Low-salt diet and cyclosporine nephrotoxicity: changes in kidney cell metabolism.

Cyclosporine (CsA) is a highly effective immunosuppressant used in patients after transplantation; however, its use is limited by nephrotoxicity. Salt depletion is known to enhance CsA-induced nephrotoxicity in the rat, but the underlying molecular mechanisms are not completely understood. The goal of our study was to identify the molecular effects of salt depletion alone and in combination with CsA on the kidney using a proteo-metabolomic strategy. Rats (n = 6) were assigned to four study groups: (1) normal controls, (2) low-salt fed controls, (3) 10 mg/kg/d CsA for 28 days on a normal diet, (4) 10 mg/kg/d CsA for 28 days on low-salt diet. Low-salt diet redirected kidney energy metabolism toward mitochondria as indicated by a higher energy charge than in normal-fed controls. Low-salt diet alone reduced phospho-AKT and phospho-STAT3 levels and changed the expression of ion transporters PDZK1 and CLIC1. CsA induced macro- and microvesicular tubular epithelial vacuolization and reduced energy charge, changes that were more significant in low-salt fed animals, probably because of their more pronounced dependence on mitochondria. Here, CsA increased phospho-JAK2 and phospho-STAT3 levels and reduced the phospho-IKKγ and p65 proteins, thus activating NF-κB signaling. Decreased expression of lactate transport regulator CD147 and phospho-AKT was also observed after CsA exposure in low-salt rats, indicating a decrease in glycolysis. In summary, our study suggests a key role for PDZK1, CD147, JAK/STAT, and AKT signaling in CsA-induced nephrotoxicity and proposes mechanistic explanations on why rats fed a low-salt diet have higher sensitivity to CsA.

Bezielle (BZL101)-induced oxidative stress damage followed by redistribution of metabolic fluxes in breast cancer cells: a combined proteomic and metabolomic study.

Bezielle is an orally administered aqueous extract of Scutellaria barbata for treatment of advanced and metastatic breast cancer. Phase I trials showed promising tolerability and efficacy. In our study, we used a combined proteomic-metabolomic approach to investigate the molecular pathways affected by Bezielle in ER-positive BT474 and ER-negative SKBR3 cell lines. In both, Bezielle inhibited cell proliferation, induced cell death and G2 cycle arrest by regulating the mediator proteins Jab1, p27(Kip1) and p21(Cip1) . In addition, it stimulated reactive oxygen species production, hyperactivation of PARP and inhibition of glycolysis. Bezielle's ability to induce oxidative stress was associated with the changes in expression of redox potential maintaining enzymes: glutathione- and thioredoxin-related proteins and peroxiredoxins. In regards to cell metabolism, decreased expression of α-enolase was associated with a reduction of de novo (13) C-lactate formation. Reduced Krebs cycle activity as evidenced by the reduced expression of α-ketoglutarate dehydrogenase and succinyl-CoA synthetase led to decreased intracellular succinate concentrations. By inhibiting glucose metabolism, cells reacted by lowering the expression of glucose transporters and resulting in decreased intracellular glucose concentration. Decreased expression of fatty acid synthase and reduced concentration of phosphocholine indicated considerable changes in phospholipid metabolism. Ultimately, by inhibiting the major energy-producing pathways, Bezielle caused depletion of ATP and NAD(H). Both cell lines were responsive, thus suggesting that Bezielle has the potential to be effective against ER-negative breast cancers. In conclusion, Bezielle's cytotoxicity toward cancer cells is primarily based on inhibition of metabolic pathways that are preferentially activated in tumor cells thus explaining its specificity for cancer cells.

Association of DJ-1/PTEN/AKT- and ASK1/p38-mediated cell signalling with ischaemic cardiomyopathy.

AIMS: Dilated cardiomyopathies from chronic ischaemia (ISCM) or idiopathic (IDCM) pathological mechanisms are accompanied by similar clinical symptoms but may differ in protein expression, cell metabolism, and signalling processes at the cellular level. Using a combination of proteomic and metabolomic profiling, we sought to decipher the relationships between the metabolism and cellular signalling pathways in human heart tissues collected from patients with ISCM, IDCM, and those without heart disease and dilation. METHODS AND RESULTS: The comparative analysis suggested a decrease in glycolysis, Krebs cycle, and malate-aspartate shuttle activities in both types of cardiomyopathies and an increase in ketone body oxidation only in ISCM. Chronic ischaemic injury was associated with increased DJ-1 and decreased phosphatase and tensin homolog (PTEN) protein expression. The reduced PTEN expression was accompanied by increased phosphorylation of cell-protective AKT. Phosphorylation at T845 of apoptosis signal-regulating kinase 1 and p38 mitogen-activated protein kinase proteins, with no change in the phosphorylation of extracellular signal-regulated kinases, was also observed. The downregulation of peptidyl-prolyl cis/trans isomerase and NF-κB essential modulator potentially inhibits NF-κB-initiated processes. CONCLUSION: The present study characterized differences in the molecular mechanisms, metabolism, and pathological cell signalling associated with ISCM and IDCM, which may provide novel targets for intervention at the cellular level.