Cardiogenol C can induce Mouse Hair Bulge Progenitor Cells to Transdifferentiate into Cardiomyocyte-like Cells

<p>Abstract</p> <p>Background</p> <p>Hair bulge progenitor cells (HBPCs) are multipotent stem cells derived from the bulge region of mice vibrissal hairs. The purified HBPCs express CD34, K15 and K14 surface markers. It has been reported that HBPCs could be readily induced to transdifferentiate into adipocytes and osteocytes. However, the ability of HBPCs to transdifferentiate into cardiomyocytes has not yet been investigated.</p> <p>Methodology/Principal Findings</p> <p>The cardiomyogenic potential of HBPCs was investigated using a small cell-permeable molecule called Cardiogenol C. We established that Cardiogenol C could induce HBPCs to express transcription factors GATA4, Nkx2.5 and Tbx5, which are early specific markers for pre-cardiomyogenic cells. In prolonged cultures, the Cardiogenol C-treated HBPCs can also express muscle proteins, cardiac-specific troponin I and sarcomeric myosin heavy chain. However, we did not observe the ability of these cells to functionally contract. Hence, we called these cells cardiomyocyte-like cells rather than cardiomyocytes. We tried to remedy this deficiency by pre-treating HBPCs with Valproic acid first before exposing them to Cardiogenol C. This pretreatment inhibited, rather than improved, the effectiveness of Cardiogenol C in reprogramming the HBPCs. We used comparative proteomics to determine how Cardiogenol C worked by identifying proteins that were differentially expressed. We identified proteins that were involved in promoting cell differentiation, cardiomyocyte development and for the normal function of striated muscles. From those differentially expressed proteins, we further propose that Cardiogenol C might exert its effect by activating the Wnt signaling pathway through the suppression of Kremen1. In addition, by up-regulating the expression of chromatin remodeling proteins, SIK1 and Smarce1 would initiate cardiac differentiation.</p> <p>Conclusions/Significance</p> <p>In conclusion, our CD34⁺/K15⁺HBPCs could be induced to transdifferentiate into cardiomyocyte-like cells using a small molecule called Cardiogenol C. The process involves activation of the Wnt signaling pathway and altered expression of several key chromatin remodeling proteins. The finding is clinically significant as HBPCs offer a readily accessible and autologous source of progenitor cells for cell-based therapy of heart disease, which is one of major killers in developed countries.</p

A Protective Mechanism against Antibiotic-Induced Ototoxicity: Role of Prestin

Hearing loss or ototoxicity is one of the major side effects associated with the use of the antibiotics, particularly aminoglycosides (AGs), which are the most commonly used antibiotics worldwide. However, the molecular and cellular events involved in the antibiotic-induced ototoxicity remains unclear. In the present study, we test the possibility that prestin, the motor protein specifically expressed in the basolateral membrane of outer hair cells (OHCs) in the cochlea with electromotility responsible for sound amplification, may be involved in the process of AG-induced apoptosis in OHCs. Our results from both mice model and cultured cell line indicate a previously unexpected role of prestin, in mediating antibiotic-induced apoptosis, the effect of which is associated with its anion-transporting capacity. The observed downregulation of prestin mRNA prior to detectable apoptosis in OHCs and hearing loss in the antibiotic-treated mice is interesting, which may serve as a protective mechanism against hearing loss induced by AGs in the early stage

Elevated expression of TDP-43 in the forebrain of mice is sufficient to cause neurological and pathological phenotypes mimicking FTLD-U

TDP-43 is a multifunctional DNA/RNA-binding factor that has been implicated in the regulation of neuronal plasticity. TDP-43 has also been identified as the major constituent of the neuronal cytoplasmic inclusions (NCIs) that are characteristic of a range of neurodegenerative diseases, including the frontotemporal lobar degeneration with ubiquitin+ inclusions (FTLD-U) and amyotrophic lateral sclerosis (ALS). We have generated a FTLD-U mouse model (CaMKII-TDP-43 Tg) in which TDP-43 is transgenically overexpressed in the forebrain resulting in phenotypic characteristics mimicking those of FTLD-U. In particular, the transgenic (Tg) mice exhibit impaired learning/memory, progressive motor dysfunction, and hippocampal atrophy. The cognitive and motor impairments are accompanied by reduced levels of the neuronal regulators phospho–extracellular signal-regulated kinase and phosphorylated cAMP response element-binding protein and increased levels of gliosis in the brains of the Tg mice. Moreover, cells with TDP-43+, ubiquitin+ NCIs and TDP-43–deleted nuclei appear in the Tg mouse brains in an age-dependent manner. Our data provide direct evidence that increased levels of TDP-43 protein in the forebrain is sufficient to lead to the formation of TDP-43+, ubiquitin+ NCIs and neurodegeneration. This FTLD-U mouse model should be valuable for the mechanistic analysis of the role of TDP-43 in the pathogenesis of FTLD-U and for the design of effective therapeutic approaches of the disease

