Overexpression of acetyl CoA carboxylase β exacerbates podocyte injury in the kidney of streptozotocin-induced diabetic mice

Baihu Jia Renshen Decoction may improve skeletal muscle and adipose tissue functions of type I diabetic rats by affecting pancreatic β-cell function

BACKGROUND

Baihu Jia Renshen Decoction (BJRD) is used for diabetes mellitus (DM) management in clinics.

OBJECTIVE

To elucidate the potential mechanism of BJRD in treating type 1 DM (T1DM).

METHODS

T1DM models were established via intraperitoneal injection of streptozotocin (STZ). Rats were subsequently randomly divided into the normal control (NC), model (MOD), insulin (INS), INS + BJRD-medium dose (MID), and INS + BJRD-high dose (HIGH) groups. The rats' body weight was measured. Transcriptome sequencing was performed to detect differentially expressed genes (DEGs) in the muscle and adipose tissues. Quantitative real-time polymerase chain reaction was utilized to verify the DEG levels.

RESULTS

Body weights of MOD, INS, MID, and HIGH groups were significantly reduced as compared to those of NC group. Compared with NC group, MOD group showed significant Hspa1b and Notch3 downregulation and Camkk2 level elevation. Compared with MOD group, INS group showed further downregulation of the Hspa1b level, whereas MID group exhibited an increase. The Camkk2 levels in INS, MID, and HIGH groups were further reduced. The Notch3 levels did not significantly change in INS and MID groups, whereas that of HIGH group increased. Additionally, compared with NC group, MOD group demonstrated upregulation of the Myl1, Mylpf, Acacb, and Pygm levels and downregulation of Fasn level. Compared with MOD group, Myl1, Mylpf, and Pygm levels in INS, MID, and HIGH groups were down-regulated, whereas Fasn and Acacb levels were up-regulated.

CONCLUSION

BJRD may influence pancreatic β-cell function, thereby enhancing the function of the skeletal muscle and adipose tissues in a T1DM rat model.

Acetyl Co-A Carboxylase Inhibition Halts Hyperglycemia Induced Upregulation of De Novo Lipogenesis in Podocytes and Proximal Tubular Cells

The effect of glycemic stress on de novo lipogenesis (DNL) in podocytes and tubular epithelial cells is understudied. This study is aimed (A) to show the effect of glycemic stress on DNL, and (B) to assess the effect of acetyl-Co A (ACC) inhibition on halting upregulation of DNL, on the expression of other lipid regulatory genes in the DNL pathway, and on markers of fibrosis and apoptosis in podocytes and tubular epithelial cells. We used cultured mouse primary tubular epithelial cells, mouse proximal tubular (BUMPT) cells, and immortal mouse podocytes and measured their percentage of labeled 13C2-palmitate as a marker of DNL after incubation with 13C2 acetate in response to high glucose concentration (25 mM). We then tested the effect of ACC inhibition by complimentary strategies utilizing CRISPR/cas9 deletion or incubation with Acaca and Acacb GapmeRs or using a small molecule inhibitor on DNL under hyperglycemic concentration. Exposure to high glucose concentration (25 mM) compared to osmotic controlled low glucose concentration (5.5 mM) significantly increased labeled palmitate after 24 h up to 72 h in podocytes and primary tubular cells. Knocking out of the ACC coding Acaca and Acacb genes by CRISPR/cas9, downregulation of Acaca and Acacb by specific antisense LNA GapmeRs and inhibition of ACC by firsocostat similarly halted/mitigated upregulation of DNL and decreased markers of fibrosis and programmed cell death in podocytes and various tubular cells. ACC inhibition is a potential therapeutic target to mitigate or halt hyperglycemia-induced upregulation of DNL in podocytes and tubular cells.

Depletion of protein kinase STK25 ameliorates renal lipotoxicity and protects against diabetic kidney disease

Diabetic kidney disease (DKD) is the most common cause of severe renal disease worldwide and the single strongest predictor of mortality in diabetes patients. Kidney steatosis has emerged as a critical trigger in the pathogenesis of DKD; however, the molecular mechanism of renal lipotoxicity remains largely unknown. Our recent studies in genetic mouse models, human cell lines, and well-characterized patient cohorts have identified serine/threonine protein kinase 25 (STK25) as a critical regulator of ectopic lipid storage in several metabolic organs prone to diabetic damage. Here, we demonstrate that overexpression of STK25 aggravates renal lipid accumulation and exacerbates structural and functional kidney injury in a mouse model of DKD. Reciprocally, inhibiting STK25 signaling in mice ameliorates diet-induced renal steatosis and alleviates the development of DKD-associated pathologies. Furthermore, we find that STK25 silencing in human kidney cells protects against lipid deposition, as well as oxidative and endoplasmic reticulum stress. Together, our results suggest that STK25 regulates a critical node governing susceptibility to renal lipotoxicity and that STK25 antagonism could mitigate DKD progression.

Chinese Herbal Medicine in Ameliorating Diabetic Kidney Disease via Activating Autophagy

Diabetic kidney disease (DKD), a leading cause of end-stage renal disease (ESRD), has become a serious public health problem worldwide and lacks effective therapies due to its complex pathogenesis. Recent studies suggested defective autophagy involved in the pathogenesis and progression of DKD. Chinese herbal medicine, as an emerging option for the treatment of DKD, could improve diabetic kidney injury by activating autophagy. In this review, we briefly summarize underlying mechanisms of autophagy dysregulation in DKD, including AMP-activated protein kinase (AMPK), the mechanistic target of rapamycin (mTOR), and the sirtuin (Sirt) pathways, and we particularly concentrate on the current status of Chinese herbal medicine treating DKD by regulating autophagy. The advances in our understanding regarding the treatment of DKD via regulating autophagy with Chinese herbal medicine will enhance the clinical application of Chinese medicine as well as discovery of novel therapeutic agents for diabetic patients.