleviated inflammation and fibrosis in heart tissues and decreased serum lipid concentration. In conclusion, this study demonstrates that MyD88 inhibitor LM9 exerts protective effects against obesity-induced cardiomyopathy, suggesting LM9 to be a promising therapeutic candidate drug for the obesity-related cardiac complications.

Inhibition of myeloid differentiation factor 2 by baicalein protects against acute lung injury.

BACKGROUND: ALI/ARDS is characterized by severe hypoxemic respiratory failure attributed to inflammatory tissue injury. There are no treatment modalities able to prevent/reverse the dire pathological sequelae in these patients. Evidence links the inflammatory lung injury to uncontrolled activation of the immune signaling complex, TLR4-MD2 (Toll-like receptor-myeloid differentiation factor 2). Baicalein, a natural flavonoid, is reported to have robust anti-inflammatory properties, but its inhibition mechanism remains unclear. HYPOTHESIS/PURPOSE: This study investigated the protective mechanisms of baicalein on ALI/ARDS. METHODS: We used two experimental mouse models of LPS-induced ALI, pulmonary infection model (intratracheal LPS), and systemic infection model (intravenous LPS). Blood, BALF, lung and liver tissues were analyzed using routine methods. In vitro studies using peritoneal mouse macrophages or recombinant proteins were designed to elucidate inhibition mechanisms of baicalein. RESULTS: Our critical new findings revealed that Baicalein was an MD2 inhibitor, directly bound to MD2, effectively suppressing TLR4-MD2 activation and the subsequent MAPK and NF-κB signaling. The inhibited MD2 prevented development of inflammatory tissue injury and improved survival. The importance of MD2 in the inflammatory injury in ALI was corroborated by data obtained from MD2-/- mice, which did not develop the characteristic LPS-induced lung tissue damage. Thus, the findings indicated that MD2 was critical for development of ALI, functioning as an early upstream signal driving the progression of inflammatory injury. CONCLUSION: Baicalein, as a direct and selective MD2 inhibitor, inhibited the early upstream TLR4-MD2 signaling and is a promising therapeutic agent for the treatment of ALI/ARDS.

A novel resveratrol analog PA19 attenuates obesity­induced cardiac and renal injury by inhibiting inflammation and inflammatory cell infiltration.

Obesity is a major global health concern and induces numerous complications, such as heart and kidney injury. Inflammation is an important pathogenic mechanism underlying obesity­associated tissue injury. (1E,4E)­1­{2,4­Dimethoxy­6­[(E)­4­methoxystyryl]phenyl}­5­â€‹(2,4­dimethoxyphenyl)penta­1,4­dien­3­one (PA19) is a novel anti­inflammatory compound synthesized by our research group. In the present study, the efficacy of PA19 in attenuating high­fat diet (HFD)­induced heart and kidney injury was investigated. Heart and kidney pathological injury and fibrosis were detected by hematoxylin and eosin and Sirius red staining, respectively. The expression levels of inflammatory genes and fibrosis­associated protein were determined by reverse transcription­quantitative polymerase chain reaction and western blotting. ELISA was used to detect the level of inflammatory cytokines. Following 20 weeks of HFD treatment, mice exhibited increased lipid accumulation in the serum, heart and kidney injury and fibrosis, and inflammation and inflammatory cell infiltration compared with mice fed a control diet. Conversely, treatment with PA19 during the final 12 weeks of the study significantly reduced the degree of heart and kidney fibrosis and inflammation induced by HFD. The results suggested that PA19 attenuates heart and kidney inflammation and injury induced by HFD, and indicated that PA19 may be a novel therapeutic agent in the treatment of obesity, and obesity­induced cardiac and renal injury.

Kaempferol reduces K63-linked polyubiquitination to inhibit nuclear factor-κB and inflammatory responses in acute lung injury in mice.

Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), pose a major clinical challenge. The major driving force in this syndrome is pulmonary inflammation. Recent studies have shown that the naturally occurring flavonoid kaempferol (KPF) reduces endotoxin-induced inflammatory responses in mice. However, the mechanisms of these anti-inflammatory activities are not currently known. Here, we show that enhanced inflammatory cytokine production in response to lipopolysaccharide (LPS) is due to increased TGF-ß-activated kinase-1 (TAK1) phosphorylation with subsequent activation of nuclear factor-κB (NF-κB). KPF attenuates LPS-mediated production of cytokines as well as activation of NF-κB. Furthermore, we identified that KPF prevents increased K63-linked polyubiquitination on TNF receptor associated factor-6 (TRAF6) and interleukin-1 receptor-associated kinase 1 (IRAK1). K63-linked polyubiquitination is a signal leading to enhanced activation of downstream pathways including TAK1. Our study shows that KPF is effective in reducing lung damage induced by LPS by modulating TRAF6 polyubiquitination. Furthermore, our findings may provide novel molecular targets to alleviate acute lung injury.

Development of 2-amino-4-phenylthiazole analogues to disrupt myeloid differentiation factor 88 and prevent inflammatory responses in acute lung injury.

Myeloid differentiation primary response protein 88 (MyD88), an essential adapter protein used by toll-like receptors (TLR), is a promising target molecule for the treatment of respiratory inflammatory diseases. Previous studies explored the activities of novel 2-amino-4-phenylthiazole analogue (6) in inflammation-induced cancer, and identified the analogue as an inhibitor of MyD88 toll/interleukin-1 receptor (TIR) homology domain dimerization. Here, we describe the synthesis of 47 new analogues by modifying different sites on this lead compound and assessed their anti-inflammatory activities in lipopolysaccharide-induced mouse primary peritoneal macrophages (MPMs). The most promising compound, 15d, was found to effectively interact with MyD88 protein and prevented formation of the MyD88 homodimeric complex. Furthermore, 15d showed in vivo anti-inflammatory activity in LPS-caused model of acute lung injury. This work provides new candidates as MyD88 inhibitors to combat inflammation diseases.

