Identification of Nucleoside Analogs as Inducers of Neuronal Differentiation in a Human Reporter Cell Line and Adult Stem Cells

Nucleoside analogs (NSAs) were among the first chemotherapeutic agents and could also be useful for the manipulation of cell fate. To investigate the potential of NSAs for the induction of neuronal differentiation, we developed a novel phenotypic assay based on a human neuron‐committed teratocarcinoma cell line (NT2) as a model for neuronal progenitors and constructed a NT2‐based reporter cell line that expressed eGFP under the control of a neuron‐specific promoter. We tested 38 structurally related NSAs and determined their activity to induce neuronal differentiation by immunocytochemistry of neuronal marker proteins, live cell imaging, fluorometric detection and immunoblot analysis. We identified twelve NSAs, which induced neuronal differentiation to different extents. NSAs with highest activity carried a halogen substituent at their pyrimidine nucleobase and an unmodified or 2′‐O‐methyl substituted 2‐deoxy‐β‐D‐ribofuranosyl residue as glyconic moiety. Cladribine, a purine nucleoside with similar structural features and in use to treat leukemia and multiple sclerosis, induced also differentiation of adult human neural crest‐derived stem cells. Our results suggest that NSAs could be useful for the manipulation of neuronal cell fate in cell replacement therapy or treatment of neurodegenerative disorders. The data on the structure and function relationship will help to design compounds with increased activity and low toxicity.     

A mouse model for the renal salt-wasting syndrome pseudohypoaldosteronism

Aldosterone-dependent epithelial sodium transport in the distal nephron is mediated by the absorption of sodium through the highly selective, amiloride-sensitive epithelial sodium channel (ENaC) made of three homologous subunits (α, β, and γ). In human, autosomal recessive mutations of α, β, or γENaC subunits cause pseudohypoaldosteronism type 1 (PHA-1), a renal salt-wasting syndrome characterized by severe hypovolemia, high plasma aldosterone, hyponatremia, life-threatening hyperkaliemia, and metabolic acidosis. In the mouse, inactivation of αENaC results in failure to clear fetal lung liquid at birth and in early neonatal death, preventing the observation of a PHA-1 renal phenotype. Transgenic expression of αENaC driven by a cytomegalovirus promoter in αENaC(−/−) knockout mice [αENaC(−/−)Tg] rescued the perinatal lethal pulmonary phenotype and partially restored Na⁺ transport in renal, colonic, and pulmonary epithelia. At days 5–9, however, αENaC(−/−)Tg mice showed clinical features of severe PHA-1 with metabolic acidosis, urinary salt-wasting, growth retardation, and 50% mortality. Adult αENaC(−/−)Tg survivors exhibited a compensated PHA-1 with normal acid/base and electrolyte values but 6-fold elevation of plasma aldosterone compared with wild-type littermate controls. We conclude that partial restoration of ENaC-mediated Na⁺ absorption in this transgenic mouse results in a mouse model for PHA-1.     

Increased prevalence of familial autoimmunity in simplex and multiplex families with juvenile rheumatoid arthritis

OBJECTIVE: To determine if the prevalence of autoimmunity among relatives of patients with juvenile rheumatoid arthritis (JRA) is greater than that among relatives of healthy volunteer control subjects. METHODS: Interviews were used to obtain histories of the following disorders among living first- and second-degree relatives of 110 patients and 45 controls: alopecia areata, ankylosing spondylitis, dermatomyositis, Graves' disease, Hashimoto thyroiditis, insulin-dependent diabetes mellitus, inflammatory bowel disease, iritis, JRA, multiple sclerosis, psoriasis, RA, systemic lupus erythematosus, and vitiligo. Chi-squares, odds ratios (ORs), and 95% confidence intervals (95% CIs) were calculated. Families of 23 JRA affected sibpairs were interviewed subsequently. RESULTS: There were no significant differences between patients and controls with regard to age, sex, ethnicity, or family size. Patients had 1,228 relatives and controls had 496 relatives. Of all the relatives of the patients, 155 had at least 1 autoimmune disorder, compared with 20 relatives of the controls (12.6% versus 4.0%; OR 3.4 [95% CI 2.1-5.7], P < 0.000001). The prevalence of autoimmunity was increased in first-degree and in second-degree relatives of patients (16.1% and 10.6%, respectively). The prevalence of Hashimoto thyroiditis was significantly higher in the relatives of patients (OR 3.5 [95% CI 1.6-7.9], P = 0.0008). The prevalences of other disorders were not significantly different. JRA affected sibpair families had an increased prevalence of autoimmunity (15.0%). A history of arthritis was found significantly more frequently in the JRA affected sibpair families, but not in the simplex families. CONCLUSION: These data demonstrate that the prevalence of autoimmunity is significantly higher among first- and second-degree relatives of JRA patients. This suggests that clinically different autoimmune phenotypes may share common susceptibility genes, which may act as risk factors for autoimmunity.     

