ABSTRACT
Senescence-accelerated mouse prone 8 (SAMP8) mice exhibit cognitive defects and neuron loss with aging, and were used to study anti-aging effects of Dendrobium nobile alkaloids (DNLA). DNLA (20 and 40 mg/kg) were orally administered to SAMP8 mice from 6 to 10 months of age. At 10-month of age, behavioral tests via Y-maze and Open-field and neuron damage via Nissl staining were evaluated. Protein was extracted and subjected to phosphorylated proteomic analysis followed by bioinformatic analysis. The cognitive deficits and neuron loss in hippocampus and cortex of aged SAMP8 mice were improved by DNLA. Hippocampal proteomic analysis revealed 196 differentially expressed protein/genes in SAMP8 compared to age-matched senescence-accelerated resistant SAMR1 mice. Gene Oncology enriched the tubulin binding, microtubule binding, and other activities. Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed endocytosis, mRNA surveillance, tight junction, protein processing in endoplasmic reticulum, aldosterone synthesis and secretion, and glucagon signaling pathway changes. Upregulated protein/genes in the hippocampus of SAMP8 mice, such as Lmtk3, Usp10, Dzip1, Csnk2b, and Rtn1, were attenuated by DNLA; whereas downregulated protein/genes, such as Kctd16, Psd3, Bsn, Atxn2l, and Kif1a, were rescued by DNLA. The aberrant protein/gene expressions of SAMP8 mice were correlated with transcriptome changes of Alzheimer's disease in the Gene Expression Omnibus (GEO) database, and the scores were attenuated by DNLA. Thus, DNLA improved cognitive dysfunction and ameliorated neuronal injury in aged SAMP8 mice, and attenuated aberrant protein/gene expressions.
Subject(s)
Alkaloids , Alzheimer Disease , Dendrobium , Mice , Animals , Proteomics , Alkaloids/pharmacology , Aging , Alzheimer Disease/drug therapy , Alzheimer Disease/genetics , HippocampusABSTRACT
Foot process effacement is an important feature of early diabetic nephropathy (DN), which is closely related to the development of albuminuria. Under certain nephrotic conditions, the integrity and function of the glomerular slit diaphragm (SD) structure were impaired and replaced by the tight junction (TJ) structure, resulting in so-called SD-TJ transition, which could partially explain the effacement of foot processes at the molecular level. However, the mechanism underlying the SD-TJ transition has not been described in DN. Here, we demonstrated that impaired autophagic flux blocked p62-mediated degradation of ZO-1 (TJ protein) and promoted podocytes injury via activation of caspase3 and caspase8. Interestingly, the expression of VDR in podocytes was decreased under diabetes conditions, which impaired autophagic flux through downregulating Atg3. Of note, we also found that VDR abundance was negatively associated with impaired autophagic flux and SD-TJ transition in the glomeruli from human renal biopsy samples with DN. Furthermore, VDR activation improved autophagic flux and attenuated SD-TJ transition in the glomeruli of diabetic animal models. In conclusion, our data provided the novel insight that VDR/Atg3 axis deficiency resulted in SD-TJ transition and foot processes effacement via blocking the p62-mediated autophagy pathway in DN.
Subject(s)
Autophagy-Related Proteins/metabolism , Autophagy/physiology , Diabetic Nephropathies/metabolism , RNA-Binding Proteins/metabolism , Receptors, Calcitriol/metabolism , Ubiquitin-Conjugating Enzymes/metabolism , Animals , Autophagy-Related Proteins/genetics , Bone Density Conservation Agents/pharmacology , Caspase 3/genetics , Caspase 3/metabolism , Caspase 8/genetics , Caspase 8/metabolism , Cells, Cultured , Diabetic Nephropathies/pathology , Down-Regulation , Ergocalciferols/pharmacology , Gene Expression Regulation/drug effects , Humans , Kidney/cytology , Kidney Glomerulus/metabolism , Mice , Mice, Inbred NOD , Podocytes/metabolism , RNA-Binding Proteins/genetics , Random Allocation , Rats , Rats, Sprague-Dawley , Receptors, Calcitriol/agonists , Receptors, Calcitriol/deficiency , Receptors, Calcitriol/genetics , Tight Junctions , Ubiquitin-Conjugating Enzymes/genetics , Zonula Occludens-1 Protein/genetics , Zonula Occludens-1 Protein/metabolismABSTRACT
BACKGROUND: Dendrobium nobile is a well-known traditional Chinese herbal medicine used for age-related diseases. Dendrobium nobile Lindl. alkaloid (DNLA) is the active ingredient to improve learning and memory deficits in laboratory animals. OBJECTIVE: The aim of the present study was to examine the anti-aging effects of long-term administration of DNLA and metformin during the aging process in senescence-accelerated mouse-prone 8 (SAMP8) mice. METHODS: SAMP8 mice were orally given DNLA (20 and 40âmg/kg) or metformin (80âmg/kg) starting at 6 months of age until 12 months of age. Age-matched SAMR1 mice were used as controls. DNLA and metformin treatments ameliorated behavioral deficits of 12-month-old SAMP8 mice, as determined by Rotarod, Y-maze, and Open-field tests. RESULTS: DNLA and metformin treatments prevented brain atrophy and improved morphological changes in the hippocampus and cortex, as evidenced by Nissl and H&E staining for neuron damage and loss, and by SA-ß-gal staining for aging cells. DNLA and metformin treatments decreased amyloid-ß1-42, AßPP, PS1, and BACE1, while increasing IDE and neprilysin for Aß clearance. Furthermore, DNLA and metformin enhanced autophagy activity by increasing LC3-II, Beclin1, and Klotho, and by decreasing p62 in the hippocampus and cortex. CONCLUSION: The beneficial effects of DNLA were comparable to metformin in protecting against aging-related cognitive deficits, neuron aging, damage, and loss in SAMP8 mice. The mechanisms could be attributed to increased Aß clearance, activation of autophagy activity, and upregulation of Klotho.
