The effects of the water-extraction of Astragali Radix and Lycopi herba on the Pathway of TGF-smads-UPP in a rat model of Diabetic Nephropathy

CKIP-1 affects the polyubiquitination of Nrf2 and Keap1 via mediating Smurf1 to resist HG-induced renal fibrosis in GMCs and diabetic mice kidneys

Our previous study indicated that Casein kinase 2 interacting protein-1 (CKIP-1) could promote the activation of the nuclear factor E2-related factor 2 (Nrf2)/ antioxidant response element (ARE) pathway, playing a significant role in inhibiting the fibrosis of diabetic nephropathy (DN). However, the underlying mechanism is still unknown. Here, we investigated whether CKIP-1 affects the polyubiquitination of Nrf2 and its cytosolic inhibitor kelch like ECH-associated protein 1 (Keap1) via mediating Smad ubiquitylation regulatory factor-1 (Smurf1) to promote the activation of the Nrf2/ARE signaling and resist high glucose (HG)-induced renal fibrosis in glomerular mesangial cells (GMCs) and diabetic mice kidneys. Results showed that the expression of Smurf1 increased in HG-induced GMCs, with a paramount upregulation at 1h. Overexpression of wild-type Smurf1 plasmid further promoted the HG-induced the over-production of fibronectin (FN) and intercellular adhesionmolecule-1 (ICAM-1), and depletion of Smurf1 dramatically reduced the expression of FN and ICAM-1. Overexpression of CKIP-1 decreased the K48-linked polyubiquitination and increased the K63-linked polyubiquitination of Nrf2 as well as enhanced the K48-linked polyubiquitination and reduced K63-linked polyubiquitination of Keap1, promoting the activation of the Nrf2/ARE pathway. Overexpression of Smurf1 increased the K48-linked polyubiquitination and decreased the K63-linked polyubiquitination of Nrf2, and down-regulated the K48-linked polyubiquitination and up-regulated the K63-linked polyubiquitination of Keap1, inhibiting the activation of the Nrf2/ARE pathway. CKIP-1 promoted the degradation of Smurf1 by increasing the ubiquitination of Smurf1. Treatment of CKIP-1 adenovirus infection reduced the Smurf1 levels, promoted the activation of the Nrf2/ARE pathway as well as suppressed the production of reactive oxygen species (ROS), and then improved the failure of renal function of diabetic mice. Experiments above suggested that CKIP-1 affects the polyubiquitination of Nrf2 and Keap1 and promotes the Nrf2-ARE pathway through down-regulating Smurf1 to resist HG-induced up-regulation of FN and ICAM-1 in GMCs and diabetic mice kidneys.

Radix Puerariae and Fructus Crataegi mixture inhibits renal injury in type 2 diabetes via decreasing of AKT/PI3K

Background

Radix puerariae (RP) is a herbal medicines for diabetes, mainly because of anti-oxidative, insulin resistance and hypoglycemic effect. Fructus crataegi (FC) also possesses strong antioxidant activity in vitro. This study focused on the effects of herbal mixture of RP and FC (RPFC) on renal protection through a diabetic rat model.

Methods

Type 2 Diabetic model was established with high fat diet followed by injecting rats a low dose of STZ (25 mg/kg body weight). Rats were randomly divided into five groups: normal, high fat diet, diabetes mellitus, high fat diet plus RPFC prevention, and RPFC prevention before diabetes mellitus. RPFC was given to rats daily by intragastric gavage. The blood bio-chemical index and renal pathological changes were examined. The later includes hematoxylin and eosin staining, periodic acid schiff staining, and Masson trichrome staining. Protein levels of were determined by Western blot and immunohistochemical staining. mRNA levels were detected by RT-PCR.

Results

Rats prevented with RPFC resulted in decreasing blood glucose with corresponding vehicle treated rats. Glomerulus mesangial matrix expansion, renal capsule constriction, and renal tubular epithelial cell edema were less severe following RPFC prevention. Moreover, RPFC prevention reduced protein levels of PI3K, AKT, α-SMA and collagen IV in the kidney of diabetic rats.

Conclusion

Combined prevention with RPFC may inhibit the PI3K/AKT pathway in the kidney, thereby prevent renal injury in diabetic rats.