Transjugular intrahepatic portosystemic shunt (TIPS) augments hyperinsulinemia in patients with cirrhosis

BACKGROUND/AIMS: Cirrhosis of the liver is characterized by glucose intolerance and hyperinsulinemia. Both increased insulin secretion and decreased insulin clearance appear to contribute to hyperinsulinemia in cirrhotic patients. A decrease in hepatic insulin extraction rate may be due either to hepatocellular dysfunction or to portosystemic shunting with decreased first-pass insulin clearance. METHODS: To specifically address the contribution of portosystemic shunting to the pathogenesis of hyperinsulinemia in cirrhotic patients, we analyzed glycemic control and insulin levels in fasting serum in 23 cirrhotic patients before and after transjugular intrahepatic portosystemic shunt (TIPS). RESULTS: Compared to respective values in healthy controls, C-peptide, insulin and proinsulin concentrations at baseline were increased by 340%, 120% and by 100% in cirrhotic patients (all p<0.05). In cirrhotic patients insulin levels before TIPS averaged 104+/-73 pmol/l and increased by more than 50% to 163+/-118 pmol/l after TIPS (p<0.01), whereas levels of C-peptide and proinsulin showed no significant change. Glucose and fructosamin levels also remained unchanged after TIPS. CONCLUSION: Our data demonstrate that TIPS does not impair glycemic control in cirrhotic patients and that an increase in portosystemic shunting augments hyperinsulinemia, most likely by decreasing hepatic insulin clearance.     

Prevalence of gestational diabetes mellitus in urban and rural Tanzania

Aim

To estimate prevalence of gestational diabetes mellitus (GDM) and associated determinants in urban and rural Tanzania.

Methods

A cross-sectional study was conducted from 2011 through 2012 in selected urban and rural communities. Pregnant women (609 urban, 301 rural), who were not previously known to have diabetes, participated during usual ante-natal clinic visits. Capillary blood samples were collected at fasting and 2 h after 75 g glucose load and were measured using HemoCue. Diagnosis of GDM was made using 1999 World Health Organization (WHO) criteria.

Results

Women in rural areas were younger (26.6 years) than in urban areas (27.5 years). Mean gestational age, height, and mid-upper arm circumference (MUAC) were similar for the two areas. Overall prevalence of GDM averaged 5.9%, with 8.4% in urban area and 1.0% in rural area. Prevalence of GDM was higher for women who had a previous stillbirth (OR 2.8, 95% CI 1.5–5.4), family history of type 2 diabetes (OR 2.1, 95% CI 1.1–4.2), and MUAC above 28 cm (OR 1.9, 95% CI 1.1–3.3), and lower for women with normal hemoglobin compared with anemia (OR 0.45, 95% CI 0.22–0.93).

Conclusions

Prevalence of GDM is higher than expected in urban areas in Tanzania, indicating an increasing population who are at risk for delivery complications and type 2 diabetes in Sub-Saharan Africa.     

Brain angiotensin II and angiotensin IV receptors as potential Alzheimer’s disease therapeutic targets

Alzheimer’s disease (AD) is a neurodegenerative disorder that is multifactorial in nature. Yet, despite being the most common form of dementia in the elderly, AD’s primary cause remains unknown. As such, there is currently little to offer AD patients as the vast majority of recently tested therapies have either failed in well-controlled clinical trials or inadequately treat AD. Recently, emerging preclinical and clinical evidence has associated the brain renin angiotensin system (RAS) to AD pathology. Accordingly, various components of the brain RAS were shown to be altered in AD patients and mouse models, including the angiotensin II type 1 (AT1R), angiotensin IV receptor (AT4R), and Mas receptors. Collectively, the changes observed within the RAS have been proposed to contribute to many of the neuropathological hallmarks of AD, including the neuronal, cognitive, and vascular dysfunctions. Accumulating evidence has additionally identified antihypertensive medications targeting the RAS, particularly angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs), to delay AD onset and progression. In this review, we will discuss the emergence of the RAS’s involvement in AD and highlight putative mechanisms of action underlying ARB’s beneficial effects that may explain their ability to modify the risk of developing AD or AD progression. The RAS may provide novel molecular targets for recovering memory pathways, cerebrovascular function, and other pathological landmarks of AD.

