Esculentoside A protects against osteoarthritis by ameliorating inflammation and repressing osteoclastogenesis

Protective effect of esculentoside A against myocardial infarction via targeting C-X-C motif chemokine receptor 2

Myocardial infarction (MI) is the primary cause of cardiac mortality. Esculentoside A (EsA), a triterpenoid saponin, has anti-inflammatory and antioxidant activities. However, its effect on MI remains unknown. In this study, the protective effect and mechanisms of EsA against MI were investigated. EsA significantly alleviated hypoxia-induced HL-1 cell injury, including increasing cell viability, inhibiting reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP) and lactate dehydrogenase (LDH) leakage. In mouse MI model by left coronary artery (LAD) ligating, EsA obviously restored serum levels of creatine kinase isoenzymes (CK-MB), cardiac troponin I (cTnI), superoxide dismutase (SOD) and malondialdehyde (MDA). In addition, the cardioprotective effect of EsA was further confirmed by infarct size, electrocardiogram and echocardiography. Mechanistically, the targeted binding relationship between EsA and C-X-C motif chemokine receptor 2 (CXCR2) was predicted by molecular docking and dynamics, and validated by small molecule pull-down and surface plasmon resonance tests. EsA inhibited CXCR2 level both in vitro and in vivo, correspondingly alleviated oxidative stress by suppressing NOX1 and NOX2 and relieved inflammation through inhibiting p65 and p-p65. It demonstrated that EsA could play a cardioprotective role by targeting CXCR2. However, the effect of EsA against MI was abolished in combination with CXCR2 overexpression both in vitro and in vivo. This study revealed that EsA showed excellent cardioprotective activities by targeting CXCR2 to alleviate oxidative stress and inflammation in MI. EsA may function as a novel CXCR2 inhibitor and a potent candidate for the prevention and intervention of MI in the future.

Esculentoside A ameliorates DNCB-induced atopic dermatitis by suppressing the ROS-NLRP3 axis via activating the Nrf2 pathway

Atopic dermatitis (AD) is a chronic inflammatory skin condition with a high prevalence. Inflammation and oxidative stress are strongly associated with AD progression. Esculentoside A (EsA) inhibits inflammation and oxidative stress in various diseases. However, whether EsA mitigates AD by suppressing inflammation and oxidative stress remains unknown. A mouse model of AD was constructed by the induction of 1-chloro-2,4-dinitrochlorobenzene (DNCB). The mechanism of EsA and its effects on AD symptoms, pathology, inflammation and oxidative stress were investigated through histopathological staining, enzyme-linked immunosorbent assay, blood cells analysis, colorimetric measurement and western blot analysis. EsA improved the clinical symptoms and increased clinical skin scores in AD mice. Skin thickening of the epidermis and dermal tissues and the mast cell numbers in AD mice were reduced with the EsA treatment. EsA decreased the relative mRNA level of thymic stromal lymphopoietin, interleukin (IL)-4, IL-5 and IL-13; the serum concentrations of immunoglobulin E (IgE) and IL-6; and the numbers of white blood cells (WBC) and WBC subtypes, including basophil, lymphocytes, eosinophil, neutrophil and monocytes in DNCB-induced mice. DNCB caused higher levels of oxidative stress, which was reversed with the administration of EsA. Mechanically, EsA upregulated the expression of Nrf2 but downregulated the level of NLRP3 inflammasome in AD mice. The inhibitor of Nrf2 significantly recovered the EsA-induced changes in the NLRP3 inflammasome proteins in DNCB-treated mice. Therefore, EsA improved the clinical and pathological symptoms, inflammation and oxidative stress experienced by DNCB-induced mice and was involved in the inactivation of NLRP3 inflammasome by activating Nrf2.

Therapeutics of osteoarthritis and pharmacological mechanisms: A focus on RANK/RANKL signaling

Osteoarthritis (OA) is a chronic degenerative disease afflicting millions globally. Despite the development of numerous pharmacological treatments for OA, a substantial unmet need for effective therapies persists. The RANK/RANKL signaling pathway has emerged as a promising therapeutic target for OA, owing to its pivotal role in regulating osteoclast differentiation and activity. In this comprehensive review, we aim to elucidate the relevant mechanisms of OA mediated by RANK/RANKL signaling, including bone remodeling, inflammation, cartilage degradation, osteophyte formation, and pain sensitization. Furthermore, we discuss and summarize the cutting-edge strategies targeting RANK/RANKL signaling for OA therapy, encompassing approaches such as gene-based interventions and biomaterials-aided pharmacotherapy. In addition, we highlight the prevailing challenges associated with pharmacological OA treatments and explore potential future directions, approached through a clinical-translational lens.

