Disruption of the Plasmodium falciparum Life Cycle through Transcriptional Reprogramming by Inhibitors of Jumonji Demethylases.

Little is known about the role of the three Jumonji C (JmjC) enzymes in Plasmodium falciparum (Pf). Here, we show that JIB-04 and other established inhibitors of mammalian JmjC histone demethylases kill asexual blood stage parasites and are even more potent at blocking gametocyte development and gamete formation. In late stage parasites, JIB-04 increased levels of trimethylated lysine residues on histones, suggesting the inhibition of P. falciparum Jumonji demethylase activity. These epigenetic defects coincide with deregulation of invasion, cell motor, and sexual development gene programs, including gene targets coregulated by the PfAP2-I transcription factor and chromatin-binding factor, PfBDP1. Mechanistically, we demonstrate that PfJmj3 converts 2-oxoglutarate to succinate in an iron-dependent manner consistent with mammalian Jumonji enzymes, and this catalytic activity is inhibited by JIB-04 and other Jumonji inhibitors. Our pharmacological studies of Jumonji activity in the malaria parasite provide evidence that inhibition of these enzymatic activities is detrimental to the parasite.

Large-scale identification of human cerebrovascular proteins: Inter-tissue and intracerebral vascular protein diversity.

The human cerebrovascular system is responsible for regulating demand-dependent perfusion and maintaining the blood-brain barrier (BBB). In addition, defects in the human cerebrovasculature lead to stroke, intracerebral hemorrhage, vascular malformations, and vascular cognitive impairment. The objective of this study was to discover new proteins of the human cerebrovascular system using expression data from the Human Protein Atlas, a large-scale project which allows public access to immunohistochemical analysis of human tissues. We screened 20,158 proteins in the HPA and identified 346 expression patterns correlating to blood vessels in human brain. Independent experiments showed that 51/52 of these distributions could be experimentally replicated across different brain samples. Some proteins (40%) demonstrated endothelial cell (EC)-enriched expression, while others were expressed primarily in vascular smooth muscle cells (VSMC; 18%); 39% of these proteins were expressed in both cell types. Most brain EC markers were tissue oligospecific; that is, they were expressed in endothelia in an average of 4.8 out of 9 organs examined. Although most markers expressed in endothelial cells of the brain were present in all cerebral capillaries, a significant number (21%) were expressed only in a fraction of brain capillaries within each brain sample. Among proteins found in cerebral VSMC, virtually all were also expressed in peripheral VSMC and in non-vascular smooth muscle cells (SMC). Only one was potentially brain specific: VHL (Von Hippel-Lindau tumor suppressor). HRC (histidine rich calcium binding protein) and VHL were restricted to VSMC and not found in non-vascular tissues such as uterus or gut. In conclusion, we define a set of brain vascular proteins that could be relevant to understanding the unique physiology and pathophysiology of the human cerebrovasculature. This set of proteins defines inter-organ molecular differences in the vasculature and confirms the broad heterogeneity of vascular cells within the brain.

Risk factors of hyperparathyroidism in advanced stages of chronic kidney disease.

The pathogenesis of renal osteodystrophy is not clearly defined. We evaluate in this study the potential effect of demographic and biochemical markers on parathormone (PTH) level in patients with chronic kidney disease (CKD) stages 4 and 5. We retrospectively studied 138 patients with CKD stages 4 and 5 selected from the database of the Sheffield Kidney Institute in the interval from 1996 to 2005. All patients had baseline as well as follow-up levels of PTH, adjusted serum calcium, phosphate, calcium phosphorus product, albumin, bicarbonate and estimated glomerular filtration rate (eGFR). At baseline, serum albumin, eGFR and adjusted serum calcium levels significantly negatively correlated with PTH serum levels. Adjusted serum calcium levels at last follow-up remained a significant negative predictor of PTH levels; however, baseline PTH levels demonstrated a significant positive correlation with final serum PTH levels. This study high lights the significance of serum PTH levels at presentation on the long-term effect of parathyroid gland function. This reinforces the need for early intervention to achieve optimal control of hyperparathyroidism in CKD patients.

Conservatively managed patients with stage 5 chronic kidney disease--outcomes from a single center experience.

