Kalidou Ndiaye

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Kalidou Ndiaye, PhD

Assistant professor
Université de Montréal
Départment of Veterinary biomedicine
3200, rue Sicotte, CP. 5000, St-Hyacinthe, Qc, J2S 2M2
This email address is being protected from spambots. You need JavaScript enabled to view it. 
Phone: 450 773-8521 poste 8287                                  
Fax: 450-778-8103

 

Field of research:

The primary field of research in the lab is directed toward the cellular and molecular mechanisms in reproduction with a focus on follicular development in bovine species. A secondary focus is to investigate the functional interactions between reproductive cells and ovarian resident immune cells. We are approaching these projects by using a host of molecular technologies including yeast-two-hybrid screening, RNA interference, plasmid-mediated protein over-expression and promoter-reporter assays to study the expression, mode of action and function of target genes in ovarian follicles and immune cells.

 

 Recent results:

One aspect of our research program aims at identifying and studying the functions of target genes that control the development of ovarian follicles, in relation to follicular dominance and ovulation. We established a gene index for granulosa cells by comparing bovine dominant to ovulatory follicles. We identified target genes that were differentially expressed in dominant follicles as compared to ovulatory follicles following hCG administration. Of interest, we have recently characterized the lysosome-associated protein transmembrane 4 beta (LAPTM4B) in the ovarian follicle and demonstrated its differential expression during follicular development in the cow. Additionally, we have generated specific anti-LAPTM4B polyclonal antibodies and showed that LAPTM4B protein is expressed in granulosa cells of small and dominant follicles but is downregulated by LH/hCG in ovulatory follicles. Projects steming from the granuloma cells-gene index are underway to determine the functions of target genes in the final follicular growth and in ovulation.

In addition to these array studies, we have made significant progress in the field of reproductive immunology showing that there are bidirectional functional effects between immune cells and reproductive tissues. Recent data from our laboratory has led to a new understanding of lymphocyte biology as related to reproductive processes. Notably, we made the discovery that bovine lymphocytes do not express nuclear progesterone receptors, but do express three distinct membrane progesterone receptors (mPRs/PAQRs) along with the progesterone receptor membrane component 1 (PGRMC1). The functional effects of progesterone on lymphocytes are likely mediated by these membrane receptors, in a non-genomic pathway and by acting on the interleukin 2 (IL2) / IL2 receptor system. These effects result in immunosuppressive actions that prevent the activation and proliferation of T lymphocytes in the ovary, thus allowing different reproductive events to successfully take place.

 

Laboratory members:

  • Gabriel Benoit, MSc Student, This email address is being protected from spambots. You need JavaScript enabled to view it. 

 

Publications:

Ndiaye K, Carrière PD, Sirois J, Silversides DW and Lussier JG. (2015). Differential expression of lysosome-associated protein transmembrane-4 beta (LAPTM4B) in granulosa cells of ovarian follicles and in bovine tissues. Journal of Ovarian Research. [In Press].

Poole DH, Ndiaye K, Pate JL. (2013). Expression and regulation of secreted phosphoprotein 1 in the bovine corpus luteum and effects on T lymphocyte chemotaxis. Reproduction (Cambridge, England). 146(6): 527-37.

Ndiaye K, Poole DH, Walusimbi S, Cannon MJ, Toyokawa K, Maalouf SW, Dong J, Thomas P, Pate JL. (2012). Progesterone effects on lymphocytes may be mediated by membrane progesterone receptors. Journal of reproductive immunology. 95(1-2): 15-26.

Ndiaye K, Lussier JG, Pate JL. (2010). Molecular characterization and expression of DERL1 in bovine ovarian follicles and corpora lutea. Reproductive biology and endocrinology : RB&E. 8: 94.

Ndiaye K, Poole DH, Pate JL. (2008). Expression and regulation of functional oxytocin receptors in bovine T lymphocytes. Biology of reproduction. 78(4): 786-93.

Ndiaye K, Fayad T, Silversides DW, Sirois J, Lussier JG. Identification of downregulated messenger RNAs in bovine granulosa cells of dominant follicles following stimulation with human chorionic gonadotropin. Biol Reprod. 2005; 73(2): 324-333. PMID: 15829623.

Lévesque V, Fayad T, Ndiaye K, Nahé Diouf M, Lussier JG. Size-selection of cDNA libraries for the cloning of cDNAs after suppression subtractive hybridization. Biotechniques. 2003; 35(1): 72-78. PMID: 12866408.

 

Other information:

Ndiaye et al., JRI 2012

Immunofluorescence staining of PAQR7 (mPRa) expression on CD4+ T cells. CD4+ sorted T cells were labeled with secondary antibody as a negative control (A and B) or mPRa antibody (C and D) and were visualized in brightfield (B and D) and fluorescence (A and C) using an Olympus BX51 fluorescent microscope at 400x magnification. Immunofluorescent labeling of intact CD4+ T cells with anti-PAQR7 (mPRa) demonstrated punctate cell surface staining, providing support for a membrane- localized progesterone receptor.

cells Kalidou

Ndiaye et al., JRI 2012

The effect of progesterone on calcium influx. (A) Ratio of Fluo-3 (FL1): Fura Red (FL4) fluorescence plotted against time (s) before and after the addition of different concentrations of progesterone (µM, right hand x-axis) or ionomycin (positive control). Arrow indicates time of addition of progesterone or ionomycin. (B) Mean fluorescence intensity of the ratio of Fluo-3:Fura Red from three independent experiments. Asterisks (*) denote differences from the control (p < 0.05). P4: progesterone. Progesterone induced a rapid increase in intracellular calcium in T lymphocytes.

graphics Kalidou