@article {2109, title = {Modulation of β-catenin levels regulates cranial neural crest patterning and dispersal into first pharyngeal arch.}, journal = {Dev Dyn}, year = {2020}, month = {2020 May 19}, abstract = {

BACKGROUND: Vertebrate cranial neural crest cells (CNCCs) are multipotent, proximal to the source CNCC form the cranial ganglia. Distally, in the pharyngeal arches, they give rise to the craniofacial skeleton and connective tissues. Fate choices are made as CNCC pattern into distinct destination compartments. In spite of this importance, the mechanism patterning CNCC is poorly defined.

RESULTS: Here, we report that a novel β-catenin-dependent regulation of N-Cadherin levels may drive CNCC patterning. In mouse embryos, at the first pharyngeal arch axial level, membrane β-catenin levels correlate with the extent of N-cadherin-mediated adhesion and thus suggest the presence of collective and dispersed states of CNCC. Using in vitro human neural crest model and chemical modulators of β-catenin levels, we show a requirement for down-modulating β-catenin for regulating N-cadherin levels and cell-cell adhesion. Similarly, in β-catenin gain-of-function mutant mouse embryos, CNCC fail to lower N-cadherin levels. This indicates a failure to reduce cell-cell adhesion, which may underlie the failure of mutant CNCC to populate first pharyngeal arch.

CONCLUSION: We suggest that β-catenin-mediated regulation of CNCC adhesion, a previously underappreciated mechanism, underlies the patterning of CNCC into fate-specific compartments.

}, issn = {1097-0177}, doi = {10.1002/dvdy.208}, author = {Javali, Alok and Lakshmanan, Vairavan and Palakodeti, Dasaradhi and Sambasivan, Ramkumar} } @article {1734, title = {Characterization of new variant human ES line VH9 hESC (INSTEMe001-a): a tool for human stem cell and cancer research.}, journal = {Stem Cell Res}, volume = {37}, year = {2019}, month = {2019 May}, pages = {101444}, abstract = {

Human pluripotent stem cells (hPSCs) acquire changes at the genomic level upon proliferation and differentiation (Peterson and Loring, 2014). Studies from International Stem Cell Initiative and independent laboratories identified a copy number variant (CNV) in hES cell lines displaying a normal karyotype, which provided a selective advantage to hES cells in culture. In our laboratory we have identified variant H9-hESC (derived from H9-hESC) with normal karyotype, pluripotency expression, differentiation profile but with altered traits of high cell survival and low E-CADHERIN expression.

}, issn = {1876-7753}, doi = {10.1016/j.scr.2019.101444}, author = {Arasala, Radhika Rao and Jayaram, Manjunath and Chattai, Jagamohan and Kumarasamy, Thangaraj and Sambasivan, Ramkumar and Rampalli, Shravanti} } @article {1581, title = {Infectivity of adeno-associated virus serotypes in mouse testis.}, journal = {BMC Biotechnol}, volume = {18}, year = {2018}, month = {2018 Nov 01}, pages = {70}, abstract = {

BACKGROUND: Recombinant adeno-associated viruses (AAVs) are emerging as favoured transgene delivery vectors for both research applications and gene therapy. In this context, a thorough investigation of the potential of various AAV serotypes to transduce specific cell types is valuable. Here, we rigorously tested the infectivity of a number of AAV serotypes in murine testis by direct testicular injection.

RESULTS: We report the tropism of serotypes AAV2, 5, 8, 9 and AAVrh10 in mouse testis. We reveal unique infectivity of AAV2 and AAV9, which preferentially target intertubular testosterone-producing Leydig cells. Remarkably, AAV2 TM, a mutant for capsid designed to increase transduction, displayed a dramatic alteration in tropism; it infiltrated seminiferous tubules unlike wildtype AAV2 and transduced Sertoli cells. However, none of the AAVs tested infected spermatogonial cells.

CONCLUSIONS: In spite of direct testicular injection, none of the tested AAVs appeared to infect sperm progenitors as assayed by reporter expression. This lends support to the current view that AAVs are safe gene-therapy vehicles. However, testing the presence of rAAV genomic DNA in germ cells is necessary to assess the risk of individual serotypes.

}, issn = {1472-6750}, doi = {10.1186/s12896-018-0479-1}, author = {Rajasekaran, Santhanasabapathy and Thatte, Jayashree and Periasamy, Jayaprakash and Javali, Alok and Jayaram, Manjunath and Sen, Dwaipayan and Krishnagopal, Akshaya and Jayandharan, Giridhara R and Sambasivan, Ramkumar} } @article {1158, title = {Co-expression of Tbx6 and Sox2 identifies a novel transient neuromesoderm progenitor cell state.}, journal = {Development}, volume = {144}, year = {2017}, month = {2017 12 15}, pages = {4522-4529}, abstract = {

Elongation of the body axis is a key aspect of body plan development. Bipotential neuromesoderm progenitors (NMPs) ensure axial growth of embryos by contributing both to the spinal cord and mesoderm. The current model for the mechanism controlling NMP deployment invokes Tbx6, a T-box factor, to drive mesoderm differentiation of NMPs. Here, we identify a new population of Tbx6 cells in a subdomain of the NMP niche in mouse embryos. Based on co-expression of a progenitor marker, Sox2, we identify this population as representing a transient cell state in the mesoderm-fated NMP lineage. Genetic lineage tracing confirms the presence of the NMP cell state. Furthermore, we report a novel aspect of the documented mutant phenotype, namely an increase from two to four ectopic neural tubes, corresponding to the switch in NMP niche, thus highlighting the importance of function in NMP fate decision. This study emphasizes the function of Tbx6 as a bistable switch that turns mesoderm fate {\textquoteright}on{\textquoteright} and progenitor state {\textquoteright}off{\textquoteright}, and thus has implications for the molecular mechanism driving NMP fate choice.

}, keywords = {Animals, Body Patterning, Cell Differentiation, Cell Lineage, Embryonic Stem Cells, Gene Expression Regulation, Developmental, Mesoderm, Mice, Mice, Transgenic, Neural Tube, SOXB1 Transcription Factors, Spinal Cord, Transcription Factors}, issn = {1477-9129}, doi = {10.1242/dev.153262}, author = {Javali, Alok and Misra, Aritra and Leonavicius, Karolis and Acharyya, Debalina and Vyas, Bhakti and Sambasivan, Ramkumar} }