scholarly journals Overexpression of cGMP-dependent protein kinase I (PKG-I) attenuates ischemia-reperfusion-induced kidney injury

2012 ◽  
Vol 302 (5) ◽  
pp. F561-F570 ◽  
Author(s):  
Yanzhang Li ◽  
Xiaopeng Tong ◽  
Hasiyeti Maimaitiyiming ◽  
Kate Clemons ◽  
Ji-Min Cao ◽  
...  

cGMP-dependent protein kinase (PKG) is a multifunctional protein. Whether PKG plays a role in ischemia-reperfusion-induced kidney injury (IRI) is unknown. In this study, using an in vivo mouse model of renal IRI, we determined the effect of renal IRI on kidney PKG-I levels and also evaluated whether overexpression of PKG-I attenuates renal IRI. Our studies demonstrated that PKG-I levels (mRNA and protein) were significantly decreased in the kidney from mice undergoing renal IRI. Moreover, PKG-I transgenic mice had less renal IRI, showing improved renal function and less tubular damage compared with their wild-type littermates. Transgenic mice in the renal IRI group had decreased tubular cell apoptosis accompanied by decreased caspase 3 levels/activity and increased Bcl-2 and Bag-1 levels. In addition, transgenic mice undergoing renal IRI demonstrated reduced macrophage infiltration into the kidney and reduced production of inflammatory cytokines. In vitro studies showed that peritoneal macrophages isolated from transgenic mice had decreased migration compared with control macrophages. Taken together, these results suggest that PKG-I protects against renal IRI, at least in part through inhibiting inflammatory cell infiltration into the kidney, reducing kidney inflammation, and inhibiting tubular cell apoptosis.

2013 ◽  
Vol 305 (6) ◽  
pp. F881-F890 ◽  
Author(s):  
Hasiyeti Maimaitiyiming ◽  
Yanzhang Li ◽  
Wenpeng Cui ◽  
Xiaopeng Tong ◽  
Heather Norman ◽  
...  

Cisplatin is widely used to treat malignancies. However, its major limitation is the development of dose-dependent nephrotoxicity. The precise mechanisms of cisplatin-induced kidney damage remain unclear, and the renoprotective agents during cisplatin treatment are still lacking. Here, we demonstrated that the expression and activity of cGMP-dependent protein kinase-I (PKG-I) were reduced in cisplatin-treated renal tubular cells in vitro as well as in the kidney tissues from cisplatin-treated mice in vivo. Increasing PKG activity by both pharmacological and genetic approaches attenuated cisplatin-induced kidney cell apoptosis in vitro. This was accompanied by decreased Bax/Bcl2 ratio, caspase 3 activity, and cytochrome c release. Cisplatin-induced mitochondria membrane potential loss in the tubular cells was also prevented by increased PKG activity. All of these data suggest a protective effect of PKG on mitochondria function in renal tubular cells. Importantly, increasing PKG activity pharmacologically or genetically diminished cisplatin-induced tubular damage and preserved renal function during cisplatin treatment in vivo. Mitochondria structural and functional damage in the kidney from cisplatin-treated mice was inhibited by increased PKG activity. In addition, increasing PKG activity enhanced ciaplatin-induced cell death in several cancer cell lines. Taken together, these results suggest that increasing PKG activity may be a novel option for renoprotection during cisplatin-based chemotherapy.


2018 ◽  
Vol 238 (3) ◽  
pp. 203-219 ◽  
Author(s):  
Ghania Ramdani ◽  
Nadine Schall ◽  
Hema Kalyanaraman ◽  
Nisreen Wahwah ◽  
Sahar Moheize ◽  
...  