Design, synthesis and biological evaluation of novel 2-sulfonylindoles as potential anti-inflammatory therapeutic agents for treatment of acute lung injury.

Acute lung injury (ALI) is primarily driven by inflammation that severely impacts lung function. Novel 2-sulfonylindoles were recently shown to exhibit anti-inflammatory activity through the inhibition of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) production. Here, we synthesized 31 compounds which contained 2-sulfonylindole structure. The compounds 8a, 9g, 9h and 9k exhibited dose-dependent anti-inflammatory activity in vitro. Structural-activity relationship analysis revealed that the introduction of sulfonyl group in indole nucleus may be successful to obtain new anti-inflammatory structures and leads. The compounds 9h and 9k also decreased liposaccharide (LPS)-induced IL-6, IL-1ß and vascular cell adhesion molecule-1 (VCAM-1) mRNA expression, both in vitro and in an in vivo model of ALI. Furthermore, the compounds 9h and 9k at a high dose (20 mg/kg) significantly protected against LPS-induced ALI in mice. These results show that compounds 9h and 9k could be a promising lead structure for the treatment of ALI.

An Aza resveratrol-chalcone derivative 6b protects mice against diabetic cardiomyopathy by alleviating inflammation and oxidative stress.

Inflammation and oxidative stress play a crucial role in the development of diabetic cardiomyopathy (DCM). We previously had synthesized an Aza resveratrol-chalcone derivative 6b, of which effectively suppressing lipopolysaccharide (LPS)-induced inflammatory response in macrophages. This study aimed to investigate the potential protective effect of 6b on DCM and underlying mechanism. In H9c2 myocardial cells, 6b potently decreased high glucose (HG)-induced cell fibrosis, hypertrophy and apoptosis, alleviating inflammatory response and oxidant stress. In STZ-induced type 1 diabetic mice (STZ-DM1), orally administration with 6b for 16 weeks significantly attenuated cardiac hypertrophy, apoptosis and fibrosis. The expression of inflammatory cytokines and oxidative stress biomarkers was also suppressed by 6b distinctly, without affecting blood glucose and body weight. The anti-inflammatory and antioxidative activities of 6b were mechanistic associated with nuclear factor-kappa B (NF-κB) nucleus entry blockage and Nrf2 activation both in vitro and in vivo. The results indicated that 6b can be a promising cardioprotective agent in treatment of DCM via inhibiting inflammation and alleviating oxidative stress. This study also validated the important role of NF-κB and Nrf2 taken in the pathogenesis of DCM, which could be therapeutic targets for diabetic comorbidities.

Discovery of caffeic acid phenethyl ester derivatives as novel myeloid differentiation protein 2 inhibitors for treatment of acute lung injury.

Myeloid differentiation protein 2 (MD2) is an essential molecule which recognizes lipopolysaccharide (LPS), leading to initiation of inflammation through the activation of Toll-like receptor 4 (TLR4) signaling. Caffeic acid phenethyl ester (CAPE) from propolis of honeybee hives could interfere interactions between LPS and the TLR4/MD2 complex, and thereby has promising anti-inflammatory properties. In this study, we designed and synthesized 48 CAPE derivatives and evaluated their anti-inflammatory activities in mouse primary peritoneal macrophages (MPMs) activated by LPS. The most active compound, 10s, was found to bind with MD2 with high affinity, which prevented formation of the LPS/MD2/TLR4 complex. The binding mode of 10s revealed that the major interactions with MD2 were established via two key hydrogen bonds and hydrophobic interactions. Furthermore, 10s showed remarkable protective effects against LPS-caused ALI (acute lung injury) in vivo. Taken together, this work provides new lead structures and candidates as MD2 inhibitors for the development of anti-inflammatory drugs.

Shikonin inhibits myeloid differentiation protein 2 to prevent LPS-induced acute lung injury.

BACKGROUND AND PURPOSE: Acute lung injury (ALI) is a challenging clinical syndrome, which manifests as an acute inflammatory response. Myeloid differentiation protein 2 (MD2) has an important role in mediating LPS-induced inflammation. Currently, there are no effective molecular-based therapies for ALI or viable biomarkers for predicting the severity of disease. Recent preclinical studies have shown that shikonin, a natural naphthoquinone, prevents LPS-induced inflammation. However, little is known about the underlying mechanisms. EXPERIMENTAL APPROACH: The binding affinity of shikonin to MD2 was analysed using computer docking, surface plasmon resonance analysis and elisa. In vitro, the anti-inflammatory effect and mechanism of shikonin were investigated through elisa, real-time quantitative reverse transcription PCR, Western blotting and immunoprecipitation assay. In vivo, lung injury was induced by intratracheal administration of LPS and assessed by changes in the histopathological and inflammatory markers. The underlying mechanisms were investigated by immunoprecipitation in lung tissue. KEY RESULTS: Shikonin directly bound to MD2 and interfered with the activation of toll-like receptor 4 (TLR4) induced by LPS. In cultured macrophages, shikonin inhibited TLR4 signalling and pro-inflammatory cytokine production. These effects were produced through suppression of key signalling proteins including the NF-κB and the MAPK pathway. We also showed that shikonin inhibits MD2-TLR4 complex formation and reduces LPS-induced inflammatory responses in a mouse model of ALI. CONCLUSIONS AND IMPLICATIONS: Our studies have uncovered the mechanism underlying the biological activity of shikonin in ALI and suggest that the targeting of MD2 may prove to be beneficial as a treatment option for this condition.