TY - JOUR T1 - Cytoplasmic poly (A)-binding protein critically regulates epidermal maintenance and turnover in the planarian . JF - Development Y1 - 2017 A1 - Bansal, Dhiru A1 - Kulkarni, Jahnavi A1 - Nadahalli, Kavana A1 - Lakshmanan, Vairavan A1 - Krishna, Srikar A1 - Sasidharan, Vidyanand A1 - Geo, Jini A1 - Dilipkumar, Shilpa A1 - Pasricha, Renu A1 - Gulyani, Akash A1 - Raghavan, Srikala A1 - Palakodeti, Dasaradhi KW - Animals KW - Cell Lineage KW - Cell Proliferation KW - Cytoplasm KW - Epidermis KW - Epithelium KW - Extracellular Matrix KW - Gene Knockdown Techniques KW - Homeostasis KW - Models, Biological KW - Planarians KW - Poly(A)-Binding Protein I KW - Regeneration KW - RNA, Messenger KW - Wound Healing AB -

Identifying key cellular events that facilitate stem cell function and tissue organization is crucial for understanding the process of regeneration. Planarians are powerful model system to study regeneration and stem cell (neoblast) function. Here, using planaria, we show that the initial events of regeneration, such as epithelialization and epidermal organization are critically regulated by a novel cytoplasmic poly A-binding protein, SMED-PABPC2. Knockdown leads to defects in epidermal lineage specification, disorganization of epidermis and ECM, and deregulated wound healing, resulting in the selective failure of neoblast proliferation near the wound region. Polysome profiling suggests that epidermal lineage transcripts, including , are translationally regulated by SMED-PABPC2 Together, our results uncover a novel role for SMED-PABPC2 in the maintenance of epidermal and ECM integrity, critical for wound healing and subsequent processes for regeneration.

VL - 144 IS - 17 ER - TY - JOUR T1 - A quantitative metabolomics peek into planarian regeneration. JF - Analyst Y1 - 2015 A1 - Natarajan, Nivedita A1 - Ramakrishnan, Padma A1 - Lakshmanan, Vairavan A1 - Palakodeti, Dasaradhi A1 - Rangiah, Kannan KW - Animals KW - Calibration KW - Chromatography, High Pressure Liquid KW - Limit of Detection KW - Metabolomics KW - Planarians KW - Reference Standards KW - Regeneration KW - Reproduction, Asexual KW - Species Specificity KW - Tandem Mass Spectrometry AB -

The fresh water planarian species Schmidtea mediterranea is an emerging stem cell model because of its capability to regenerate a whole animal from a small piece of tissue. It is one of the best model systems to address the basic mechanisms essential for regeneration. Here, we are interested in studying the roles of various amines, thiols and nucleotides in planarian regeneration, stem cell function and growth. We developed mass spectrometry based quantitative methods and validated the differential enrichment of 35 amines, 7 thiol metabolites and 4 nucleotides from both intact and regenerating planarians. Among the amines, alanine in sexual and asparagine in asexual are the highest (>1000 ng/mg) in the intact planarians. The levels of thiols such as cysteine and GSH are 651 and 1107 ng mg(-1) in planarians. Among the nucleotides, the level of cGMP is the lowest (0.03 ng mg(-1)) and the level of AMP is the highest (187 ng mg(-1)) in both of the planarian strains. We also noticed increasing levels of amines in both anterior and posterior regenerating planarians. The blastema from day 3 regenerating planarians also showed higher amounts of many amines. Interestingly, the thiol (cysteine and GSH) levels are well maintained during planarian regeneration. This suggests an inherent and effective mechanism to control induced oxidative stress because of the robust regeneration and stem cell proliferation. Like in intact planarians, the level of cGMP is also very low in regenerating planarians. Surprisingly, the levels of amines and thiols in head regenerating blastemas are ∼3 times higher compared to those for tail regenerating blastemas. Thus our results strongly indicate the potential roles of amines, thiols and nucleotides in planarian regeneration.

VL - 140 IS - 10 ER -