Esculentoside A ameliorates BSCB destruction in SCI rat by attenuating the TLR4 pathway in vascular endothelial cells

BACKGROUND AND AIMS

Overexpressed MMP-9 in vascular endothelial cells is involved in blood spinal cord barrier (BSCB) dysfunction in spinal cord injury (SCI). Esculentoside A (EsA) has anti-inflammatory and cell protective effects. This study aimed to evaluate its effects on neuromotor function in SCI rats, as well as the potential mechanisms.

METHODS

The therapeutic effect of EsA in SCI rats was investigated using Basso-Beattie-Bresnahan (BBB) scores, a grid walk test and histological analyses. To assess the protective role of EsA in the BSCB and in oxygen glucose deprivation/reoxygenation (OGD/R)-induced hBMECs, the BSCB function, tight junctions (TJ) protein (ZO-1 and claudin-5) expression, structure of the BSCB and Matrix metalloproteinase-9 (MMP-9) expression were observed via Evans blue (EB) detection, immunofluorescence analyses and western blotting. Molecular docking simulations and additional experiments were performed to explore the potential mechanisms by which EsA maintains the function of the BSCB in vivo and in vitro.

RESULTS

EsA treatment improved BBB scores, reduced cavity formation and the loss of neuronal cells, demonstrating an improvement in motor function in SCI rats. In vivo experiments showed that EsA decreased the infiltration of blood cells and inflammatory mediators (IL-1β, IL-6 and TNF-α) and protected the structure of TJs in the rat spinal cord and in OGD/R-induced hBMECs. EsA inhibited the activation of Toll-like receptor 4 (TLR4) signalling, which may be related to the protective effect of EsA against MMP-9-induced BSCB damage.

CONCLUSIONS

EsA downregulated MMP-9 expression in vascular endothelial cells, protected BSCB function in SCI rats and attenuated TLR4 signalling and thus provide new options for the treatment of SCI.

Vindoline Attenuates Osteoarthritis Progression Through Suppressing the NF-κB and ERK Pathways in Both Chondrocytes and Subchondral Osteoclasts

Disruption of extracellular matrix (ECM) homeostasis and subchondral bone remodeling play significant roles in osteoarthritis (OA) pathogenesis. Vindoline (Vin), an indole alkaloid extracted from the medicinal plant Catharanthus roseus, possesses anti-inflammatory properties. According to previous studies, inflammation is closely associated with osteoclast differentiation and the disorders of the homeostasis between ECM. Although Vin has demonstrated effective anti-inflammatory properties, its effects on the progression of OA remain unclear. We hypothesized that Vin may suppress the progress of OA by suppressing osteoclastogenesis and stabilizing ECM of articular cartilage. Therefore, we investigated the effects and molecular mechanisms of Vin as a treatment for OA in vitro and in vivo. In the present study, we found that Vin significantly suppressed RANKL-induced osteoclast formation and obviously stabilized the disorders of the ECM homeostasis stimulated by IL-1β in a dose-dependent manner. The mRNA expressions of osteoclast-specific genes were inhibited by Vin treatment. Vin also suppressed IL-1β-induced mRNA expressions of catabolism and protected the mRNA expressions of anabolism. Moreover, Vin notably inhibited the activation of RANKL-induced and IL-1β-induced NF-κB and ERK pathways. In vivo, Vin played a protective role by inhibiting osteoclast formation and stabilizing cartilage ECM in destabilization of the medial meniscus (DMM)-induced OA mice. Collectively, our observations provide a molecular-level basis for Vin’s potential in the treatment of OA.

Cartilage-targeting peptide-modified dual-drug delivery nanoplatform with NIR laser response for osteoarthritis therapy

Cartilage-targeting delivery of therapeutic agents is still an effective strategy for osteoarthritis (OA) therapy. Recently, scavenging for reactive oxygen species (ROS) and activating autophagy have been increasingly reported to treat OA effectively. In this study, we designed, for the first time, a dual-drug delivery system based on metal organic framework (MOF)-decorated mesoporous polydopamine (MPDA) which composed of rapamycin (Rap) loaded into the mesopores and bilirubin (Br) loaded onto the shell of MOF. The collagen II-targeting peptide (WYRGRL) was then conjugated on the surface of above nanocarrier to develop a cartilage-targeting dual-drug delivery nanoplatform (RB@MPMW). Our results indicated the sequential release of two agents from RB@MPMW could be achieved via near-infrared (NIR) laser irritation. Briefly, the rapid release of Br from the MOF shell exhibited excellent ROS scavenging ability and anti-apoptosis effects, however responsively reduced autophagy activity, to a certain extent. Meanwhile, following the NIR irradiation, Rap was rapidly released from MPDA core and further enhanced autophagy activation and chondrocyte protection. RB@MPMW continuously phosphorylated AMPK and further rescued mitochondrial energy metabolism of chondrocytes following IL-1β stimulation via activating SIRT1-PGC-1α signaling pathway. Additionally, the cartilage-targeting property of peptide-modified nanocarrier could be monitored via Magnetic Resonance (MR) and IVIS imaging. More significantly, RB@MPMW effectively delayed cartilage degeneration in ACLT rat model. Overall, our findings indicated that the as-prepared dual-drug delivery nanoplatform exerted potent anti-inflammation and anti-apoptotic effects, rescued energy metabolism of chondrocytes in vitro and prevented cartilage degeneration in vivo, which thereby showed positive performance for OA therapy.