Blended Learning in Anatomy Teaching for Non-Medical Students: An Innovative Approach to the Health Professions Education

Purpose: Anatomy is a basic science for health professions curricula. Recent research suggests that the innovative blended learning approach (classroom learning plus use of online learning) outperforms conventional didactic teaching by facilitating effective learning. This study explores the feasibility of adopting blended learning in anatomy teaching and evaluates the learning experiences of students. Method: Courseware called electronic Professional Study (ePS) was developed and used for teaching anatomy of the cardiovascular system for non-medical students. ePS composed of three condensed, recorded course lectures, revision guides, and gamified quizzes. These were placed on the Web platform for students to watch before didactic lecture. Scheduled class periods were dedicated to participating in active-learning exercises. By the end of the academic semester, the courseware evaluation was implemented using a set of 5-point Likert scale questions. The e-questionnaire was distributed to a convenience sample of Year-2 full-time undergraduate students majoring in pharmacy enrolled in an introductory course in anatomy and physiology. Multiple linear regression was conducted to examine the relationship between courseware usage and examination results. Results: All enrolled students (n = 53) completed and returned the questionnaire. About 38% used the courseware less than ten times during the semester, and 7.5% never used it. e-Questionnaire shows that a majority agreed that the courseware content was clearly presented and easy to navigate. Multiple regression shows that courseware usage did not contribute significantly to the performance. Conclusions: Blended learning was perceived positively by most students. However, no effect on learning could be established. Keywords: Anatomy, Health profession education, Micro-module, Medical education, e-learning Courseware, Gamification, Hong Kon

Integrative Analysis of the Developing Postnatal Mouse Heart Transcriptome

<div><p>In mammals, cardiomyocytes rapidly proliferate in the fetus and continue to do so for a few more days after birth. These cardiomyocytes then enter into growth arrest but the detailed molecular mechanisms involved have not been fully elucidated. We have addressed this issue by comparing the transcriptomes of 2-day-old (containing dividing cardiomyocytes) with 13-day-old (containing growth arrested cardiomyocytes) postnatal mouse hearts. We performed comparative microarray analysis on the heart tissues and then conducted Functional annotation, Gene ontology, KEGG pathway and Gene Set enrichment analyses on the differentially expressed genes. The bioinformatics analysis revealed that gene ontology categories associated with the “cell cycle”, “DNA replication”, “chromosome segregation” and “microtubule cytoskeleton” were down-regulated. Inversely, “immune response”, “extracellular matrix”, “cell differentiation” and “cell membrane” were up-regulated. Ingenuity Pathways Analysis (IPA) has revealed that GATA4, MYH7 and IGF1R were the key drivers of the gene interaction networks. In addition, Regulator Effects network analysis suggested that TASP1, TOB1, C1orf61, AIF1, ROCK1, TFF2 and miR503-5p may be acting on the cardiomyocytes in 13-day-old mouse hearts to inhibit cardiomyocyte proliferation and G1/S phase transition. RT-qPCR was used to validate genes which were differentially expressed and genes that play a prominent role in the pathways and interaction networks that we identified. In sum, our integrative analysis has provided more insights into the transcriptional regulation of cardiomyocyte exit from the cell cycle during postnatal heart development. The results also pinpoint potential regulators that could be used to induce growth arrested cardiomyocytes to proliferate in the infarcted heart.</p></div

Top gene interaction network based on information from the Ingenuity Pathways Knowledge Base.

<p>Genes that are up- or down-regulated are labelled in red and green, respectively. Genes that are colored gray are not differentially expressed between Day 2 and Day 13.</p

KEGG pathway map of the cell cycle.

<p>Cell cycle associated genes are significantly enriched in the list of differentially expressed genes (p = 8.6 x 10⁻⁹). Fold change is only shown for genes within the list and illustrates near universal down-regulation in the pathway for cardiomyocytes in the 13-day-old heart, as compared with the 2-day-old heart. Arrows indicate positive regulation, while other lines indicate negative regulation.</p

KEGG pathway map of the cell cycle.

<p>Cell cycle associated genes are significantly enriched in the list of differentially expressed genes (p = 8.6 x 10⁻⁹). Fold change is only shown for genes within the list and illustrates near universal down-regulation in the pathway for cardiomyocytes in the 13-day-old heart, as compared with the 2-day-old heart. Arrows indicate positive regulation, while other lines indicate negative regulation.</p