Bisacurone attenuates diabetic nephropathy by ameliorating oxidative stress, inflammation and apoptosis in rats

HDAC6 promotes inflammation in lupus nephritis mice by regulating transcription factors MAFF and KLF5 in renal fibrosis

AIM

This study explored the effect and mechanism of MAFF and HDAC6 on renal fibrosis and inflammation in lupus nephritis (LN).

METHODS

IL-33 treated renal epithelial cells and MRL/lpr mice were respectively used for in vitro and in vivo experiments. The expressions of HDAC6, MAFF, and KLF5 were measured in cells and renal tissues. Before and after cell transfection, the morphological changes in renal tissues were observed using Hematoxylin and eosin (H&E) and Masson staining. The proteinuria, serum creatinine (SCr), blood urea nitrogen (BUN), and double-stranded DNA (dsDNA) levels were detected by biochemical analysis. The expressions of fibrosis and inflammation related proteins (including α-SMA, Vimentin, IL-1β, IL-6, and TNF-α), p65, and iNOS were also detected. The relationship among MAFF, HDAC6, and KLF5 was determined by chromatin immunoprecipitation and dual luciferase reporter gene assay.

RESULTS

Renal tissues and cell models had elevated expressions of HDAC6 and KLF5, and decreased MAFF expression. HDAC6 suppression or MAFF overexpression led to suppression of proteinuria, SCr, BUN, and dsDNA levels, as well as attenuation of inflammatory infiltration and collagen deposition. HDAC6 can suppress MAFF expression via deacetylation to abolish its suppression of KLF5 expression, thus increasing KLF5 expression. In vivo and in vitro experiments showed the suppressive effect of HDAC6 suppression on renal fibrosis and inflammation can be abolished by KLF5 overexpression.

CONCLUSION

HDAC6 suppresses MAFF expression via deacetylation to elevate KLF5 expression, which consequently enhances fibrosis and inflammatory response in LN.

Therapeutic Effects of Liposomal Resveratrol in the Mitigation of Diabetic Nephropathy via Modulating Inflammatory Response, Oxidative Stress, and Apoptosis

An important factor in the development of diabetes and its associated consequences is prolonged chronic hyperglycemia, which weakens the antioxidant defense system and produces reactive oxygen species. Phytochemicals have been found to scavenge free radicals and exhibit antioxidant effects necessary to increase insulin sensitivity and reduce the development of diabetes-related complications. Current treatments for managing diabetes and diabetic nephropathy are often not very effective and come with several limitations and side effects. Resveratrol, for example, has shown therapeutic potential in mitigating kidney damage induced by high glucose levels, but its short bioavailability is a significant limitation. This accentuates the need for alternatives that not only improve the disease but also reduce the side effects associated with treatment. To enhance the therapeutic efficacy of resveratrol, we investigated the protective effects of liposomal resveratrol (LR) in a streptozotocin-induced diabetic rat model at doses of 20 and 40 mg/kg. We compared the impact of LR to that of resveratrol alone (at a dose of 40 mg/kg) on various parameters, including serum levels of biochemical markers, tissue levels of pro-inflammatory cytokines, nuclear transcription factor, oxidative stress indices, and apoptotic markers. LR, as a highly absorbable and metabolized form of resveratrol, has demonstrated beneficial effects in diabetic rats. Administered at both 20 mg/kg and 40 mg/kg dosages over a 5-week period, it demonstrated notable efficacy in alleviating inflammation. This was accomplished by diminishing the levels of pro-inflammatory mediators, TNF-α and IL-6, through the inhibition of NF-κB translocation. Additionally, LR influenced apoptotic markers, specifically caspase, BCL-2, and BAX. Furthermore, it enhanced the expression of key antioxidant enzymes such as catalase and glutathione peroxidase while significantly lowering malondialdehyde levels. These significant biochemical and immunological protective effects correlated with improved histological integrity and overall kidney architecture. Notably, resveratrol alone was not as effective as LR in restoring kidney function, highlighting its potential as a therapeutic candidate for the treatment of diabetic nephropathy. However, more in-depth studies are needed to explore its mechanism of action and improved bioavailability.

Exosomes as nanostructures deliver miR-204 in alleviation of mitochondrial dysfunction in diabetic nephropathy through suppressing methyltransferase-like 7A-mediated CIDEC N6-methyladenosine methylation

OBJECTIVE

The exosomal cargo mainly comprises proteins, lipids, and microRNAs (miRNAs). Among these, miRNAs undertake multiple biological effects of exosomes (Exos). Some stem cell-derived exosomal miRNAs have shown the potential to treat diabetic nephropathy (DN). However, there is little research into the therapeutic effects of adipose-derived stem cell (ADSC)-derived exosomal miRNAs on DN. We aimed to explore the potential of miR-204-modified ADSC-derived Exos to mitigate DN.

