Upregulation of PKD1L2 provokes a complex neuromuscular disease in the mouse

Following a screen for neuromuscular mouse mutants, we identified ostes, a novel N-ethyl N-nitrosourea-induced mouse mutant with muscle atrophy. Genetic and biochemical evidence shows that upregulation of the novel, uncharacterized transient receptor potential polycystic (TRPP) channel PKD1L2 (polycystic kidney disease gene 1-like 2) underlies this disease. Ostes mice suffer from chronic neuromuscular impairments including neuromuscular junction degeneration, polyneuronal innervation and myopathy. Ectopic expression of PKD1L2 in transgenic mice reproduced the ostes myopathic changes and, indeed, caused severe muscle atrophy in Tg(Pkd1l2)/Tg(Pkd1l2) mice. Moreover, double-heterozygous mice (ostes/+, Tg(Pkd1l2)/0) suffer from myopathic changes more profound than each heterozygote, indicating positive correlation between PKD1L2 levels and disease severity. We show that, in vivo, PKD1L2 primarily associates with endogenous fatty acid synthase in normal skeletal muscle, and these proteins co-localize to costameric regions of the muscle fibre. In diseased ostes/ostes muscle, both proteins are upregulated, and ostes/ostes mice show signs of abnormal lipid metabolism. This work shows the first role for a TRPP channel in neuromuscular integrity and disease

2006 UNDERLYING PURINERGIC SIGNALING IMPORTANT FOR MONOCILIUM- DEPENDENT SIGNALING IN DUCTAL EPITHELIA: IMPLICATIONS FOR

This thesis concerns purinergic signaling in renal epithelial cells of normal and polycystic kidneys. The first section discusses first principles of “purinergic signaling ” as they relate to the nephron and the urinary bladder. Remodeled and encapsulated cysts in autosomal dominant PKD (ADPKD) and remodeled “pseudocysts ” in autosomal recessive polycystic kidney disease (ARPKD) of the renal collecting duct create an ideal microenvironment for purinergic signaling. Once “trapped ” in these microenvironments in a “closed system, ” purinergic signaling becomes chronic and plays a significant epigenetic and detrimental role in the progression of ADPKD in particular, once the remodeling of the renal tissue has begun. In the PKD “cystic ” microenvironments, we argue that normal purinergic signaling within the lumen of the nephron provides detrimental acceleration of ADPKD once remodeling is complete. The second section presents data that suggest apical monocilia are sensory organelles. Renal epithelial cells release ATP constitutively under basal conditions and release higher quantities of the purine nucleotide in response to different stimuli. I

Associations of albuminuria in patients with chronic heart failure: findings in the ALiskiren Observation of heart Failure Treatment study

Aims To examine the relationships between baseline characteristics and urinary albumin excretion in the extensively phenotyped patients in the ALiskiren Observation of heart Failure Treatment (ALOFT) study.Methods and results Urinary albumin creatinine ratio (UACR) was available in 190 of 302 (63%) patients randomized in ALOFT. Of these, 107 (56%) had normal albumin excretion, 63 (33%) microalbuminuria, and 20 (11%) macroalbuminuria. Compared with patients with normoalbuminuria, those with microalbuminuria had a greater prevalence of diabetes (48 vs. 26%, P = 0.005) and a lower estimated glomerular filtration rate (eGFR) (60.7 vs. 68.3 mL/min/1.73 m2, P = 0.01). Patients with macroalbuminuria had additional differences from those with a normal UACR, including younger age (63 vs. 69 years, P = 0.02), higher glycated haemoglobin (HbA1c; 7.9 vs. 6.2%, P < 0.001), and different echocardiographic findings. Of the non-diabetic patients, 28% had microalbuminuria and 7% had macroalbuminuria. Independent predictors of UACR in these patients included N-terminal pro B-type natriuretic peptide (NT-proBNP), HbA1c, and left ventricular diastolic dimension. Increased UACR was not associated with markers of inflammation or of renin angiotensin aldosterone system activation and was not reduced by aliskiren.Conclusions Increased UACR is common in patients with heart failure, including non-diabetics. Urinary albumin creatinine ratio is independently associated with HbA1c and NT-proBNP, even in non-diabetic patients

Premature Atherosclerosis Is Associated With Hypovitaminosis D and Angiotensin-Converting Enzyme Inhibitor Non-use in Lupus Patients

Our ultimate goal is to identify and target modifiable risk factors that will reduce major cardiovascular events in African-American lupus patients. As a first step toward achieving this goal, this study was designed to explore risk factor models of preclinical atherosclerosis in a predominantly African-American group of SLE patients using variables historically associated with endothelial function in non-lupus populations. 51 subjects with SLE but without a history of clinical cardiovascular events were enrolled. At entry, a Framingham risk factor history and medication list were recorded. Sera and plasma samples were analyzed for lipids, lupus activity markers, and total 25-hydroxyvitamin D (25(OH)D) levels. Carotid ultrasound measurements were performed to determine total plaque area (TPA) in both carotids. Cases had TPA values above age-matched controls from a vascular prevention clinic population. Logistic regression and machine learning analyses were performed to create predictive models. 25(OH)D levels were significantly lower and SLE disease duration was significantly higher in cases. 25(OH)D levels inversely correlated with age-adjusted TPA. ACE-inhibitor non-use associated with case status. Logistic regression models containing ACE-inhibitor use, 25(OH)D levels, and LDL levels had a diagnostic accuracy of 84% for predicting accelerated atherosclerosis. Similar results were obtained with machine learning models, but hydroxychloroquine use associated with controls in these models. This is the first study to demonstrate an association between atherosclerotic burden and 25(OH)D insufficiency or ACE-inhibitor non-use in lupus patients. These findings provide strong rationale for the study of ACE-inhibitors and vitamin D replenishment as preventive therapies in this high-risk population