Isoeucommin A attenuates kidney injury in diabetic nephropathy through the Nrf2/HO-1 pathway

Inhibitory effect of Incarvillea diffusa Royle extract in the formation of calcium oxalate nephrolithiasis by regulating ROS-induced Nrf2/HO-1 pathway in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Calcium oxalate (CaOx) kidney stones are widely acknowledged as the most prevalent type of urinary stones, with high incidence and recurrence rates. Incarvillea diffusa Royle (ID) is a traditionally used medicinal herb in the Miao Minzu of Guizhou province, China, for treating urolithiasis. However, the active components and the underlying mechanism of its pharmacodynamic effects remain unclear.

AIM OF THE STUDY

This study aimed to investigate the potential inhibitory effect of the active component of ID on the formation of CaOx nephrolithiasis and elucidate the underlying mechanism.

MATERIALS AND METHODS

In vivo, a CaOx kidney stone model was induced in Sprague-Dawley (SD) rats using an ethylene glycol and ammonium chloride protocol for four weeks. Forty-eight male SD rats were randomly assigned to 6 groups (n = 8): blank group, model group, apocynin group, and low, medium, and high dose of ID's active component (IDW) groups. After three weeks of administration, rat urine, serum, and kidney tissues were collected. Renal tissue damage and crystallization, Ox, BUN, Ca2+, CRE, GSH, MDA, SOD contents, and levels of IL-1β, IL-18, MCP-1, caspase-1, IL-6, and TNF-α in urine, serum, and kidney tissue were assessed using HE staining and relevant assay kits, respectively. Protein expression of Nrf2, HO-1, p38, p65, and Toll-4 in kidney tissues was quantified via Western blot. The antioxidant capacities of major compounds were evaluated through DPPH, O2·-, and ·OH radical scavenging assays, along with their effects on intracellular ROS production in CaOx-induced HK-2 cells.

RESULTS

We found that IDW could significantly reduce the levels of CRE, GSH, MDA, Ox, and BUN, and enhancing SOD activity. Moreover, it could inhibit the secretion of TNF-α, IL-1β, IL-18, MCP-1, caspase-1, and decreased protein expression of Nrf2, HO-1, p38, p65, and Toll-4 in renal tissue. Three major compounds isolated from IDW exhibited promising antioxidant activities and inhibited intracellular ROS production in CaOx-induced HK-2 cells.

CONCLUSIONS

IDW facilitated the excretion of supersaturated Ca2+ and decreased the production of Ox, BUN in SD rat urine, and mitigated renal tissue damage by regulating Nrf2/HO-1 signaling pathway. Importantly, the three major compounds identified as active components of IDW contributed to the inhibition of CaOx nephrolithiasis formation. Overall, IDW holds significant potential for treating CaOx nephrolithiasis.

Moslae Herba: Botany, Traditional Uses, Phytochemistry, and Pharmacology

Moslae Herba (MH) can be used for both medicine and food and has a long history of medicine. MH has the effects of sweating and relieving the exterior, removing dampness and harmonizing, and is mainly used for colds caused by damp heat in summer. It is called "Xiayue Zhi Mahuang" in China. So far, 123 chemical compounds have been isolated and identified from MH, including flavonoids, terpenoids, phenolic acids, phenylpropanoids, and other chemical compounds. Its chemical components have a wide range of pharmacological activities, including antibacterial, antiviral, anti-inflammatory, antioxidant, analgesic sedation, antipyretic, immune regulation, insecticidal, and other effects. In addition, because of its aromatic odor and health care function, MH also has development and utilization value in food, chemical, and other fields. This paper reviewed the research progress of MH in botany, traditional uses, phytochemistry, and pharmacology and provided a possible direction for further research.

A review of "plant gold" Eucommia ulmoides Oliv.: A medicinal and food homologous plant with economic value and prospect

Eucommia ulmoides Oliv. is an ancient and precious plant that has been used as medicine in China for more than 2000 years. Because its bark, leaves, seeds, and male flowers can be used in medicine, it plays an important role in medicine, food, chemical industry, and other fields, so it is also called "plant gold". 246 compounds have been isolated from E. ulmoides, which endow E. ulmoides with many unique pharmacological effects and make it wide to study in the fields of osteoporosis, hypertension, liver protection, and so on. Besides, E. ulmoides also has significant medicinal effects on anti-inflammatory, antioxidant, immunomodulation, and neuroprotection, and is often used in clinical compound medicines of traditional Chinese medicine. In addition to updating its ethnobotany, phytochemistry, pharmacology, and toxicology information, the economic botany of leaves, seeds, and male flowers was also introduced. It hopes hoping to fully understand this economically important Chinese medicine and provide a scientific basis for further development and utilization of E. ulmoides.

