Quantitative Proteomic Profile Reveals Essential Factors during Heart Regeneration in Adult Xenopus tropicalis

Cardiovascular heart failure is a pathophysiological state in which the heart cannot consume enough blood flow to meet the basic needs of the body. According to clinical classification, heart failure can be divided by pathological or functional subtypes. Pathological heart failure includes the pressure-induced or volume-induced heart failure. Functional heart failure includes can divided by right or left in circulatory system, also can be divided by systolic or diastolic underlying the cardiac function. During the onset of chronic cardiovascular diseases, myocardial function is gradually damaged. In mammals, the embryonic and neonatal hearts harbor capacities to repair after the injury or damage. However, the regeneration capacity rapidly disappeared within one week after birth. Xenopus tropicalis is an amphibian species that phylogenetically close to mammals but remained its well regeneration capability in heart. Previous study showed well regenerated capability in the heart of Xenopus tropicalis. There is nearly no scar and fibrotic tissue left in the injured area after 30 to 60 days of apical resection.According to the characteristic being revealed in the Xenopus model, our laboratory has setup a heart regeneration model to elucidate the mechanism as to how the Xenopus tropicalis regenerated its heart after apical resection. The isobaric tags for relative and absolute quantitation and tandem mass tag (iTRAQ and TMT) mass spectrometry techniques are used to investigate the underlying mechanism of Xenopus heart regeneration. The heatmap profile helped reveal the up and down regulated proteins during the regeneration process. The expression pattern values could be generated as a protein list to complete further analysis. In our findings, the top 15 pathways from day 1 to day 3 after surgery samples involved pathways such as neutrophil degranulation and apoptosis have showed the activation of immunity in the Xenopus tropicalis. The 4th to 16th days' pathway analysis indicated that the immune responses were being reduced and translation related molecular activity became abundant. Our aim is to learn the underlying mechanisms from the regeneration system of Xenopus, and the difference of signaling pathways that triggered the cardiomyocytes re-entry to the cell cycle which will lead to the cardiomyocyte proliferation.In summary, the mass spectrometry results provided an insight into the protein alternation after Xenopus heart surgery. Our mass spectrometry results also indicated that the regeneration in heart is a complicated process which not only needs the activation of the immunity but also needs the reduction on ROS responses and the regulation to the transcriptional networks and protein translation. This project will further focus on whether cardiomyocyte proliferation and the novel targets, such as the antioxidants and the immune signals, which contributes to the heart regeneration capability in Xenopus based on the mass spectrometry results.心血管疾病位列全球十大死因之首，5690萬人中就有1520萬人因缺血性心臟疾病或心肌梗塞而造成死亡。心血管疾病通常導致心肌受損，但哺乳類的心臟修復能力卻十分有限。兩棲類在進化上與哺乳類親緣關係較近，並且具有較強的心臟修復能力，是研究心臟修復與再生的優秀模型。因此我們使用模式動物非洲爪蛙，建立一手術切除心臟尖端的模型。實驗發現非洲爪蛙在心尖手術切除後，具有修復及再生的能力；進一步利用此模型了解兩棲類所保留的心臟修復機制。將手術後不同時間點的樣本通過化學同位素標記(Isobaric tags for relative and absolute quantitation, iTRAQ 和 tandem modified tag, TMT) 的方法進行定量分析。在手術後1至3天的樣本中所富集到的前15種細胞信號通路包含了中性顆粒細胞脫粒、細胞凋亡、免疫反應等多項細胞信號通路，說明早期創口引起了非洲爪蛙的免疫響應。而手術後4至16天的樣本檢測結果顯示，免疫反應逐漸減弱，而細胞翻譯水平開始上升，表明修復過程正在發生。同位素定量分析的結果展現了非洲爪蛙心尖修復及再生過程中分子的動態變化。我們進一步希望通過定量分析結果探究心肌細胞修復及再生的分子機制，以及誘導心肌細胞重新進入細胞分化周期的關鍵因素。綜上所述，質譜分析結果繪製了非洲爪蛙的心臟手術後蛋白質動態變化的全景圖。我們的結果還表明，心臟的再生是一個複雜的過程，不僅需要激活免疫過程參與，還需要減少對ROS的反應，調節轉錄網絡和蛋白質翻譯。本研究將根據質譜分析結果，進一步研究心肌細胞的增殖以及促進心肌細胞增殖的方式，例如探究抗氧化劑和免疫因子，是否有助於提高非洲爪蛙的心臟再生能力。LIN, Yi-jyun.Ph.D. Chinese University of Hong Kong 2021.Includes bibliographical references (leaves )Abstracts in English and Chinese.Title from PDF title page (viewed on ...