BACKGROUND: Limited survival data are available on chronic kidney disease stage 5 (CKD 5) patients who opt for conservative management rather than dialysis. AIM: To measure survival in such patients and investigate potential factors predicting survival. DESIGN: Retrospective survival analysis of a cohort of conservatively managed CKD 5 patients from a single center. METHODS: Survival was measured in 69 conservatively managed patients from the time they were first known to have CKD 5. Comorbidities, residual renal function and other laboratory parameters (calcium, phosphate, parathyroid hormone, albumin and hemoglobin) and blood pressure were recorded. RESULTS: Overall median patient survival from the time of first known CKD 5 was 21 months. Patients known to a nephrologist before reaching CKD 5 survived longer (median 32 months) than those presenting with CKD 5 (15 months, P = 0.025). Serum albumin >35 g/l was associated with greater survival, but other biochemical parameters, comorbidity grade and age did not predict survival. CONCLUSION: These survival data provide useful information for nephrologists counseling CKD 5 patients considering whether to pursue dialysis or conservative management. Risk factors that correlate with survival in the dialysis population may not predict survival in conservatively managed CKD 5 patients.

De novo membranous nephropathy associated with donor-specific alloantibody.

Recent evidence suggests that alloantibody may play an aetiological role in the pathogenesis of membranous glomerulopathy in native kidneys. There is an increased awareness of the significance of alloantibody on renal transplant outcome, particularly with the development of more sensitive assays. We describe a kidney transplant patient who developed de novo membranous glomerulopathy (DNMG) with heavy proteinuria in the context of a donor-specific alloantibody (DSA) directed against HLA DQ7. Proteinuria resolved and kidney function stabilized following treatment with mycophenolate mofetil and an angiotensin receptor blocker. The titre of the DSA fell in parallel with resolution of the proteinuria. This is the first reported case of DNMG after kidney transplantation clearly associated with a DSA. We hypothesize that de novo membranous glomerulopathy may be an atypical manifestation of acute antibody-mediated damage. Cases of DNMG should be screened for alloantibody and the presence of alloantibody may influence the choice of therapy.

Stem cell factor in a rat model of serum nephrotoxic nephritis.

BACKGROUND: Stem cell factor (SCF) has been implicated in many disease processes characterized by tissue remodelling and fibrosis. The growth factor (SCF) was evaluated in a rat model of nephrotoxic serum nephritis (NTN), characterized by early inflammation followed by later tissue fibrosis. METHODS: NTN was induced in male Wistar Kyoto rats using rabbit anti-rat glomerular basement membrane antibodies. Animals were sacrificed at days 7, 15, 30 and 45 (n = 4-10 per group). Rats' kidneys were immunostained for ED1 as marker of inflammation, CD34, SCF, c-kit, mast cell tryptase and markers of fibrosis; collagens III and IV and alpha-SMA. Changes in SCF protein and mRNA content were evaluated by Western blotting and Northern blotting, respectively. RESULTS: In the NTN kidney, levels of immunoreactive SCF and SCF receptor (c-kit) were significantly higher in glomerular, tubular and interstitial compartments. Mast cells were barely detectable in NTN and control rat sections. Double immunostaining showed the co-localization of SCF with alpha-SMA and of the SCF receptor with CD34 and ED1 positive cells. Immunostainable SCF protein in each of the 3 compartments, glomerular, tubular and interstitial, showed a positive linear correlation with serum creatinine, proteinuria, glomerulosclerosis score and interstitial fibrosis scores. Using multivariate analysis, immunostainable tubular SCF was a predictor of glomerular sclerosis and immunostainable glomerular SCF predicted tubular atrophy. Increased SCF immunostain was not a consequence of altered transcription as there was a fall in SCF mRNA determined by Northern blotting. Western blotting of NTN kidney homogenates revealed two bands for SCF, a 43-kDa band which decreased, and a 19-kDa band which increased throughout the study. CONCLUSION: These results highlight the potential role of SCF and its receptor in the remodelling process of the NTN kidney. Upregulation of SCF may involve a translational mechanism, with the soluble SCF protein KL-S1 (19 kDa) being derived from the transmembrane SCF protein KL-1 (43 kD) by proteolytic cleavage. The immunohistochemical staining of few CD34+ cells in NTN kidneys warrants further evaluation of the nature of these cells in the context of the inflammatory as well as the fibrotic processes.

The management of CKD: a look into the future.

