bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcriptional Heterogeneity of Neural Stem Cells during Axolotl Salamander Spinal Cord Regeneration
Authors: Monaghan James , Jensen Tyler , Stein David , Mun Evan , Maden Malcolm 
Published: April 2020

Unlike humans, axolotl salamanders are capable of restoring sensory and motor function after spinal cord injury. Upon tail amputation or spinal cord transection, endogenous neural stem cells (NSCs) increase proliferation and differentiate into multiple neural and glial cell types of the central and peripheral nervous system. How NSCs transition from a resting state to a regenerative state and coordinate proper neural differentiation is poorly understood. Here, we study the global changes that occur in NSCs after spinal cord injury as well as specific changes in gene transcription as the NSC regenerative program unfolds. We first studied global changes in NSCs after injury by measuring global RNA synthesis temporally and spatially through incorporation of 5‐ethynyl‐uridine into nascent RNA. Substantial upward shifts in overall transcriptional output occurred in specific NSC populations during regeneration, which was correlated with loss of facultative repressive chromatin marks, and was dependent on Hippo‐YAP signaling. We also found an evolutionarily conserved upregulation of nascent RNA production in active neural progenitors in axolotls and mice. In order to dig deeper into neural stem cell dynamics during regeneration, we adopted multiplexed fluorescence in situ hybridization (FISH) in tissue section and whole mount tissues. We produced a user‐friendly, sharable, Docker Container for automated high‐throughput design of Third Generation Hybridization Chain Reaction (HCR) FISH probe sets. An advantage of HCR‐FISH is that it utilizes non‐enzymatic signal amplification, while maintaining low background signal, leading to high signal‐to‐noise detection of mRNAs. We demonstrate that the HCR‐FISH method is amenable to multiplexing through five sequential rounds of hybridization (SeqFISH). Using our probe design pipeline and HCR‐FISH, we imaged NSC activation and differentiation in tissue sections collected after injury using 15 simultaneously‐detected probe sets indicative to CNS and PNS cell types. Whole mount HCR‐FISH for three neural markers were also imaged simultaneously to assess NSC and neuron responses after injury. Overall, the genetic neuroanatomical mapping performed here using molecular classification of NSCs provides novel information on how NSCs respond to injury to repair a CNS injury.Support or Funding InformationThis project was funded by grants NSF 1656429, NSF 1558017, and NIH OD024909
Integrated Histology‐Pathology Medical Education: What is it Good For?
Authors: Pinder Karen E 
Published: April 2020

Medical schools around the world now teach foundational anatomical sciences using integrated methods that have improved the content relevance in medical training and are more consistent with physicians’ clinical reasoning and practice. As stewards of one of these foundational sciences, histology experts at the University of British Columbia (UBC) medical school have embraced a renewed and integrated curriculum. Specifically, we have restructured our undergraduate medical curriculum and implemented an innovative competency‐based integration of years one and two histology with a more perceptibly clinical discipline, pathology. Results from faculty experiences, student outcomes on formative integrated examinations and educational research data from student learning surveys demonstrate the pedagogical effectiveness of our foundational science‐clinical integration.The next step is to establish how this pre‐clinical integration allows our medical students to utilize foundational science knowledge in subsequent clinical training. That is, how can we demonstrate that the relevance and application of this integration extends beyond the pre‐clinical curriculum and into the clinical years? In other words, what is integrated histology‐pathology medical education good for?This session will explore one answer to this question by describing our method of mapping histology‐pathology milestones and exit competencies to clinical knowledge and skills in a manner that illustrates the importance of integrated teaching in medical education. That is, by using milestones and exit competency‐based clinical scenarios, we are able to demonstrate how our integrated foundational (histology) and clinical (pathology) medical science approach enables students to progress to the level of clinical expertise expected of all graduating physicians.Our methods, experiences and outcomes can extend to other foundational science/clinical disciplines partnerships, and this session will prove useful for both educators and clinicians who are exploring or implementing interdisciplinary integrations in both undergraduate and post‐graduate medical training.
Therapeutic Strategies for Full‐Thickness Wounds: Skin and Corneal Tissue‐Engineered Substitutes with Stem Cells
Authors: Germain Lucie 
Published: April 2020

