Simvastatin Sodium Salt and Fluvastatin Interact with Human Gap Junction Gamma-3 Protein

Finding pleiomorphic targets for drugs allows new indications or warnings for treatment to be identified. As test of concept, we applied a new chemical genomics approach to uncover additional targets for the widely prescribed lipid-lowering pro-drug simvastatin. We used mRNA extracted from internal mammary artery from patients undergoing coronary artery surgery to prepare a viral cardiovascular protein library, using T7 bacteriophage. We then studied interactions of clones of the bacteriophage, each expressing a different cardiovascular polypeptide, with surface-bound simvastatin in 96-well plates. To maximise likelihood of identifying meaningful interactions between simvastatin and vascular peptides, we used a validated photo-immobilisation method to apply a series of different chemical linkers to bind simvastatin so as to present multiple orientations of its constituent components to potential targets. Three rounds of biopanning identified consistent interaction with the clone expressing part of the gene GJC3, which maps to Homo sapiens chromosome 7, and codes for gap junction gamma-3 protein, also known as connexin 30.2/31.3 (mouse connexin Cx29). Further analysis indicated the binding site to be for the N-terminal domain putatively ‘regulating’ connexin hemichannel and gap junction pores. Using immunohistochemistry we found connexin 30.2/31.3 to be present in samples of artery similar to those used to prepare the bacteriophage library. Surface plasmon resonance revealed that a 25 amino acid synthetic peptide representing the discovered N-terminus did not interact with simvastatin lactone, but did bind to the hydrolysed HMG CoA inhibitor, simvastatin acid. This interaction was also seen for fluvastatin. The gap junction blockers carbenoxolone and flufenamic acid also interacted with the same peptide providing insight into potential site of binding. These findings raise key questions about the functional significance of GJC3 transcripts in the vasculature and other tissues, and this connexin’s role in therapeutic and adverse effects of statins in a range of disease states

Elevated plasma Galectin-3 is associated with major adverse kidney events and death after ICU admission.

BackgroundGalectin-3 (Gal-3) is a proinflammatory and profibrotic protein especially overexpressed after Acute Kidney Injury (AKI). The early renal prognostic value of Gal-3 after AKI in critically ill patients remains unexplored. The objective was to evaluate the prognostic value of plasma level of Gal-3 for Major Adverse Kidney Events (MAKE) and mortality 30 days after ICU admission across AKI stages.MethodsThis is an ancillary study of a prospective, observational, multicenter cohort (FROG-ICU). AKI was defined using KDIGO definition.ResultsTwo thousand and seventy-six patients had a Gal-3 plasma level measurement at ICU admission. Seven hundred and twenty-three (34.8%) were females and the median age was 63 [51, 74] years. Eight hundred and seven (38.9%) patients developed MAKE, 774 (37.3%) had AKI and mortality rate at 30 days was 22.4% (N = 465). Patients who developed MAKE had higher Gal-3 level at admission compared to patients without (30.2 [20.8, 49.2] ng/ml versus 16.9 [12.7, 24.3] ng/ml, p < 0.001, respectively. The area under the receiver operating characteristic curve of Gal-3 to predict MAKE was 0.76 CI95% [0.74-0.78], p < 0.001. Gal-3 was associated with MAKE (OR 1.80 CI95% [1.68-1.93], p < 0.001, non-adjusted and OR 1.37 CI95% [1.27-1.49], p < 0.001, adjusted). The use of Gal-3 improved prediction performance of prediction model including SAPSII, Screatadm, pNGAL with a NRI of 0.27 CI95%(0.16-0.38), p < 0.001. Median Gal-3 was higher in non-survivors than in survivors at 30 days (29.2 [20.2, 49.2] ng/ml versus 18.8 [13.3, 29.2] ng/ml, p < 0.001, respectively).ConclusionPlasma levels of Gal-3 were strongly associated with renal function, with an increased risk of MAKE and death after ICU admission. Trial registration ClinicalTrials.gov NCT01367093. Registered on 6 June 2011

Genetic inactivation of Semaphorin 3C protects mice from acute kidney injury

To guide the development of therapeutic interventions for acute kidney injury, elucidating the deleterious pathways of this global health problem is highly warranted. Emerging evidence has indicated a pivotal role of endothelial dysfunction in the etiology of this disease. We found that the class III semaphorin SEMA3C was ectopically upregulated with full length protein excreted into the blood and truncated protein secreted into the urine upon kidney injury and hypothesized a role for SEAM3C in acute kidney injury. Sema3c was genetically abrogated during acute kidney injury and subsequent kidney morphological and functional defects in two well-characterized models of acute kidney injury; warm ischemia/reperfusion and folic acid injection were analyzed. Employing a beta actin-dependent, inducible knockout of Sema3c, we demonstrate that in acute kidney injury SEMA3C promotes interstitial edema, leucocyte infiltration and tubular injury. Additionally, intravital microscopy combined with Evans Blue dye extravasation and primary culture of magnetically sorted peritubular endothelial cells identified a novel role for SEMA3C in promoting vascular permeability. Thus, our study points to microvascular permeability as an important driver of injury in acute kidney injury, and to SEMA3C as a novel permeability factor and potential target for therapeutic intervention