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Collagen type II-targeting peptide and positive surface potential endow RB@MPMW with a fine cartilage affinity ability.

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RB@MPMW possess superb biological functions of scavenging free radicals and autophagy induction.

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RB@MPMW effectively promotes chondrocyte mitochondrial energy metabolism in the inflammatory microenvironment.

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RB@MPMW has a good MR imaging ability, which could monitor its therapeutic effects in vivo.

Esculentosides: Insights into the potential health benefits, mechanisms of action and molecular targets

BACKGROUND

Esculentosides and related phytolaccosides form a group of oleanene-type saponins isolated from plants of the Phytolaccaceae family, essentially Phytolacca esculenta, P. americana and P. acinosa. This chemical family offers a diversity of glycosylated compounds, including molecules with a mono-, di- or tri-saccharide unit at position C-3, and with or without a glucose residue at position C-28. The esculentosides, which derive essentially from the sapogenin jaligonic acid or its 30-methyl ester phytolaccagenin, exhibit anti-inflammatory, antifungal and anticancer activities.

PURPOSE

The objective of the review was to identify the 26 esculentosides (ES) and phytolaccosides known to date, including 16 monodesmosidic and 10 bidesmosidic saponins, and to review their pharmacological properties and molecular targets.

METHODOLOGY

The retrieval of potentially relevant studies was done by systematically searching of scientific databases like Google Scholar and PubMed in January-May 2020. The main keywords used as search terms were related to esculentosides, phytolaccosides and Phytolaccaceae. The systematic search retrieved about 110 papers that were potentially relevant and after an abstract-based selection, 68 studies were analyzed in details and discussed.

RESULTS

The structural relationship between the compounds and their sapogenin precursors has been studied. In addition, the pharmacological properties of the main ES, such as ES-A, -B and -H, have been analyzed to highlight their mode of action and potential targets. ES-A is a potent inhibitor of the release of cytokines and this anti-inflammatory activity contributes to the anticancer effects observed in vitro and in vivo. Potential molecular targets of ES-A/B include the enzymes cyclooxygenase 2 (COX-2) and casein kinase 2 (CK2). In addition, the targeting of the protein high-mobility group box 1 (HGMB1) by ES-A/B is proposed, based on molecular modeling and the structural analogy with the related saponin glycyrrhizin, a potent HGMB1 alarmin inhibitor.

CONCLUSION

More work is needed to properly characterize the molecular targets but otherwise compounds like ES-A and ES-H emerge as potent anti-inflammatory and anticancer agents and ES-B as an antifungal agent. A preclinical development of these three compounds should be considered.

Treatment repurposing for inflammatory bowel disease using literature-related discovery and innovation

Inflammatory bowel disease (IBD) incidence has been increasing steadily, most dramatically in the Western developed countries. Treatment often includes lifelong immunosuppressive therapy and surgery. There is a critical need to reduce the burden of IBD and to discover medical therapies with better efficacy and fewer potential side-effects. Repurposing of treatments originally studied in other diseases with similar pathogenesis is less costly and time intensive than de novo drug discovery. This study used a treatment repurposing methodology, the literature-related discovery and innovation (LRDI) text mining system, to identify potential treatments (developed for non-IBD diseases) with sufficient promise for extrapolation to treatment of IBD. By searching for desirable patterns of twenty key biomarkers relevant to IBD (e.g., inflammation, reactive oxygen species, autophagy, barrier function), the LRDI-based query retrieved approximately 9500 records from Medline. The most recent 350 records were further analyzed for proof-of-concept. Approximately 18% (64/350) met the criteria for discovery (not previously studied in IBD human or animal models) and relevance for application to IBD treatment. Many of the treatments were compounds derived from herbal remedies, and the majority of treatments were being studied in cancer, diabetes, and central nervous system disease, such as depression and dementia. As further validation of the search strategy, the query identified ten treatments that have just recently begun testing in IBD models in the last three years. Literature-related discovery and innovation text mining contains a unique search strategy with tremendous potential to identify treatments for repurposing. A more comprehensive query with additional key biomarkers would have retrieved many thousands more records, further increasing the yield of IBD treatment repurposing discovery.