Climate Change and Sea Ice: Local Observations from the Canadian Western Arctic

Can local observations and indigenous knowledge be used to provide information that complements research on climate change? Using participatory research methodology and semi-directed interviews, we explored local and traditional knowledge about changes in sea ice in the area of Sachs Harbour, Northwest Territories. In this small Inuvialuit community, we interviewed all of the 16 community members and elders considered to be local experts on sea ice to ask about their observations. We organized their comments under the headings multiyear ice, first-year ice, fractures and pressure ridges, breakup and freeze-up seasons, and other climate-related variables that influence sea ice (such as changes in winter, spring and summer temperatures, wind, rain, and thunderstorms). Observations were remarkably consistent in providing evidence of local change in such variables as multiyear ice distribution, first-year ice thickness, and ice breakup dates. The changes observed in the 1990s were said to be without precedent and outside the normal range of variation. In assessing the relevance of Inuvialuit knowledge to scientific research on climate change, we note some of the areas in which sharing of information between the two systems of knowledge may be mutually beneficial. These include the analysis of options for adapting to climate change and the generation of research questions and hypotheses for future studies.Est-ce que les observations locales et le savoir des Autochtones peuvent aider à fournir de l'information complétant la recherche sur le changement climatique? En faisant appel à une méthodologie de recherche participative et des entrevues semi-dirigées, on a examiné le savoir local et traditionnel concernant les changements de la banquise dans la région de Sachs Harbour (Territoires du Nord-Ouest). Dans cette petite communauté inuvialuite, on a interviewé les 16 membres et aînés de la communauté considérés comme des experts locaux de la banquise pour les interroger sur leurs observations. On a organisé leurs commentaires sous les rubriques suivantes: glace pluriannuelle, glace de l'année, crêtes de fractures et de pression, saisons de débâcle et d'engel, ainsi que d'autres variables reliées au climat qui influencent la banquise (comme les changements dans les températures hivernale, printanière et estivale, le vent, la pluie et les orages). Il y avait une concordance frappante dans les observations quant aux preuves de changements à l'échelle locale dans des variables comme la distribution de la glace pluriannuelle, l'épaisseur de la glace de l'année et les dates de la débâcle. Les changements observés au cours des années 1990 étaient, selon les Autochtones, sans précédent et ils dépassaient la gamme normale des variations. En évaluant la pertinence du savoir des Inuvialuits pour la recherche scientifique sur le changement climatique, on souligne certains des domaines dans lesquels le partage de l'information entre les deux systèmes de savoir pourrait être mutuellement profitable. Ces domaines comprennent l'analyse des options visant l'adaptation au changement climatique et la formulation de questions et hypothèses de recherche pour des études ultérieures

Zoledronic acid blocks overactive Kir6.1/SUR2-dependent KATP channels in skeletal muscle and osteoblasts in a murine model of Cantú syndrome

Cantú syndrome (CS) is caused by the gain of function mutations in th

Consequences of SUR2[A478V] mutation in skeletal muscle of murine model of Cantu syndrome

(1) Background: Cantu syndrome (CS) arises from gain-of-function (GOF) mutations in th

Consequences of SUR2[A478V] mutation in skeletal muscle of murine model of Cantu syndrome

(1) Background: Cantu syndrome (CS) arises from gain-of-function (GOF) mutations in th

Glibenclamide reverses cardiovascular abnormalities of Cantu syndrome driven by KATP channel overactivity

Cantu syndrome (CS) is a complex disorder caused by gain-of-function (GoF) mutations in ABCC9 and KCNJ8, which encode the SUR2 and Kir6.1 subunits, respectively, of vascular smooth muscle (VSM) KATP channels. CS includes dilated vasculature, marked cardiac hypertrophy, and other cardiovascular abnormalities. There is currently no targeted therapy, and it is unknown whether cardiovascular features can be reversed once manifest. Using combined transgenic and pharmacological approaches in a knockin mouse model of CS, we have shown that reversal of vascular and cardiac phenotypes can be achieved by genetic downregulation of KATP channel activity specifically in VSM, and by chronic administration of the clinically used KATP channel inhibitor, glibenclamide. These findings demonstrate that VSM KATP channel GoF underlies CS cardiac enlargement and that CS-associated abnormalities are reversible, and provide evidence of in vivo efficacy of glibenclamide as a therapeutic agent in CS

Cardiovascular consequences of KATP overactivity in Cantu syndrome

Cantu syndrome (CS) is characterized by multiple vascular and cardiac abnormalities including vascular dilation and tortuosity, systemic hypotension, and cardiomegaly. The disorder is caused by gain-of-function (GOF) mutations in genes encoding pore-forming (Kir6.1, KCNJ8) and accessory (SUR2, ABCC9) ATP-sensitive potassium (KATP) channel subunits. However, there is little understanding of the link between molecular dysfunction and the complex pathophysiology observed, and there is no known treatment, in large part due to the lack of appropriate preclinical disease models in which to test therapies. Notably, expression of Kir6.1 and SUR2 does not fully overlap, and the relative contribution of KATP GOF in various cardiovascular tissues remains to be elucidated. To investigate pathophysiologic mechanisms in CS we have used CRISPR/Cas9 engineering to introduce CS-associated SUR2[A478V] and Kir6.1[V65M] mutations to the equivalent endogenous loci in mice. Mirroring human CS, both of these animals exhibit low systemic blood pressure and dilated, compliant blood vessels, as well dramatic cardiac enlargement, the effects being more severe in V65M animals than in A478V animals. In both animals, whole-cell patch-clamp recordings reveal enhanced basal KATP conductance in vascular smooth muscle, explaining vasodilation and lower blood pressure, and demonstrating a cardinal role for smooth muscle KATP dysfunction in CS etiology. Echocardiography confirms in situ cardiac enlargement and increased cardiac output in both animals. Patch-clamp recordings reveal reduced ATP sensitivity of ventricular myocyte KATP channels in A478V, but normal ATP sensitivity in V65M, suggesting that cardiac remodeling occurs secondary to KATP overactivity outside of the heart. These SUR2[A478V] and Kir6.1[V65M] animals thus reiterate the key cardiovascular features seen in human CS. They establish the molecular basis of the pathophysiological consequences of reduced smooth muscle excitability resulting from SUR2/Kir6.1-dependent KATP GOF, and provide a validated animal model in which to examine potential therapeutic approaches to treating CS