METHODS

Exos were extracted and identified from ADSCs. Histopathological injury, oxidative stress (OS), mitochondrial function, cell viability, and apoptosis were assessed to explore the effects of ADSC-derived Exos on DN. For mechanism exploration, quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to measure miR-204, methyltransferase (METTL3, METTL14, and METTL7A), and CIDEC. Also, CIDEC m6A methylation and miR-204-METTL7A, and METTL7A-CIDEC interactions were determined.

RESULTS

Initially, OS-induced mitochondrial dysfunction was observed in DN rats. ADSC-derived Exos inhibited histopathological injury, cell apoptosis, OS, and mitochondrial dysfunction in DN rats. The similar therapeutic effects of ADSC-derived Exos were detected in the in vitro model. Intriguingly, miR-204 was released by ADSC-derived Exos and its upregulation enhanced the anti-DN effects of Exos. Mechanically, miR-204 reduced METTL7A expression to CIDEC m6A methylation, thus suppressing OS and mitochondrial dysfunction.

CONCLUSIONS

ADSC-derived exosomal miR-204 rescued OS-induced mitochondrial dysfunction by inhibiting METTL7A-mediated CIDEC m6A methylation. This study first revealed the significant role of ADSC-derived exosomal miR-204 in DN, paving the way for the development of novel therapeutic strategies to improve the clinical outcomes of DN patients.

Bisacurone gel ameliorated burn wounds in experimental rats via its anti-inflammatory, antioxidant, and angiogenic properties

PURPOSE

To investigate putative mechanism of wound healing for chitosan-based bisacurone gel against secondary burn wounds in rats.

METHODS

A second-degree burn wound with an open flame using mixed fuel (2 mL, 20 seconds) was induced in Sprague Dawley rats (male, 180-220 g, n = 15, each) followed by topical treatments with either vehicle control (white petroleum gel, 1%), silver sulfadiazine (1%) or bisacurone gel (2.5, 5, or 10%) for 20 days. Wound contraction rate and paw withdrawal threshold were monitored on various days. Oxidative stress (superoxide dismutase, glutathione, malondialdehyde, and nitric oxide), pro-inflammatory cytokines (tumour necrosis factor-alpha, interleukins by enzyme-linked immunosorbent assay), growth factors (transforming growth factor-β, vascular endothelial growth factor C using real time polymerase chain reaction and Western blot assay) levels, and histology of wound skin were assessed at the end.

RESULTS

Bisacurone gel showed 98.72% drug release with a 420.90-442.70 cps viscosity. Bisacurone gel (5 and 10%) significantly (p < 0.05) improved wound contraction rate and paw withdrawal threshold. Bisacurone gel attenuated oxidative stress, pro-inflammatory cytokines, and water content. It also enhanced angiogenesis (hydroxyproline and growth factor) and granulation in wound tissue than vehicle control.

CONCLUSIONS

These findings suggested that bisacurone gel can be a potential candidate to treat burn wounds via its anti-inflammatory, antioxidant, and angiogenic properties.

Hypolipidemic and Anti-Inflammatory Effects of Curcuma longa-Derived Bisacurone in High-Fat Diet-Fed Mice

Turmeric (Curcuma longa) contains various compounds that potentially improve health. Bisacurone is a turmeric-derived compound but has been less studied compared to other compounds, such as curcumin. In this study, we aimed to evaluate the anti-inflammatory and lipid-lowering effects of bisacurone in high-fat diet (HFD)-fed mice. Mice were fed HFD to induce lipidemia and orally administered bisacurone daily for two weeks. Bisacurone reduced liver weight, serum cholesterol and triglyceride levels, and blood viscosity in mice. Splenocytes from bisacurone-treated mice produced lower levels of the pro-inflammatory cytokines IL-6 and TNF-α upon stimulation with a toll-like receptor (TLR) 4 ligand, lipopolysaccharide (LPS), and TLR1/2 ligand, Pam3CSK4, than those from untreated mice. Bisacurone also inhibited LPS-induced IL-6 and TNF-α production in the murine macrophage cell line, RAW264.7. Western blot analysis revealed that bisacurone inhibited the phosphorylation of IKKα/β and NF-κB p65 subunit, but not of the mitogen-activated protein kinases, p38 kinase and p42/44 kinases, and c-Jun N-terminal kinase in the cells. Collectively, these results suggest that bisacurone has the potential to reduce serum lipid levels and blood viscosity in mice with high-fat diet-induced lipidemia and modulate inflammation via inhibition of NF-κB-mediated pathways.