Type 1 ryanodine receptor interactions

Excitation-contraction coupling is an essential part of skeletal muscle contraction. It encompasses the sensing of depolarisation of the plasma membrane coupled with the release of Ca2+ from intracellular stores. The channel responsible for this release is called the Ryanodine receptor (RyR), and forms a hub of interacting proteins which work in concert to regulate the release of Ca2+ through this channel. The aim of this work was to characterise possible novel interactions with a proline-rich region of the RyR1, to characterise a monoclonal antibody (mAb VF1c) raised against a junctional sarcoplasmic reticulum protein postulated to interact with RyR1, and to characterise the protein recognised by this antibody in models of skeletal muscle disease such as Duchenne Muscular dystrophy (DMD) and sarcopenia. These experiments were performed using cell culture, protein purification via immunoprecipitation, affinity purification, low pressure chromatography and western blotting techniques. It was found that the RyR1 complex isolated from rat skeletal muscle co-purifies with the Growth factor receptor bound protein 2 (GRB2), very possibly via an interaction between the proline rich region of RyR1 and one of the SH3 domains located on the GRB2 protein. It was also found that Pleiotrophin and Phospholipase Cγ1, suggested interactors of the proline rich region of RyR1, did not co-purify with the RyR1 complex. Characterisation of mAb VF1c determined that this monoclonal antibody interacts with junctophilin 1, and binds to this protein between the region of 369-460, as determined by western blotting of JPH1 fragments expressed in yeast. It was also found that JPH1 and JPH2 are differentially regulated in different muscles of rabbit, where the highest amount of both proteins was found in the extensor digitorum longus (EDL) muscle. JPH1 and 2 levels were also examined in three rodent models of disease: the mdx mouse (a model of DMD), chronic intermittent hypoxia (CIH)-treated rat, and aged and adult mice, a model of sarcopenia. In the EDL and soleus muscle of CIH treated rats, no difference in either JPH1 or JPH2 abundance was detected in either muscle. An examination of JPH1 and 2 expression in mdx and wild type controls diaphragm, vastus lateralis, soleus and gastrocnemius muscle found no major differences in JPH1 abundance, while JPH2 was decreased in mdx gastrocnemius compared to wild type. In a mouse model of sarcopenia, JPH1 abundance was found to be increased in aged soleus but not in aged quadriceps, while in exercised quadriceps, JPH2 abundance was decreased compared to unexercised controls. Taken together, these results have implications for the regulation of RyR1 and JPH1 and 2 in skeletal muscle in both physiological and pathological states, and provide a newly characterised antibody to expand the field of JPH1 research.

Régulation de la lipoprotéine lipase macrophagique dans l'hypercholestérolémie familiale et le diabète de type 2

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Rôle de la protéine virale Vpu dans le cycle de multiplication du virus de l'immunodéficience humaine de type 1 (VIH-1)

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Caractérisation du rôle de la protéine cellulaire Staufen au niveau du cycle de réplication du virus d'immunodéficience type 1

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Étude de l'immunopathogenèse de la candidose oropharyngée chez la souris transgénique exprimant le génome du virus de l'immunodéficience humaine de type 1 (VIH-1)

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Étude du mécanisme de décalage de phase de lecture en-1 du virus de l'immunodéficience humaine de type 1 et de son importance dans la réplication du virus

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Étude des mécanismes non-conventionnels de traduction chez le virus de l'immunodéficience humaine de type 1 et le virus de l'hépatite C

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Étude du rôle de la protéine Staufen1 dans le cycle de réplication du virus d'immunodéficience humaine de type 1

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Relations entre la lipolyse adipocytaire, la périlipine et l'obésité dans une perspective de physiopathologie telle le diabète de type II

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Integrase, the central DNA flap and human immunodeficiency virus type 1 nuclear import

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Remodelage électrique cardiaque chez les souris transgéniques surexprimant le récepteur de type 1 de l'angiotensine II

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Molecular and functional studies of human immunodeficiency virus type 1 accessory protein

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

The Genetic Landscape of Renal Complications in Type 1 Diabetes

Diabetes is the leading cause of end stage renal disease. Despite evidence for a substantial heritability of diabetic kidney disease, efforts to identify genetic susceptibility variants have had limited success. We extended previous efforts in three dimensions, examining a more comprehensive set of genetic variants in larger numbers of subjects with type 1 diabetes characterized for a wider range of cross-sectional diabetic kidney disease phenotypes. In 2,843 subjects, we estimated that the heritability of diabetic kidney disease was 35% ( p=6x10-3 ). Genome-wide association analysis and replication in 12,540 individuals identified no single variants reaching stringent levels of significance and, despite excellent power, provided little independent confirmation of previously published associated variants. Whole exome sequencing in 997 subjects failed to identify any large-effect coding alleles of lower frequency influencing the risk of diabetic kidney disease. However, sets of alleles increasing body mass index ( p=2.2×10-5) and the risk of type 2 diabetes (p=6.1x10-4 ) were associated with the risk of diabetic kidney disease. We also found genome-wide genetic correlation between diabetic kidney disease and failure at smoking cessation ( p=1.1×10-4 ). Pathway analysis implicated ascorbate and aldarate metabolism ( p=9×10-6), and pentose and glucuronate interconversions ( p=3×10-6) in pathogenesis of diabetic kidney disease. These data provide further evidence for the role of genetic factors influencing diabetic kidney disease in those with type 1 diabetes and highlight some key pathways that may be responsible. Altogether these results reveal important biology behind the major cause of kidney disease.  

Psychological factors associated with self-management among adolescents with Type 1 diabetes: a review

This review aims to synthesise the literature examining the psychosocial variables related to self-management (insulin adherence, non-adherence and administration, blood sugar monitoring, dietary behaviour, exercise behaviour) in adolescents with type 1 diabetes.
A systematic search of three electronic databases was carried out and, after the application of eligibility criteria, 21 articles were assessed for quality prior to data extraction. Numerous psychological factors were found to be associated with self-management; however, correlations were typically small to moderate. The strongest associations were found between social anxiety and diet (among males); greater intrinsic motivation, conscientiousness and diet; and extraversion and exercise.

Serum Fatty Acid Binding Protein 4 (FABP4) Predicts Pre-eclampsia in Women with Type 1 Diabetes

Objective: To examine the association between fatty acid binding protein 4 (FABP4) and pre-eclampsia risk in women with type 1 diabetes.
Reesearch Design and Methods: Serum FABP4 was measured in 710 women from the Diabetes and Pre-eclampsia Intervention Trial (DAPIT) in early pregnancy and in the second trimester (median 14 and 26 weeks gestation, respectively).
Results: FABP4 was significantly elevated in early pregnancy (geometric mean 15.8 ng/mL [interquartile range 11.6–21.4] vs. 12.7 ng/mL [interquartile range 9.6–17]; P < 0.001) and the second trimester (18.8 ng/mL [interquartile range 13.6–25.8] vs. 14.6 ng/mL [interquartile range 10.8–19.7]; P < 0.001) in women in whom pre-eclampsia later developed. Elevated second-trimester FABP4 level was independently associated with pre-eclampsia (odds ratio 2.87 [95% CI 1.24, 6.68], P = 0.03). The addition of FABP4 to established risk factors significantly improved net reclassification improvement at both time points and integrated discrimination improvement in the second trimester.
Conclusions: Increased second-trimester FABP4 independently predicted pre-eclampsia and significantly improved reclassification and discrimination. FABP4 shows potential as a novel biomarker for pre-eclampsia prediction in women with type 1 diabetes.