The LOEX centre of Laval University is specialized in stem cells and tissue engineering. In addition to fundamental research, LOEX focuses on translational medicine to transfer the discoveries into better treatment for the patients. The LOEX self‐assembly approach of tissue engineering was designed to elaborate complex human living tissue substitutes. Autologous self‐assembled skin substitutes (SASSs) are produced to treat wounds of severely burned patients. The procedure is based on primary culturing dermal fibroblasts and keratinocytes from a few cm2 skin biopsy taken from an unaffected site. Then, dermal fibroblasts are cultured in the presence of ascorbic acid. They secrete and organize their own extracellular matrix (ECM) on which keratinocytes rebuild the epithelium. SASSs exhibit a well‐developed stratified cornified epithelium. The basement membrane is structured and favors long‐term preservation of stem cells in the basal layer of the tissue‐engineered epidermis. The dense collagen network of the tissue‐engineered dermis provides resistance and allow SASS manipulation. After transplantation of autologous SASSs on burn wounds, the graft take was excellent (90–100%). No significant contraction was observed in vivo after grafting. The presence of the ECM promoted a good healing and skin suppleness. SASS presented a well‐organized epidermis and stem cells were settled and maintained in the basal layer after grafting. A complete basement membrane with numerous hemidesmosomes was observed before and after grafting, supporting a strong cohesion between the dermis and epidermis. The integrity of the transplanted SASS persisted over time (1‐ to 8‐year follow‐up) with no defect in epidermal regeneration and no significant contracture. Minimal hypertrophic scars were only observed between SASS. Thus, SASSs provide permanent skin replacement for severe burns. These living substitutes comprising cells and extracellular matrix possess the capability of expanding with the child’s growth. We conclude that the TES produced by this approach is a promising skin substitute for resurfacing full‐thickness skin injury given its functional characteristics: minimal contraction after grafting and promotion of long‐term tissue regeneration. LOEX also used cultured epithelial corneal autografts (CECA), produced from a small biopsy of the limbal area containing stem cells, for the treatment of limbal stem cell deficiency. The first clinical trial is completed, 14 of the 15 patients treated improved their visual conditions. These regenerative medicine technologies pave the way for better treatment of rare diseases.Support or Funding InformationSupported by the Canadian Institutes for Health Research (CIHR), The Stem Cell Network, Fonds de Recherche du Québec en Santé (FRQS), Fondation des Pompiers du Québec pour les Grands Brûlés and the Cell and Tissue Therapy Network of the FRQS. LG is holder of the Canada Research Chair on Stem Cells and Tissue Engineering of CIHR.
The Anatomy of Cutaneous Wound Healing and Its Inhibition: From Mechanisms to Therapy
Authors: Tomic-Canic Marjana 
Published: April 2020

Cutaneous wound healing integrates multiple cellular processes (inflammation, migration, proliferation, barrier formation, matrix deposition and remodeling; differentiation) and harnesses function of many cell types (keratinocytes, fibroblasts, adipocytes, melanocytes), their cross‐talk to endothelial cells, macrophages, mast cells, platelets, peripheral neurons, local and circulating progenitors with a single goal to repair the tissue and restore barrier. Such organized process is tightly controlled in spatial and temporal manner by using complex signaling networks and micro‐environmental factors. Although this ability of skin to maintain its barrier and heal wounds is evolutionary conserved and maintained throughout a lifetime of an organism, it may fails due to various underlining issues. Chronic wounds, such as diabetic foot ulcers (DFUs) and venous leg ulcers (VLUs) represent a widespread unmet clinical challenge and major burden on healthcare systems worldwide. Development of diagnostic tools and treatment strategies is very slow in part due to lack of knowledge regarding the mechanisms of wound healing and its inhibition. We are using genomic approaches and patients’ biopsies to decipher molecular pathophysiology of these chronic wounds as well as molecular mechanisms by which various therapeutic approaches contribute to reprogramming of non‐healing into healing phenotype. Recent findings from primary cells generated from patients as well as transcriptional and mRNA/miRNA profiling revealed multiple new mechanisms that inhibit healing in patients and facilitated identification of wound tissue with repair capability. This chronic wound “genomic signature” includes key mediators of inflammatory response, DNA damage, and response to infection, and specific crosstalk between multiple cell types, revealing new targets and therapeutic approaches.Support or Funding InformationNIH AR060562, NR015649, NR013881 and DK119085
Protein glycosylation in neural crest epithelial‐to‐mesenchymal transition and migration
Authors: Nie Shuyi 
Published: April 2020