Nrf2 signaling in diabetic nephropathy, cardiomyopathy and neuropathy: Therapeutic targeting, challenges and future prospective

Western lifestyle contributes to an overt increase in the prevalence of metabolic anomalies including diabetes mellitus (DM) and obesity. Prevalence of DM is rapidly growing worldwide, affecting many individuals in both developing and developed countries. DM is correlated with the onset and development of complications with diabetic nephropathy (DN), diabetic cardiomyopathy (DC) and diabetic neuropathy being the most devastating pathological events. On the other hand, Nrf2 is a regulator for redox balance in cells and accounts for activation of antioxidant enzymes. Dysregulation of Nrf2 signaling has been shown in various human diseases such as DM. This review focuses on the role Nrf2 signaling in major diabetic complications and targeting Nrf2 for treatment of this disease. These three complications share similarities including the presence of oxidative stress, inflammation and fibrosis. Onset and development of fibrosis impairs organ function, while oxidative stress and inflammation can evoke damage to cells. Activation of Nrf2 signaling significantly dampens inflammation and oxidative damage, and is beneficial in retarding interstitial fibrosis in diabetic complications. SIRT1 and AMPK are among the predominant pathways to upregulate Nrf2 expression in the amelioration of DN, DC and diabetic neuropathy. Moreover, certain therapeutic agents such as resveratrol and curcumin, among others, have been employed in promoting Nrf2 expression to upregulate HO-1 and other antioxidant enzymes in the combat of oxidative stress in the face of DM.

Insights into the Molecular Mechanisms of NRF2 in Kidney Injury and Diseases

Redox is a constant phenomenon in organisms. From the signaling pathway transduction to the oxidative stress during the inflammation and disease process, all are related to reduction-oxidation (redox). Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor targeting many antioxidant genes. In non-stressed conditions, NRF2 maintains the hemostasis of redox with housekeeping work. It expresses constitutively with basal activity, maintained by Kelch-like-ECH-associated protein 1 (KEAP1)-associated ubiquitination and degradation. When encountering stress, it can be up-regulated by several mechanisms to exert its anti-oxidative ability in diseases or inflammatory processes to protect tissues and organs from further damage. From acute kidney injury to chronic kidney diseases, such as diabetic nephropathy or glomerular disease, many results of studies have suggested that, as a master of regulating redox, NRF2 is a therapeutic option. It was not until the early termination of the clinical phase 3 trial of diabetic nephropathy due to heart failure as an unexpected side effect that we renewed our understanding of NRF2. NRF2 is not just a simple antioxidant capacity but has pleiotropic activities, harmful or helpful, depending on the conditions and backgrounds.

Translocator protein alleviates allodynia and improves Schwann cell function against diabetic peripheral neuropathy via activation of the Nrf2-dependent antioxidant system and promoting autophagy

AIMS

In diabetes, autophagy and the nuclear factor erythroid-derived-2-like 2 (Nrf2)-dependent antioxidant system are impaired. Translocator protein (TSPO) agonist Ro5-4864 alleviates neuropathic pain, including diabetic peripheral neuropathy (DPN). However, the precise mechanisms remain unclear. Thus, we investigated the effects of Ro5-4864 on autophagy and the Nrf2-dependent antioxidant system in the sciatic nerves of DPN rats.

METHODS

All rats were randomly assigned to Sham or DPN group. After type 2 diabetes modelling (established by high-fat diet and streptozotocin injection) followed by behavioural tests, established DPN rats were randomly assigned to the DPN group, the Ro (TSPO agonist Ro5-4864) group, the Ro + 3-MA (autophagy inhibitor) group and the Ro + ML385 (Nrf2 inhibitor) group. Behavioural assessments were performed at baseline, on days 3, 7, 14, 21 and 28. Sciatic nerves were collected on day 28 for immunofluorescence, morphological and western blot analyses.

RESULTS

Ro5-4864 alleviated allodynia and increased myelin sheath thickness and myelin protein expression after DPN. Beclin-1 (p < 0.01) and LC3-II/LC3-I ratio (p < 0.01) decreased and p62 (p < 0.01) accumulated in the DPN rats. Ro5-4864 administration increased the Beclin-1 and LC3-II/LC3-I ratio and decreased p62 accumulation. Furthermore, nuclear Nrf2 contents (p < 0.01) and cytoplasmic HO-1 (p < 0.01) and NQO1 (p < 0.01) expressions were significantly inhibited in the DPN rat, which was also improved by Ro5-4864. All the beneficial effects were abrogated by 3-MA or ML385.

CONCLUSION

TSPO exhibited a potent analgesic effect and improved Schwann cell function and regeneration against DPN by activating the Nrf2-dependent antioxidant system and promoting autophagy.

Lignans as Pharmacological Agents in Disorders Related to Oxidative Stress and Inflammation: Chemical Synthesis Approaches and Biological Activities

Plant lignans exhibit a wide range of biological activities, which makes them the research objects of potential use as therapeutic agents. They provide diverse naturally-occurring pharmacophores and are available for production by chemical synthesis. A large amount of accumulated data indicates that lignans of different structural groups are apt to demonstrate both anti-inflammatory and antioxidant effects, in many cases, simultaneously. In this review, we summarize the comprehensive knowledge about lignan use as a bioactive agent in disorders associated with oxidative stress and inflammation, pharmacological effects in vitro and in vivo, molecular mechanisms underlying these effects, and chemical synthesis approaches. This article provides an up-to-date overview of the current data in this area, available in PubMed, Scopus, and Web of Science databases, screened from 2000 to 2022.