Hypotension due to Kir6.1 gain‐of‐function in vascular smooth muscle

BACKGROUND: K(ATP) channels, assembled from pore‐forming (Kir6.1 or Kir6.2) and regulatory (SUR1 or SUR2) subunits, link metabolism to excitability. Loss of Kir6.2 results in hypoglycemia and hyperinsulinemia, whereas loss of Kir6.1 causes Prinzmetal angina–like symptoms in mice. Conversely, overactivity of Kir6.2 induces neonatal diabetes in mice and humans, but consequences of Kir6.1 overactivity are unknown. METHODS AND RESULTS: We generated transgenic mice expressing wild‐type (WT), ATP‐insensitive Kir6.1 [Gly343Asp] (GD), and ATP‐insensitive Kir6.1 [Gly343Asp,Gln53Arg] (GD‐QR) subunits, under Cre‐recombinase control. Expression was induced in smooth muscle cells by crossing with smooth muscle myosin heavy chain promoter–driven tamoxifen‐inducible Cre‐recombinase (SMMHC‐Cre‐ER) mice. Three weeks after tamoxifen induction, we assessed blood pressure in anesthetized and conscious animals, as well as contractility of mesenteric artery smooth muscle and K(ATP) currents in isolated mesenteric artery myocytes. Both systolic and diastolic blood pressures were significantly reduced in GD and GD‐QR mice but normal in mice expressing the WT transgene and elevated in Kir6.1 knockout mice as well as in mice expressing dominant‐negative Kir6.1 [AAA] in smooth muscle. Contractile response of isolated GD‐QR mesenteric arteries was blunted relative to WT controls, but nitroprusside relaxation was unaffected. Basal K(ATP) conductance and pinacidil‐activated conductance were elevated in GD but not in WT myocytes. CONCLUSIONS: K(ATP) overactivity in vascular muscle can lead directly to reduced vascular contractility and lower blood pressure. We predict that gain of vascular K(ATP) function in humans would lead to a chronic vasodilatory phenotype, as indeed has recently been demonstrated in Cantu syndrome

Complex consequences of Cantu syndrome SUR2 variant R1154Q in genetically modified mice

Cantu syndrome (CS) is caused by gain-of-function (GOF) mutations in pore-forming (Kir6.1, KCNJ8) and accessory (SUR2, ABCC9) ATP-sensitive potassium (KATP) channel subunits, the most common mutations being SUR2[R1154Q] and SUR2[R1154W], carried by approximately 30% of patients. We used CRISPR/Cas9 genome engineering to introduce the equivalent of the human SUR2[R1154Q] mutation into the mouse ABCC9 gene. Along with minimal CS disease features, R1154Q cardiomyocytes and vascular smooth muscle showed much lower KATP current density and pinacidil activation than WT cells. Almost complete loss of SUR2-dependent protein and KATP in homozygous R1154Q ventricles revealed underlying diazoxide-sensitive SUR1-dependent KATP channel activity. Surprisingly, sequencing of SUR2 cDNA revealed 2 distinct transcripts, one encoding full-length SUR2 protein; and the other with an in-frame deletion of 93 bases (corresponding to 31 amino acids encoded by exon 28) that was present in approximately 40% and approximately 90% of transcripts from hetero- and homozygous R1154Q tissues, respectively. Recombinant expression of SUR2A protein lacking exon 28 resulted in nonfunctional channels. CS tissue from SUR2[R1154Q] mice and human induced pluripotent stem cell-derived (hiPSC-derived) cardiomyocytes showed only full-length SUR2 transcripts, although further studies will be required in order to fully test whether SUR2[R1154Q] or other CS mutations might result in aberrant splicing and variable expressivity of disease features in human CS

Challenges and Opportunities of Epidemiological Studies to Reduce the Burden of Cancers in Young Adults.

There are >1.9 million survivors of adolescent and young adult cancers (AYA, diagnosed at ages 15-39) living in the U.S. today. Epidemiologic studies to address the cancer burden in this group have been a relatively recent focus of the research community. In this article, we discuss approaches and data resources for cancer epidemiology and health services research in the AYA population. We consider research that uses data from cancer registries, vital records, healthcare utilization, and surveys, and the accompanying challenges and opportunities of each. To illustrate the strengths of each data source, we present example research questions or areas that are aligned with these data sources and salient to AYAs. Integrating the respective strengths of cancer registry, vital records, healthcare data, and survey-based studies sets the foundation for innovative and impactful research on AYA cancer treatment and survivorship to inform a comprehensive understanding of diverse AYA needs and experiences