The increasing global prevalence of chronic kidney disease (CKD) and end-stage renal disease with the associated spiraling cost has profound public health and economic implications. This has made slowing the progression of CKD, a major health-care priority. CKD is invariably characterized by progressive kidney fibrosis and at present, treatment aiming to slow the progression of CKD is limited to aggressive blood pressure control, with few therapies targeting the fibrotic process itself. In this review, we explore the potential of experimental therapeutic strategies, based on preventing or reversing the pathophysiologic steps of kidney remodeling that lead to fibrosis.

Impact of cardiac transplantation on kidney function: a single- center experience.

Long-term follow-up of cardiac transplant recipients reveals a progressive decline in kidney function in a significant number of patients. This complication is one of the most important prognostic parameters for the outcome of cardiac transplantation. The risk factors implicated in the pathogenesis of renal dysfunction following cardiac transplantation are numerous, with the immunosuppressive drug cyclosporine (CsA) playing a major role. This case-control study was designed to evaluate the role of different risk factors among patients who had been transplanted at the Northern General Hospital Cardiothoracic Centre (CTC) with the possibility of identifying modifiable risk factors that mitigate the nephrotoxicity of CsA. Over a 10-year period, heart transplantation was performed in 205 patients at the CTC. Seventeen patients who experienced chronic renal failure (CRF) and were treated at the outpatient clinic of the Sheffield Kidney Institute were randomly selected from those who had >2-year graft survival and follow-up after cardiac transplantation. As controls, 15 cardiac transplant patients were randomly selected from 32 with comparable survival and follow-up after transplantation and without evidence of significant renal dysfunction (serum creatinine

A targeted deletion in alpha-tectorin reveals that the tectorial membrane is required for the gain and timing of cochlear feedback.

alpha-tectorin is an extracellular matrix molecule of the inner ear. Mice homozygous for a targeted deletion in a-tectorin have tectorial membranes that are detached from the cochlear epithelium and lack all noncollagenous matrix, but the architecture of the organ of Corti is otherwise normal. The basilar membranes of wild-type and alpha-tectorin mutant mice are tuned, but the alpha-tectorin mutants are 35 dB less sensitive. Basilar membrane responses of wild-type mice exhibit a second resonance, indicating that the tectorial membrane provides an inertial mass against which outer hair cells can exert forces. Cochlear microphonics recorded in alpha-tectorin mutants differ in both phase and symmetry relative to those of wild-type mice. Thus, the tectorial membrane ensures that outer hair cells can effectively respond to basilar membrane motion and that feedback is delivered with the appropriate gain and timing required for amplification.

Oxidative stress in the context of acute cerebrovascular stroke.

BACKGROUND AND PURPOSE: Free radical generation and consequent oxidative stress in thrombotic cerebrovascular stroke have a distinctive role in the pathogenesis of ischemic brain injury. One of the potential injurious effects of homocyst(e)ine in occlusive vascular diseases is free radical generation. In the current study, we investigated the status of oxidant stress in the acute phase of thrombotic cerebrovascular stroke and the possible role of homocyst(e)ine. METHODS: We determined levels of plasma homocyst(e)ine, lipid peroxide, ascorbic acid, superoxide dismutase, and nitric oxide in 30 patients with thrombotic cerebrovascular stroke within 2 days of the onset of the attack as well as in 22 healthy volunteers of comparable age and gender. RESULTS: Statistically significant elevation of homocyst(e)ine (P<0. 001), lipid peroxide (P<0.001), and nitric oxide (P<0.001) plasma levels were observed in stroke patients compared with healthy controls. On the other hand, the antioxidant ascorbic acid plasma levels were significantly lower in the patient group compared with healthy control subjects (P<0.001). Meanwhile, superoxide dismutase plasma levels were not statistically different in either groups. The study also revealed a significant and strong positive correlation between homocyst(e)ine and lipid peroxide (r=0.85, P<0.001). Ascorbic acid plasma levels were significantly negatively correlated with both homocyst(e)ine (r=-0.875, P<0.001) and lipid peroxide (r=-0.576, P<0.001). The nitric oxide level was positively correlated with superoxide dismutase (r=0.396, P<0.05). CONCLUSIONS: We conclude that hyperhomocyst(e)inemia is a possible causal factor in free radical generation during the acute phase of thrombotic cerebrovascular stroke. Pharmacological intervention could potentially be beneficial in this setting and warrants further evaluation.