A5070434241- Muscle Physiology and Disorders
- Genetics and Physical Performance
- Telomeres, Telomerase, and Senescence
- Cardiovascular Effects of Exercise
- Nerve injury and regeneration
- Adipose Tissue and Metabolism
- Wound Healing and Treatments
- Tissue Engineering and Regenerative Medicine
- Exercise and Physiological Responses
- Congenital heart defects research
- Mitochondrial Function and Pathology
- Knee injuries and reconstruction techniques
- Sports Performance and Training
- Renin-Angiotensin System Studies
- Silk-based biomaterials and applications
- Pancreatic function and diabetes
- Nerve Injury and Rehabilitation
- Spaceflight effects on biology
- Mesenchymal stem cell research
- Muscle metabolism and nutrition
- Zebrafish Biomedical Research Applications
- Angiogenesis and VEGF in Cancer
- Neurogenesis and neuroplasticity mechanisms
- Nutrition and Health in Aging
- Virtual Reality Applications and Impacts
University of Prince Edward Island
2017-2022
Texas A&M University
2021-2022
Dalhousie University
2022
McMaster University
2008-2021
Mitchell Institute
2021
Hospital for Sick Children
2013-2018
SickKids Foundation
2016
Toronto Public Health
2015
International College of Applied Kinesiology-USA
2008-2010
St. Francis Xavier University
2009
The regulation of muscle stem cells in humans response to injury remains largely undefined. Recently, interleukin-6 (IL-6) has been implicated cell (satellite cell)-mediated hypertrophy animals; however, the role IL-6 satellite (SC) following muscle-lengthening contractions not studied.Eight subjects (age 22+/-1 y; 79+/-8 kg) performed 300 maximal unilateral lengthening (3.14 rad.s(-1)) knee extensors. Blood and samples were collected before at 4, 24, 72, 120 hours post intervention. IL-6,...
•Sox2 regulates murine skin repair•Sox2 the neural crest precursor response to tissue injury•Sox2 identifies a nerve terminal-associated in hair follicles Nerve-derived cells are essential for regeneration certain animals, such as newts. Here, we asked whether they play similar role during mammalian repair, focusing on Sox2-positive precursors skin. In adult skin, Sox2 was expressed nerve-terminal-associated (NCPCs) around follicle bulge, and following injury induced nerve-derived cells,...
Abstract Background Human genetic disorders and transgenic mouse models have shown that mitochondrial DNA (mtDNA) mutations telomere dysfunction instigate the aging process. Epidemiologically, exercise is associated with greater life expectancy reduced risk of chronic diseases. While beneficial effects are well established, molecular mechanisms instigating these observations remain unclear. Results Endurance reduces mtDNA mutation burden, alleviates multisystem pathology, increases lifespan...
Recent reports of directed reprogramming have raised questions about the stability cell lineages. Here, we addressed this issue, focusing upon skin-derived precursors (SKPs), a dermally derived precursor cell. We show by lineage tracing that murine SKPs from dorsal skin originate mesenchymal and not neural crest-derived cells. These mesenchymally can, without genetic manipulation, generate functional Schwann cells, crest type, are highly similar at transcriptional level to cells isolated...
Johnston, APW, Burke, DG, MacNeil, LG, and Candow, DG. Effect of creatine supplementation during cast-induced immobilization on the preservation muscle mass, strength, endurance. J Strength Cond Res 23(1): 116-120, 2009-Muscle strength loss will occur periods physical inactivity immobilization. Creatine may have a favorable effect mass independently exercise. The purpose this study was to determine effects upper-limb performance after Before study, creatine-naïve men (n = 7; 18-25 years)...
Abstract Background Age‐related sarcopenia is accelerated by physical inactivity. Low‐load resistance exercise (LLRE) counters inactivity‐induced muscle atrophy in older adults, but changes fibre morphology are unstudied. We aimed to determine the impact of LLRE during short‐term inactivity (step‐reduction) on size and capillarity as well satellite cell (SC) content skeletal muscle. Methods Fourteen (~71 years) male adults underwent 14 days step reduction (<1500 steps/day) while...
Abstract Cellular senescence is the irreversible arrest of normally dividing cells and driven by cell cycle inhibitors Cdkn2a , Cdkn1a Trp53 . Senescent are implicated in chronic diseases tissue repair through their increased secretion pro‐inflammatory factors known as senescence‐associated secretory phenotype (SASP). Here, we use spatial transcriptomics single‐cell RNA sequencing (scRNAseq) to demonstrate that displaying senescent characteristics “transiently” present within regenerating...
The role of angiotensin II (Ang II) in skeletal muscle is poorly understood. We report that pharmacological inhibition Ang signaling or ablation the AT1a receptor significantly impaired growth following myotrauma, vivo, likely due to satellite cell activation and chemotaxis. In vitro experiments demonstrated treatment activated quiescent myoblasts as evidenced by upregulation myogenic regulatory factors, increased number β-gal+, Myf5-LacZ acquisition cellular motility. Furthermore, exogenous...