Using UPLC-MS/MS for Characterization of Active Components in Extracts of Yupingfeng and Application to a Comparative Pharmacokinetic Study in Rat Plasma after Oral Administration

Yupingfeng (YPF), a famous traditional Chinese medicine, which contains a large array of compounds, has been effectually used in health protection. A two-dimensional liquid chromatography (²D-LC) combined with quadrupole time-of-flight mass spectrometry (QTOF-MS) method was firstly established to separate and identify chemical components in YPF. A total of 33 compounds were identified, including 15 constituents (flavonoids and saponins) in Astragali radix; seven constituents (sesquiterpenoids and polysaccharide) in Atractylodis rhizoma; and 11 constituents (chromone and coumarins) in Saposhnikoviae radix. The corresponding fragmentation pathway of typical substances was investigated. Then, seven active constituents (astragaloside, calycosin, formononetin, cimicifugoside, 4-O-beta-d-glucosyl-5-O-methylvisamminol, sec-O-glucosylhamaudol, and atractylenolide II) derived from three medicinal plants were chosen to further investigate the pharmacokinetic behavior of YPF formula using ultrahigh-performance liquid chromatography with triple quadrupole mass spectrometry system. The method was sensitive, accurate and reliable. We also used the area under the plasma concentration-time curve from zero to infinity (AUC_0-∞) as weighting factor to make an integrated pharmacokinetic curve. Results show that the constituents of Saposhnikoviae radix have the best absorption and pharmacokinetic behavior and may play important role in leading to the changes of overall therapeutic effects of YPF. Further study is needed to confirm the association between them.

Tangzhiqing Granules Alleviate Podocyte Epithelial-Mesenchymal Transition in Kidney of Diabetic Rats

This study discussed the effect of Tangzhiqing granules on podocyte epithelial-mesenchymal transition in kidney of diabetic rats. The diabetic rats were divided randomly into five groups: DM group treated with vehicle, Tangzhiqing granules low-dose treatment group, Tangzhiqing granules middle-dose treatment group, and Tangzhiqing granules high-dose treatment group. Eight Wistar rats used as control group were given saline solution. The intervention was all intragastric administration for 8 weeks. At the end of the 8 weeks, biochemical parameters and kidney weight/body weight ratio were measured. The kidney tissues were observed under light microscope and transmission electron microscopy. To search for the underlying mechanism, we examined the epithelial-to-mesenchymal transition (EMT) related molecular markers and TGF-β/smad signaling pathway key proteins expression. The results showed that Tangzhiqing granules relieved the structural damage and functional changes of diabetic kidneys. Kidney podocyte EMT related molecular markers nephrin and CD2AP expression were increased, when desmin and α-SMA levels were decreased by Tangzhiqing granules in diabetic rats. Further TGF-β/smad signaling pathway key proteins TGF-β1 and p-smad2/3 levels were decreased in diabetic rats after treatment with Tangzhiqing granules. These findings suggest that Tangzhiqing granules may protect the podocytes of diabetic nephropathy rats via alleviating podocyte EMT and likely activating TGFβ/smad signaling pathway.

Bone Morphogenic Protein Type 2 Receptor Mutation-Independent Mechanisms of Disrupted Bone Morphogenetic Protein Signaling in Idiopathic Pulmonary Arterial Hypertension