Neural crest epithelial‐to‐mesenchymal transition (EMT) and migration involves coordinated remodeling of cell‐cell and cell‐matrix adhesions. During this cell phase transition event, interactions between adhesive molecules need to be dynamically regulated. We recently explored the involvement of protein glycosylation in this process. Protein glycosylation is one of the most complexed, yet least studied types of post‐translational modification. By attaching various forms of oligosaccharide (glycan) on different sites of a protein, glycosylation can regulate protein function by modulating its interaction with other molecules. Through the employment of chemical inhibitors for protein glycosylation, we demonstrated that glycosylation is required for neural crest EMT and migration in frog embryos. To gain a comprehensive understanding of how different proteins are glycosylated during this process, we performed a glycoproteomic analysis at different stages of neural crest development. Through this approach, we identified numerous membrane and secreted proteins that are differentially glycosylated, which may contribute to the dynamic changes in cell‐cell and cell‐matrix interactions during neural crest EMT and migration. We focused on E‐cadherin, a well‐known player in EMT and cell migration, to determine the function of specific protein glycosylation in protein activity and consequently in neural crest cell behavior. Our analysis identified two glycosylation linkage sites on E‐cadherin. The two glycosylation sites were mutated individually or in combination, and the function of mutant E‐cadherin was compared with that of wild type E‐cadherin. Our results showed that mutant E‐cadherins were less effective in promoting neural crest cell migration and this was partly due to an increase in the strength of cell‐cell adhesion mediated by the mutan t proteins. Therefore, our findings suggest a new mechanism to fine‐tune the activity of cell adhesive molecules during EMT and migration.Support or Funding InformationNIH R00 DE022796, Georgia Tech Startup Fund
The importance of T and B cell immunity in the production of autoantibodies to the angiotensin II type I receptor and the pathophysiology associated with preeclampsia
Authors: LaMarca Babette 
Published: April 2020

Preeclampsia (PE), is estimated to affect 5–7% of all pregnancies in the US, is characterized by placental ischemia, chronic inflammation, endothelial dysfunction, systemic vasoconstriction, renal dysfunction, hypertension and IUGR. Despite being the leading cause of maternal and perinatal morbidity and death worldwide, the mechanisms underlying the pathogenesis of hypertension during PE remain unclear. PE women have elevated cytokines, autoantibodies activating the angiotensin II type I receptor (AT1‐AA), cytolytic Natural Killer cells and THelper 1 cells. We have shown that adoptive transfer of CD4+THelper 1 cells increases cytokines, B cells secreting autoantibodies leading to activated cytolytic NK cells and hypertension during pregnancy. Moreover, infusion of purified AT1‐AA activates renal and placental NK cells to cause placental and renal mitochondrial (mt) oxidative stress and dysfunction which contributes to many clinical features of PE including hypertension. Utilizing the Reduced uterine perfusion pressure (RUPP) pregnant rat, a model of PE, we have demonstrated placental ischemia to be an important stimulus for hypertension and many immune mechanisms involved in PE. One important unanswered question in PE research is the importance of B cells in the pathology of the disease, specifically memory B2 cells vs B1 cells in the production of AT1‐AA. Overall our data demonstrate the importance of immunological memory and THelper 1 cells in pathophysiology of PE. In addition to our published data I will present recent findings demonstrating the importance of B cells to secrete AT1‐AA causing hypertension and many clinical features associated with PE.Support or Funding InformationRO1HD067541 and P20GM121334
Self‐sustaining Laboratories and Collaborative Mentoring in Anatomy Research
Authors: Salinas-Alvarez Yolanda , Quiroga-Garza Alejandro , Elizondo-Omaña Rodrigo Enrique , Guzman-Lopez Santos 
Published: April 2020