A paucity of information exists regarding the presence local renin—angiotensin systems (RASs) in skeletal muscle and associated stem cells. Skeletal cells were isolated from C57BL/6 mice examined for a RAS using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC), Western blotting liquid chromatography-mass spectrometry (LC-MS). Furthermore, effect mechanical stimulation on member gene expression was analysed. Whole muscle, primary myoblasts...
Streptozotocin (STZ) is used extensively to induce pancreatic beta-cell death and ultimately diabetes mellitus in animal models. However, the direct effects of STZ on muscle are largely unknown. To delineate from hypoinsulinemia/hyperglycemia, we injected young rats with 1) saline (control), 2) (120 mg/kg) or 3) insulin (STZ-INS; maintain euglycemia). demonstrated significantly elevated blood glucose throughout 48-h protocol, while control STZ-INS were euglycemic. Body mass increased (13 +/-...
Long duration spaceflight missions will require novel exercise systems to protect astronaut crew from the detrimental effects of microgravity exposure. The SPRINT protocol is a and promising prescription that combines aerobic resistive training using flywheel device, it was successfully employed in 70-day bed-rest study as well onboard International Space Station. Our team created VR simulation further augment when ergometer device (the Multi-Mode Exercise Device or M-MED). aspired maximal...
The role of angiotensin II (ANG II) in postnatal vasculogenesis and angiogenesis during skeletal muscle (SKM) regeneration is unknown. We examined the capacity ANG to stimulate capillary formation growth cardiotoxin-induced ACE inhibitor-treated type 1a receptor knockout (AT1a(-/-)) C57Bl/6 control mice. Analysis tibialis anterior (TA) cross-sections revealed 17% 23% reductions capillarization AT1a(-/-) captopril treated mice, respectively, when compared with controls, 21 days postinjury....
Here, we asked whether could identify pharmacological agents that enhance endogenous stem cell function to promote skin repair, focusing on skin-derived precursors (SKPs), a dermal precursor population. Libraries of compounds already used in humans were screened for their ability the self-renewal human and rodent SKPs. We identified validated five such compounds, showed two them, alprostadil trimebutine maleate, enhanced repair full thickness wounds middle-aged mice. Moreover, SKPs isolated...
Cellular senescence is the irreversible arrest of normally dividing cells and driven by cell cycle inhibitory proteins such as p16, p21, p53. When enter senescence, they secrete a host proinflammatory factors known senescence-associated secretory phenotype, which has deleterious effects on surrounding tissues. Little role in Duchenne muscular dystrophy (DMD), fatal X-linked neuromuscular disorder typified chronic inflammation, extracellular matrix remodeling, progressive loss muscle mass...
Skeletal muscle repair and maintenance are directly indirectly supported by interstitial cell populations such as vascular cells fibro-adipogenic progenitors (FAPs), a subset of which express Twist2 possess direct myogenic potential. Furthermore, work in rodents has highlighted the potential pericytes to act progenitor cells, giving rise transdifferentiating into endothelial cells. However, less is understood about these human skeletal muscle. Here, we performed single-cell RNA sequencing...
The exploration of space will require ever-increasing exposure to microgravity environments. human response this has been categorized and mitigated via countermeasures, principally exercise. However, additional constraints future mission design minimizes the allotted modalities for exercise, creating a risk psychological fatigue, reduction in motivation, suite other categorical factors that could, taken together, present reduced adherence countermeasures and/or performance. Thus, current...
The role of ANG II in skeletal muscle and satellite cell regulation is largely unknown. Cardiotoxin (CTX) was used to investigate whether injury activates a local signaling system. Following injury, immunohistochelmistry (IHC) analysis revealed robust increase the intensity angiotensinogen angiotensin type 1 (AT(1)) receptor expression. As regeneration proceeded, however, AT(1) were downregulated. Nuclear accretion fiber formation also assessed during mice treated with captopril (an...
Animals such as amphibians have an incredible capacity for regeneration with some being able to regrow their tail or appendages. Although mammalian tissues like the skin and bones can repair following injury, there are only a few examples of true multilineage regeneration, including distal portion digit tip. In both mammals, however, achieve successful it is now appreciated that intact nerve innervation necessity. Here, we review current state literature discuss recent advances identify...
Skeletal muscle is maintained and repaired by sub-laminar, Pax7-expressing satellite cells. However, recent mouse investigations have described a second myogenic progenitor population that resides within the myofiber interstitium expresses transcription factor Twist2. Twist2-expressing cells exclusively repair maintain type IIx/b fibers. Currently, it unknown if are present in human skeletal they function as progenitors. Here, we perform combination of single-cell RNA sequencing analysis...