Altered bone morphogenic protein (BMP) signaling, independent of BMPR2 mutations, can result in idiopathic pulmonary arterial hypertension (IPAH). Glucose dysregulation can regulate multiple processes in IPAH. However, the role of glucose in BMP antagonist expression in IPAH has not been characterized. We hypothesized that glucose uptake regulates BMP signaling through stimulation of BMP antagonist expression in IPAH. Using human plasma, lung tissue, and primary pulmonary arterial smooth muscle cells (PASMCs), we examined the protein expression of BMP2, BMP-regulated Smads, and Smurf-1 in patients with IPAH and control subjects. Gremlin-1 levels were elevated in patients with IPAH compared with control subjects, whereas expression of BMP2 was not different. We demonstrate increased Smad polyubiquitination in IPAH lung tissue and PASMCs that was further enhanced with proteasomal inhibition. Examination of the Smad ubiquitin-ligase, Smurf-1, showed increased protein expression in IPAH lung tissue and localization in the smooth muscle of the pulmonary artery. Glucose dose dependently increased Smurf-1 protein expression in control PASMCs, whereas Smurf-1 in IPAH PASMCs was increased and sustained. Conversely, phospho-Smad1/5/8 levels were reduced in IPAH compared with control PASMCs at physiological glucose concentrations. Interestingly, high glucose concentrations decreased phosphorylation of Smad1/5/8 in control PASMCs. Blocking glucose uptake had opposing effects in IPAH PASMCs, and inhibition of Smurf-1 activity resulted in partial rescue of Smad1/5/8 activation and cell migration rates. Collectively, these data suggest that BMP signaling can be regulated through BMPR2 mutation-independent mechanisms. Gremlin-1 (synonym: induced-in-high-glucose-2 protein) and Smurf-1 may function to inhibit BMP signaling as a consequence of the glucose dysregulation described in IPAH.

Astragaloside IV alleviates E. coli-caused peritonitis via upregulation of neutrophil influx to the site of infection

Astragaloside IV (AS-IV), an active saponin purified from Astragali Radix, has been identified with broad biological and pharmacological activities. In the present study, we continue to explore the potential effect of AS-IV on antibacterial response using an acute E. coli peritoneal infection model. Our findings implied that administration of AS-IV decreases mortality in mice challenged by lethal E. coli infection. The protection of AS-IV was related to promotion of neutrophil extravasation into the peritoneum and bacterial clearance. Toll-like receptor (TLR) activation in neutrophils has been reported to reduce CXCR2 expression and subsequent neutrophil migration. Our data indicated that AS-IV prevented the reduction of CXCR2 expression and neutrophil migration induced by LPS, the activator for TLR4. Moreover, we found that AS-IV blocks LPS-induced suppression of CXCR2 on neutrophils by inhibiting the expression of G protein-coupled receptor kinase-2 (GRK2), an agonist that regulates desensitization and internalization of chemokine receptors. Taken together, these data propose that AS-IV, through modulating GRK2-CXCR2 signal in neutrophils, offers an essential efficacy on host antibacterial immunity.

A novel herbal treatment reduces depressive-like behaviors and increases brain-derived neurotrophic factor levels in the brain of type 2 diabetic rats

BACKGROUND

Radix Puerariae and hawthorn fruit have been demonstrated to treat diabetes. They offer potential benefits for preventing depression in diabetes.

OBJECTIVE

The aim of this study was to investigate whether the combination of Radix Puerariae and hawthorn fruit (CRPHF) could prevent depression in a diabetic rat model generated by feeding the rats with a high-fat diet and a low-dose streptozotocin (STZ).

METHODS

The CRPHF was provided by the Shanghai Chinese Traditional Medical University. Twenty-four rats were randomly divided into four groups: normal control, normal-given-CRPHF (NC), diabetic control, and diabetic-given-CRPHF (DC) groups. The type 2 diabetic model was created by feeding the rats with a high-fat diet for 4 weeks followed by injection of 25 mg/kg STZ. CRPHF was given at 2 g/kg/d to the rats of NC and DC groups by intragastric gavage daily for 4 weeks after the type 2 diabetic model was successfully created. Body weight, random blood glucose (RBG), oral glucose tolerance test, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were measured during the study. Depressive-like behavior was evaluated at the end of the treatment by using the open field test (OFT), the elevated plus-maze test (EPMT), locomotor activity test (LAT), and forced swimming test (FST). Levels of extracellular signal-regulated protein kinase (ERK) and brain-derived neurotrophic factor (BDNF) in the prefrontal cortex were evaluated by using Western blot.

RESULTS

1) CRPHF reduced RBG and improved glucose tolerance in diabetic rats; 2) CRPHF reduced TC and TG but did not significantly change HDL-C or LDL-C in diabetic rats; 3) CRPHF reversed the loss in body weights observed in diabetic rats; 4) CRPHF reduced depressive-like behavior as measured by OFT, EPMT, LAT, and FST; 5) BDNF was upregulated, and ERK was activated in the prefrontal cortex of diabetic rats treated with CRPHF.

CONCLUSION

CRPHF has the potential of preventing depression in patients with diabetes.