NO/cGMP signaling is important for bone remodeling in response to mechanical and hormonal stimuli, but the downstream mediator(s) regulating skeletal homeostasis are incompletely defined. We generated transgenic mice expressing a partly-activated, mutant cGMP-dependent protein kinase type 2 (PKG2R242Q) under control of the osteoblast-specific Col1a1 promoter to characterize the role of PKG2 in post-natal bone formation. Primary osteoblasts from these mice showed a two- to three-fold increase in basal and total PKG2 activity; they proliferated faster and were resistant to apoptosis compared to cells from WT mice. Male Col1a1-Prkg2 R242Q transgenic mice had increased osteoblast numbers, bone formation rates and Wnt/β-catenin-related gene expression in bone and a higher trabecular bone mass compared to their WT littermates. Streptozotocin-induced type 1 diabetes suppressed bone formation and caused rapid bone loss in WT mice, but male transgenic mice were protected from these effects. Surprisingly, we found no significant difference in bone micro-architecture or Wnt/β-catenin-related gene expression between female WT and transgenic mice; female mice of both genotypes showed higher systemic and osteoblastic NO/cGMP generation compared to their male counterparts, and a higher level of endogenous PKG2 activity may be responsible for masking effects of the PKG2R242Q transgene in females. Our data support sexual dimorphism in Wnt/β-catenin signaling and PKG2 regulation of this crucial pathway in bone homeostasis. This work establishes PKG2 as a key regulator of osteoblast proliferation and post-natal bone formation.


Hypertension ◽  
1996 ◽  
Vol 27 (3) ◽  
pp. 552-557 ◽  
Author(s):  
Naohisa Tamura ◽  
Hiroshi Itoh ◽  
Yoshihiro Ogawa ◽  
Osamu Nakagawa ◽  
Masaki Harada ◽  
...  

2021 ◽  
Vol 16 (1) ◽  
pp. 537-543
Author(s):  
Mei Zhang ◽  
Jing Yuan ◽  
Rong Dong ◽  
Jingjing Da ◽  
Qian Li ◽  
...  

Abstract Background Hyperhomocysteinemia (HHcy) plays an important role in the progression of many kidney diseases; however, the relationship between HHcy and ischemia-reperfusion injury (IRI)-induced acute kidney injury (IRI-induced AKI) is far from clear. In this study, we try to investigate the effect and possible mechanisms of HHcy on IRI-induced AKI. Methods Twenty C57/BL6 mice were reared with a regular diet or high methionine diet for 2 weeks (to generate HHcy mice); after that, mice were subgrouped to receive sham operation or ischemia-reperfusion surgery. Twenty four hour after reperfusion, serum creatinine, blood urea nitrogen, and Malondialdehyde (MDA) were measured. H&E staining for tubular injury, western blot for γH2AX, JNK, p-JNK, and cleaved caspase 3, and TUNEL assay for tubular cell apoptosis were also performed. Results Our results showed that HHcy did not influence the renal function and histological structure, as well as the levels of MDA, γH2AX, JNK, p-JNK, and tubular cell apoptosis in control mice. However, in IRI-induced AKI mice, HHcy caused severer renal dysfunction and tubular injury, higher levels of oxidative stress, DNA damage, JNK pathway activation, and tubular cell apoptosis. Conclusion Our results demonstrated that HHcy could exacerbate IRI-induced AKI, which may be achieved through promoting oxidative stress, DNA damage, JNK pathway activation, and consequent apoptosis.


2020 ◽  
Vol 22 (1) ◽  
pp. 52
Author(s):  
Mirja Koch ◽  
Constanze Scheel ◽  
Hongwei Ma ◽  
Fan Yang ◽  
Michael Stadlmeier ◽  
...  

Mutations in the CNGA3 gene, which encodes the A subunit of the cyclic guanosine monophosphate (cGMP)-gated cation channel in cone photoreceptor outer segments, cause total colour blindness, also referred to as achromatopsia. Cones lacking this channel protein are non-functional, accumulate high levels of the second messenger cGMP and degenerate over time after induction of ER stress. The cell death mechanisms that lead to loss of affected cones are only partially understood. Here, we explored the disease mechanisms in the Cnga3 knockout (KO) mouse model of achromatopsia. We found that another important effector of cGMP, the cGMP-dependent protein kinase 2 (Prkg2) is crucially involved in cGMP cytotoxicity of cones in Cnga3 KO mice. Virus-mediated knockdown or genetic ablation of Prkg2 in Cnga3 KO mice counteracted degeneration and preserved the number of cones. Analysis of markers of endoplasmic reticulum stress and unfolded protein response confirmed that induction of these processes in Cnga3 KO cones also depends on Prkg2. In conclusion, we identified Prkg2 as a novel key mediator of cone photoreceptor degeneration in achromatopsia. Our data suggest that this cGMP mediator could be a novel pharmacological target for future neuroprotective therapies.


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