Thyroid hormones and obesity: a known but poorly understood relationship.

Hormony tarczycy (thyroid hormones, TH) sa zaangazowane w wiele róznych procesów biologicznych, wliczajac rozwój ukladu nerwowego, regulacje metabolizmu posredniego oraz zuzycie energii. Aktywnie uczestnicza w podstawowym zuzyciu energii i termogenezie adaptacyjnej i z tego wzgledu moga miec wplyw na mase ciala w przebiegu chorób tarczycy. Otylosc to niezakazna, przewlekla, zapalna choroba metaboliczna, która implikuje dodatni bilans energetyczny. Tkanka tluszczowa produkuje szereg hormonów i adipocytokin, takich jak leptyna, które moga wplywac na stan tarczycy na róznych poziomach. Istnieja dowody na to, ze dysfunkcja tarczycy moze predysponowac do otylosci i odwrotnie, istnieja dowody sugerujace, ze otylosc powoduje zmiany dotyczace tarczycy. Celem tej pracy bylo opisanie zwiazku miedzy ukladem tarczycy a otyloscia. Ponadto w pracy zaprezentowano hipotetyczny model podkreslajacy znaczenie obwodowej dejodynacji hormonów tarczycy i jego role w ustanowieniu dodatniego bilansu energetycznego. Podsumowujac, mozemy stwierdzic, ze relacja miedzy ukladem tarczycy a otyloscia i nadwaga jest zlozona i obejmuje wiele poziomów interakcji. Ponadto, poddajac ocenie otylego pacjenta, powinno sie rozwazyc ocene funkcji tarczycy, aby uzyskac lepsze i spersonalizowane efekty leczenia.

Signals from the caudal diencephalon are required for the projection of the Interstitial Nuclei of Cajal.

Axonal projection is controlled by discrete regions localized at the neuroepithelium, guiding the neurite growth during embryonic development. These regions exert their effect through the expression of a family of chemotropic molecules, which actively participate in the formation of neuronal connections of the central nervous system in vertebrates. Previous studies describe prosomere 1 (P1) as a possible organizer of axonal growth of the rostral rhombencephalon, contributing to the caudal projection of reticulospinal rhombencephalic neurons. This work studies the contribution of chemotropic signals from P1 or pretectal medial longitudinal fascicle (MLF) neurons upon the caudal projection of the interstitial nuclei of Cajal (INC). By using in ovo surgeries, retrograde axonal labeling, and immunohistochemical techniques, we were able to determine that the absence of P1 generates a failure in the INC caudal projection, while drastically diminishing the reticulospinal rhombencephalic neurons projections. The lack of INC projection significantly decreases the number of reticulospinal neurons projecting to the MLF. We found a 48.6% decrease in the projections to the MLF from the rostral and bulbar areas. Similarly, the observed decrease at prosomere 2 was 51.5%, with 61.8% and 32.4% for prosomeres 3 and 4, respectively; thus, constituting the most affected rostral regions. These results suggest the following possibilities: i, that the axons of the reticulospinal neurons employ the INC projection as a scaffold, fasciculating with this pioneer projection; and ii, that the P1 region, including pretectal MLF neurons, exerts a chemotropic effect upon the INC caudal projection. Nonetheless the identification of these chemotropic signals is still a pending task.

The transcription factors Sox5 and Sox9 regulate Catsper1 gene expression.

Catsper is a Ca(2+)permeable channel required for sperm hyperactivation. In spite of its central role in male fertility, the transcriptional mechanisms that regulate Catsper1 expression are ill defined. In this work, we describe the identification and characterization of important regulatory elements in the murine Catsper1 gene proximal promoter. Four transcription start sites and three functional Sox-binding sites were identified in the Catsper1 promoter. Interestingly, transcription factors Sox5 and Sox9 caused a significant increase in transactivation of the Catsper1 promoter in heterologous systems, and chromatin immunoprecipitation assays showed that both transcription factors interact with the Catsper1 promoter in vivo. These results provide new insights into the molecular mechanisms that control Catsper channel expression.

Measuring intracellular Ca2+ changes in human sperm using four techniques: conventional fluorometry, stopped flow fluorometry, flow cytometry and single cell imaging.

Spermatozoa are male reproductive cells especially designed to reach, recognize and fuse with the egg. To perform these tasks, sperm cells must be prepared to face a constantly changing environment and to overcome several physical barriers. Being in essence transcriptionally and translationally silent, these motile cells rely profoundly on diverse signaling mechanisms to orient themselves and swim in a directed fashion, and to contend with challenging environmental conditions during their journey to find the egg. In particular, Ca(2+)-mediated signaling is pivotal for several sperm functions: activation of motility, capacitation (a complex process that prepares sperm for the acrosome reaction) and the acrosome reaction (an exocytotic event that allows sperm-egg fusion). The use of fluorescent dyes to track intracellular fluctuations of this ion is of remarkable importance due to their ease of application, sensitivity, and versatility of detection. Using one single dye-loading protocol we utilize four different fluorometric techniques to monitor sperm Ca(2+) dynamics. Each technique provides distinct information that enables spatial and/or temporal resolution, generating data both at single cell and cell population levels.

Are TRP channels involved in sperm development and function?

Spermatozoa must translate information from their environment and the egg to achieve fertilization in sexually reproducing animals. These tasks require decoding a variety of signals in the form of intracellular Ca(2+) changes. As TRP channels constitute a large family of versatile multi-signal transducers, they are interesting subjects in which to explore their possible participation in sperm function. Here, we review the evidence for their presence and involvement in sperm motility, maturation, and the acrosome reaction, an exocytotic process required for sperm-egg fusion. Since store-operated Ca(2+) entry (SOCE) has been proposed to play an important role in these three functions, the main proteins responsible for this transport (STIM and ORAI) and their interaction with TRPs are also discussed. Improving our tools to solve infertility, improve animal breeding, and preserve biodiversity requires a better understanding of how Ca(2+) is regulated in spermatozoa.