The development of new technologies and tools for teaching anatomy and the high cost of anatomy laboratories have forced a tendency to decrease the use of bodies and practice. However, these are essential for teaching gross anatomy, and their value is indisputable; students can understand anatomy and develop surgical and clinical skills. Our laboratory has been structured in a manner it can cover all student activities, but also be self‐sustaining through the implementation of postgraduate courses, host for clinical practices for specialists, and pharmaceutical sponsored courses. The incomes are then re‐invested in furthering the laboratory equipment (ultrasound, fluoroscopy, arthroscopy, microsurgery, minimally invasive surgery), to offer a wider range of courses for physicians to expand their knowledge and clinical practice.These equipments for the laboratory are also used to offer courses for near‐peers that aid in the Anatomy Department. Courses are also made specifically for the anatomy research group (GIA – Grupo de Investigación en Anatomía) students, oriented to areas of interest. Through a tightly organized and collaborative mentoring structure, the group with 17 years of experience, has grown and inspired its members into research. Mentors and mentees benefit from scientific production, enhanced research skill training, and combined experience. Scientific output has increased steadily over time, demonstrating an effective method with longitudinal results of its effectiveness. The group promotes scientific publications in indexed journals, with the students as first authors. The mentor‐mentee relationships are nurtured causing appreciation and recognition bilaterally. Most students wish to continue with a clinical residency, however, most report they wish to continue with some form of clinical research.Support or Funding InformationNone
Impact of the GH‐IGF Axis on Adipose Tissue and Obesity: Are there Benefits of Endocrine Defects
Authors: Kopchick John 
Published: April 2020

Disruption of the mouse growth hormone receptor gene (GHR−/−) results in dwarf, obese, GH resistant mice that possess low levels of IGF‐1 and high levels of GH with intense insulin sensitivity. These mice are similar to humans with Laron Syndrome (LS) in which the individuals are small in stature with low IGF‐1 and high GH levels. Cancer and diabetes rates in both the GHR−/− mice and LS individuals are low or non‐existent. In this regard, GHR−/− mice have extended longevity, in fact, they are the longest‐lived laboratory mouse. Thus, a defect in the action of GH may be beneficial for increased health‐span and longevity. In attempts to dissect which, if any, of the insulin sensitive tissue contribute to the extended health and lifespan of these mice, we have individually disrupted the GHR gene in liver, muscle, and adipose tissue. Surprisingly, only muscle specific GHR gene disruption resulted in a modest increase in life span while none of the others have the impressive extended longevity seen in GHR−/− mice. Since a decrease in the GH/IGF‐1 axis is important for extended health and lifespan, the ability to down regulate its action in adult life may be beneficial. To that end we have, and are, attempting to disrupt the mouse GHR in adult life. To date, disruption at 6 weeks of age results in female mice with extended longevity. Experiments to ‘knock‐out’ the GHR gene at 6 months and one year are ongoing. Also, since adipose tissue (AT) is metabolically important, data regarding the location and function of AT in these mice will be presented.Support or Funding InformationThis work was and supported by the State of Ohio’s Eminent Scholar Program that includes a gift by Milton and Lawrence Goll, the AMVETS, and NIH R01AG059779.
Neuroanatomical characterization of angiotensin‐sensitive neurons within the paraventricular nucleus of the hypothalamus reveals an access point for controlling behavioral and physiological responses to stress.
Authors: Krause Eric G. 
Published: April 2020