     

Aerobic training in patients with anoctamin 5 myopathy and hyperckemia

Introduction: Anoctamin 5 deficiency has recently been defined to cause limb‐girdle muscular dystrophy type 2L (LGMD2L) with pronounced hyperCKemia. No treatment interventions have been made so far in this condition. Methods: In 6 patients with LGMD2L, we studied the effect of home‐based, pulse‐watch monitored, moderate‐intensity exercise on a cycle ergometer for 30 minutes, 3 times weekly, for 10 weeks. Plasma creatine kinase (CK) was assessed before, during, and after the program as a marker of muscle damage. Primary outcome measures were maximum oxygen uptake (VO_2max) and time in the 5‐repetitions‐sit‐to‐stand test (FRSTST). Results: Training resulted in improvements in VO_2max (27 ± 7%; P = 0.0001) and FRSTST time (35 ± 12%; P = 0.007). Improvements in physiologic and functional muscle testing were accompanied by stable CK levels and no reports of adverse effects. Conclusions: These findings suggest that supervised aerobic exercise training is safe and effective in improving oxidative capacity and muscle function in patients with anoctamin 5 deficiency. Muscle Nerve 50 : 119–123, 2014     

Accelerated aging of selective brain structures in human immunodeficiency virus infection: a controlled,longitudinal magnetic resonance imaging study

Advances in treatment have transformed human immunodeficiency virus (HIV) infection from an inexorable march to severe morbidity and premature death to a manageable chronic condition, often marked by good health. Thus, infected individuals are living long enough that there is a potential for interaction with normal senescence effects on various organ systems, including the brain. To examine this interaction, the brains of 51 individuals with HIV infection and 65 uninfected controls were studied using 351 magnetic resonance imaging and a battery of neuropsychological tests collected 2 or more times over follow-up periods ranging from 6 months to 8 years. Brain tissue regions of interest showed expected age-related decrease in volume; cerebrospinal fluid-filled spaces showed increase in volume for both groups. Although HIV-infected individuals were in good general health, and free of clinically-detectable dementia, several brain regions supporting higher-order cognition and integration of functions showed acceleration of the normal aging trajectory, including neocortex, which extended from the frontal and temporal poles to the parietal lobe, and the thalamus. Beyond an anticipated increase in lateral ventricle and Sylvian fissure volumes and decrease in tissue volumes (specifically, the frontal and sensorimotor neocortices, thalamus, and hippocampus) with longer duration of illness, most regions also showed accelerated disease progression. This accelerated loss of cortical tissue may represent a risk factor for premature cognitive and motor compromise if not dementia. On a more promising note, HIV-infected patients with increasing CD4 counts exhibited slower expansion of Sylvian fissure volume and slower declines of frontal and temporoparietal cortices, insula, and hippocampus tissue volumes. Thus, attenuated shrinkage of these brain regions, likely with adequate pharmacologic treatment and control of further infection, has the potential of abating decline in associated higher-order functions, notably, explicit memory, executive functions, self-regulation, and visuospatial abilities.     

Generation and characterization of potential dengue vaccine candidates based on domain III of the envelope protein and the capsid protein of the four serotypes of dengue virus

Dengue is currently one of the most important arthropod-borne diseases, causing up to 25,000 deaths annually. There is currently no vaccine to prevent dengue virus infection, which needs a tetravalent vaccine approach. In this work, we describe the cloning and expression in Escherichia coli of envelope domain III-capsid chimeric proteins (DIIIC) of the four dengue serotypes as a tetravalent dengue vaccine candidate that is potentially able to generate humoral and cellular immunity. The recombinant proteins were purified to more than 85 % purity and were recognized by anti-dengue mouse and human sera. Mass spectrometry analysis verified the identity of the proteins and the correct formation of the intracatenary disulfide bond in the domain III region. The chimeric DIIIC proteins were also serotype-specific, and in the presence of oligonucleotides, they formed aggregates that were visible by electron microscopy. These results support the future use of DIIIC recombinant chimeric proteins in preclinical studies in mice for assessing their immunogenicity and efficacy.