LIM homeodomain transcription factors are critical regulators of early development in multiple systems but have yet to be examined for a role in circuit formation. The LIM homeobox gene Lhx2 is expressed in cortical progenitors during development and also in the superficial layers of the neocortex in maturity. However, analysis of Lhx2 function at later stages of cortical development has been hampered by severe phenotypes associated with early loss of function. We identified a particular Cre-recombinase line that acts in the cortical primordium after its specification is complete, permitting an analysis of Lhx2 function in neocortical lamination, regionalization, and circuit formation by selective elimination of Lhx2 in the dorsal telencephalon. We report a profound disruption of cortical neuroanatomical and molecular features upon loss of Lhx2 in the cortex from embryonic day 11.5. A unique feature of cortical circuitry, the somatosensory barrels, is undetectable, and molecular patterning of cortical regions appears disrupted. Surprisingly, thalamocortical afferents innervate the mutant cortex with apparently normal regional specificity. Electrophysiological recordings reveal a loss of responses evoked by stimulation of individual whiskers, but responses to simultaneous stimulation of multiple whiskers were present, suggesting that thalamic afferents are unable to organize the neurocircuitry for barrel formation because of a cortex-specific requirement of Lhx2. We report that Lhx2 is required for the expression of transcription factor paired box gene 6, axon guidance molecule Ephrin A5, and the receptor NMDA receptor 1. These genes may mediate Lhx2 function in the formation of specialized neurocircuitry necessary for neocortical function.
Cytokine production by the endometrial stromal and decidual cells is essential for successful differentiation of the endometrial stromal cells and uterine leukocytes to sustain pregnancy. Interleukin-11 and -15 (IL-11 and IL-15) secreted by the stromal and decidual cells are two key modulators of the process of decidualization and natural killer cell (NK) activity in the uterus and are essential for pregnancy. However, limited information exists on the maternal factors that regulate the production of these cytokines by the stromal cells. In this study, we investigated the role of homeobox A10 (HOXA10) in the regulation of expression of genes encoding the decidualization markers insulin-like growth factor binding protein-1 (IGFBP1), prolactin and the cytokines IL-11 and IL-15 by endometrial stromal and decidual cells in vitro. The results demonstrated that the expression of IGFBP1, Prolactin (PRL), HOXA10, IL11, and IL15 are co-regulated during steroid hormone-mediated decidualization of human endometrial stromal cells in vitro. In the predecidual cells, downregulation of HOXA10 by siRNA suppresses IGFBP1 and IL15, but increases IL11 expression. In the decidualized cells, knocking down HOXA10 inhibits IGFBP1 and PRL expression but elevates the expression of IL11 and IL15. In addition, our data also demonstrate that transient inhibition of HOXA10 expression in the predecidual cells does not influence its ability to subsequently decidualize or affect cytokine expression, suggesting that steroid hormone-mediated decidualization and cytokine production in vitro does not require HOXA10 preconditioning.
Implantation represents the remarkable synchronization between the development of the embryo and the differentiation of the endometrium. It depends on uterine-dependent and embryo-specific events, which are critically and sequentially coordinated. A plethora of molecules have been identified which play major roles before and after embryo implantation. In recent years HomeoboxA10 (HOXA10) has emerged as one of the most promising candidates which regulate the events occurring in the maternal compartment for successful establishment of pregnancy. HOXA10 is a transcription factor that is crucial for development and patterning of the uterus during embryogenesis. In the adult endometrium, HOXA10 is expressed in a menstrual cycle dependent manner and it is regulated by ovarian steroid hormones and embryonic signals, HOXA10 is required for uterine receptivity and implantation, and is a key regulator of decidualization. In the decidua, HOXA10 is involved in regulation of cell cycle and local immunomodulation. The present review summarizes the events that are regulated by HOXA10 in embryo implantation and decidualization.
This study examines the IL-11 mediated activation of downstream signaling and expression of effector molecules to resolve the controversies associated with the IL-11 mediated regulation of the invasiveness of two commonly used trophoblastic cell models viz. JEG-3 and HTR-8/SVneo cells. It has been reported that IL-11 increases the invasiveness of JEG-3 cells while, reduces the invasiveness of HTR-8/SVneo cells. Invasion assay performed simultaneously for both the cell lines confirmed the above findings. In addition, HTR-8/SVneo cells showed a higher basal invasiveness than JEG-3 cells. Western blot showed the IL-11 mediated activation of STAT3(tyr705) and STAT1(tyr701) in both the cell lines. However, IL-11 activated the ERK1/2 phosphorylation in JEG-3 cells but, inhibited it in HTR-8/SVneo cells. Within 10 min of IL-11 treatment, p-STAT3(tyr705) was localized inside the nucleus of both the cell lines but, there was enhanced co-localization of protein inhibitor of activated STAT1/3 (PIAS1/3) and p-STAT3(tyr705) in HTR-8/SVneo cells and not in JEG-3 cells. This could be reason for the poor responsiveness of STAT3 responsive genes like mucin 1 (MUC1) in HTR-8/SVneo cells and not in JEG-3 cells. Further, microarray analysis of the IL-11 treated cells revealed differential responsiveness of JEG-3 as compared to HTR-8/SVneo cells. Several family of genes like activator protein-1 (AP-1) transcription factors (Jun and Fos), mucin-type molecules, MMP23B etc showed enhanced expression in IL-11 treated JEG-3 cells while, there was no response or decrease in their expression in IL-11 treated HTR-8/SVneo cells. Expression of these molecules was confirmed by quantitative RT-PCR. In addition, HTR-8/SVneo cells also showed a significant decrease in the expression of MMP2, MMP3 and MMP9 upon IL-11 treatment. Hence, IL-11 mediated differential activation of signaling and expression of effector molecules is responsible for the differential invasive response of JEG-3 and HTR-8/SVneo cells.
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