Stressors perceived in the environment or those arising from the internal milieu create neural signals that converge on the paraventricular nucleus of the hypothalamus (PVN). The PVN contains distinct neuronal phenotypes that integrate and transduce these signals into cardiovascular, neuroendocrine and behavioral responses that cope with the impact of psychological and physiological stress. Accumulating evidence implicates angiotensin receptors within the PVN as mediators of the stress response; however, the neuroanatomical mechanisms underlying these effects are not completely understood. Here, we use the Cre‐LoxP system in mice with virally‐mediated gene transfer and optogenetics to characterize the structure and function of neurons in the PVN that express the angiotensin type 1a receptor (Agtr1a). Neuroanatomical experiments discovered that Agtr1a(s) were expressed on neurons in the PVN that synthesize mRNAs for corticotropin‐releasing‐hormone (CRH) or thyroid‐releasing‐hormone (TRH). These CRH and TRH neurons were found to send direct axonal projections to the median eminence and their optogenetic excitation increased, but inhibition decreased, circulating levels of corticosterone and thyroxine, indicating that Agtr1a‐expressing neurons in the PVN control the activity of neuroendocrine axes. To investigate how angiotensin signaling may affect stress responding, we engineered mice with Agtr1a specifically deleted from the PVN (Agtr1a‐PVN KO). Under basal conditions, no effect of the deletion was observed; however, maintenance on high fat diet, a metabolic stressor, revealed a gene x environment interaction whereby Agtr1a‐PVN KO mice had increased adiposity and body weight but lower blood pressure relative to controls. In psychogenic stress paradigms, Agtr1a‐PVN KO mice were found to have slight but significant decreases in anxiety‐like behavior and cardiovascular reactivity. Collectively, these results suggest that stimulation of Agtr1a(s) in the PVN contribute to activation of neuroendocrine axes that mediate behavioral and physiological responses to metabolic and psychogenic stressors.Support or Funding InformationNIH: HL122494, HL139868, HL136595
Hypothalamic Regulation of Blood Pressure
Authors: Lazartigues Eric D. 
Published: April 2020

In addition to brainstem nuclei well‐known to be involved in baroreflex regulation of blood pressure, several hypothalamic regions have also been shown to modulate autonomic regulation and cardiovascular function. Among them, the paraventricular nucleus (PVN) comprised of magnocellular neurons involved in vasopressin and oxytocin secretion and parvocellular neurons involved in pre‐sympathetic activity. Elevated firing activity of pre‐sympathetic PVN neurons is thought to contribute to hypertension. The PVN also contains components of the renin‐angiotensin system (RAS), like the angiotensin‐II type 1 receptor (AT1R) which expression is enhanced in hypertensive conditions. We previously reported that Angiotensin converting enzyme 2 (ACE2) is also expressed in the PVN and capable of metabolizing Ang‐II levels thus reducing Ang‐II pro‐hypertensive signaling. More recently, we identified ADAM17 as a critical mediator of AT1R downstream signaling, supporting the maintenance of hypertension and neuro‐inflammation. We observed that during RAS overactivity, AT1R stimulation leads to translocation of ADAM17 from the cytoplasm to the plasma membrane, leading to enhanced activity of this sheddase. As a result, ACE2 is cleaved by ADAM17 from the plasma membrane and the compensatory activity of the enzyme is thus compromised, promoting an imbalance of autonomic function and favoring the development of neurogenic hypertension. Recently, we investigated the interaction of AT1R, ADAM17 and ACE2 on PVN pre‐sympathetic neurons and hypothesized that ADAM17 would impair ACE2 regulation of neuronal activity on these cells, leading to an increase in sympathetic outflow and eventually blood pressure. We also attempted to identify patterns of expression for these RAS components on specific PVN neurons. To address these questions, we relied on novel transgenic mouse models with selective deletion of RAS components in the PVN and electrophysiology. Our observations suggest that ACE2 maintains inhibitory neurotransmission into the PVN and its expression is prevalent on inhibitory neurons. On the other hand, ADAM17 is critical for Ang II‐mediated activation of kidney‐related presympathetic glutamatergic neurons in the PVN, confirming the supportive role of ADAM17 in increasing presympathetic neuronal activity. Balancing inhibitory and excitatory neurotransmission from the PVN is essential to prevent a sympathetic overdrive and our observations provide new targets to modulate excessive sympathetic activity in hypertension.Support or Funding InformationNHLBI HL093178.