Molecular Biology and Stem Cell Biology Lab, Centre for Molecular and Nanomedical Sciences, International Research Centre, Sathyabama Institute of Science and Technology (Deemed to Be University), Jeppiaar Nagar, SH 49A, Chennai, Tamil Nadu, 621306, India.
Department of Biotechnology, Alagappa University, Karaikudi, Tamil Nadu, India.
In Vitro Cell Dev Biol Anim. 2024 Mar;60(3):222-235. doi: 10.1007/s11626-023-00843-6. Epub 2024 Mar 19.
Regeneration is a multifaceted biological phenomenon that necessitates the intricate orchestration of apoptosis, stem cells, and immune responses, culminating in the regulation of apoptosis-induced compensatory proliferation (AICP). The AICP context of research is observed in many animal models like in Hydra, Xenopus, newt, Drosophila, and mouse but so far not reported in earthworm. The earthworm Perionyx excavatus is used in the present study to understand the relationship between AICP-related protein expression and regeneration success in different conditions (normal regeneration and abnormal multiple bud formation). Initially, the worms are amputated into five equal portions and it is revealed that regeneration in P. excavatus is clitellum independent and it gives more preference for anterior regeneration (regrowth of head portion) than for posterior regeneration (regrowth of tail portion). The posterior segments of the worm possess enormous regeneration ability but this is lacking in anterior segments. Alkaline phosphate, a stem cell marker, shows strong signals throughout all the posterior segments but it decreases in the initial 1st to 15th anterior segments which lack the regeneration ability. While regenerating normally, it was suggested that the worm follow AICP principles. This is because there was increased expression of apoptosis signals throughout the regeneration process along with constant expression of stem cell proliferation response together with cellular proliferation. In amputated posterior segments maintained in vitro, the apoptosis signals were extensively detected on the 1st day. However, on the 4th and 6th days, caspase-3 and H2AX expression are significantly suppressed, which may eventually alter the Wnt3a and histone H3 patterns that impair the AICP and result in multiple bud formation. Our results suggest that AICP-related protein expression pattern is crucial for initiating proper regeneration.
再生是一种多方面的生物学现象，需要细胞凋亡、干细胞和免疫反应的精细协调，最终调节细胞凋亡诱导的代偿性增殖（AICP）。在许多动物模型中，如 Hydra、Xenopus、newt、Drosophila 和 mouse 中都观察到了 AICP 研究背景，但到目前为止，在蚯蚓中尚未报道。本研究使用 Perionyx excavatus 蚯蚓来了解 AICP 相关蛋白表达与不同条件（正常再生和异常多芽形成）下再生成功之间的关系。最初，将蚯蚓切成五个相等的部分，结果表明 P. excavatus 的再生与环带无关，它更倾向于前部再生（头部部分的再生）而不是后部再生（尾部部分的再生）。蚯蚓的后段具有巨大的再生能力，但前段缺乏这种能力。碱性磷酸酶是一种干细胞标志物，在所有后段都显示出强烈的信号，但在前 15 个缺少再生能力的前段中信号减弱。在正常再生过程中，蚯蚓遵循 AICP 原则。这是因为在整个再生过程中，凋亡信号增加，同时干细胞增殖反应和细胞增殖持续表达。在体外维持的截肢后段中，第 1 天广泛检测到凋亡信号。然而，在第 4 天和第 6 天，caspase-3 和 H2AX 的表达显著受到抑制，这最终可能改变 Wnt3a 和组蛋白 H3 模式，损害 AICP，并导致多芽形成。我们的研究结果表明，AICP 相关蛋白表达模式对于启动适当的再生至关重要。
