Contiguous follicular lymphoma and follicular lymphoma in situ harboring N-glycosylated sites

International audienceFollicular lymphoma in situ (FLIS) is composed of a clonal B-cell population harboring the typical t(14;18) hallmark of follicular lymphoma (FL), forming unconventional BCL2 Bright CD10 + cell foci in an otherwise normal reactive lymph node (LN). The diagnosis of FLIS is made on the fortuitous discovery of unconventional BCL2 Bright CD10 + cell foci. 1 Several studies recently demonstrated that FLIS are already advanced precursors in follicular lymphomagene-sis, but not necessarily committed to malignant transformation. 2,3 However, the relationship between FLIS and FL still remains unclear, as only a minority (<5%) of FLIS patients eventually develop FL. This is in line with the usually indolent progression of the disease, and the genomic instability observed in FLIS cells, which can engage FL precursor cells either in an evolutionary malignant process, or to an evolutionary dead end. 4 We report the case of a 35-year old male patient who presented with a cervical adenopathy. Histological examination of the excised LN displayed an altered architecture suggestive of FL, consisting of high number of monomorphic large follicles, uniformly spread in the cortical and medullary areas. Most follicles contained a predominant population of small cleaved cells with scant macrophages and mitoses. The mantle zone was reduced or absent. However, in a minor cortical area, a few follicles showed features mimicking residual classical germ cells (GC), including a smaller size, higher cell polymorphism, and a preserved mantle zone (Figure 1A). The BCL2 immunostaining (clone 100) was negative in follicles displaying a typical FL pattern. In contrast, follicles located in the pseudo-residual area were BCL2bright, i.e. more strongly stained than the surrounding mantle zone and reactive T cells (Figure 1B). Most follicles were only slightly positive for Ki67 (Online Supplementary Figure S1A). Both BCL2 – and BCL2 + follicles were CD10 positive (Online Supplementary Figure S1B) and contained a BCL2/JH break-point evidenced by fluorescence in situ hybridization (FISH) (Figure 1C). Taken together these results suggested the diagnosis of simultaneous occurrence of BCL2 – FL (grade I/II) and of BCL2 + FLIS in the same LN. We decided to further analyze those two lesions independently, and performed macrodissection in order to proceed with individual molecular analyses when required. Sanger sequenc-ing revealed that both FLIS and FL shared the same BCL2/JH sequence at the t(14;18)+ breakpoint, and thus originated from the same clone (Figure 1D). We tested two other anti-BCL2 antibodies (E17, SP66) directed against other epitopes, but the staining remained BCL2-in the FL area of the LN, similar to the anti-BCL2 antibody (clone 100) staining (Figure 1E and F). We thus sequenced exons 1 to 3 of the BCL2 gene (B-cell CLL/lym-phoma 2, NG_009361.1). Punctual mutations, resulting in amino acid substitutions, were found in the FL component (Online Supplementary Table S1), and were indeed located in the targeted aa41 to aa54 epitope of clone 100 (mutation

SLY regulates genes involved in chromatin remodeling and interacts with TBL1XR1 during sperm differentiation

Sperm differentiation requires unique transcriptional regulation and chromatin remodeling after meiosis to ensure proper compaction and protection of the paternal genome. Abnormal sperm chromatin remodeling can induce sperm DNA damage, embryo lethality and male infertility, yet, little is known about the factors which regulate this process. Deficiency in Sly, a mouse Y chromosome-encoded gene expressed only in postmeiotic male germ cells, has been shown to result in the deregulation of hundreds of sex chromosome-encoded genes associated with multiple sperm differentiation defects and subsequent male infertility. The underlying mechanism remained, to date, unknown. Here, we show that SLY binds to the promoter of sex chromosome-encoded and autosomal genes highly expressed postmeiotically and involved in chromatin regulation. Specifically, we demonstrate that Sly knockdown directly induces the deregulation of sex chromosome-encoded H2A variants and of the H3K79 methyltransferase DOT1L. The modifications prompted by loss of Sly alter the postmeiotic chromatin structure and ultimately result in abnormal sperm chromatin remodeling with negative consequences on the sperm genome integrity. Altogether our results show that SLY is a regulator of sperm chromatin remodeling. Finally we identified that SMRT/N-CoR repressor complex is involved in gene regulation during sperm differentiation since members of this complex, in particular TBL1XR1, interact with SLY in postmeiotic male germ cells.This work was supported by Inserm (Institut National de la Sante et de la Recherche Medicale), the Agence Nationale de la Recherche program ANR-12–JSV2-0005–01 (to JC), Labex ‘Who am I?’(ANR-11- LABX-0071 under program ANR-11-IDEX-0005-01) and a Marie Curie fellowship FP7-PEOPLE-2010-IEF-273143 (to JC

Peripheral Blood NK Cells from Breast Cancer Patients Are Tumor-Induced Composite Subsets

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Photoperiod is involved in the regulation of seasonal breeding in male water voles ( Arvicola terrestris )

International audienceMammals living at temperate latitudes typically display annual cyclicity in their reproductive activity: births are synchronized when environmental conditions are most favorable. In a majority of these species, day length is the main proximate factor used to anticipate seasonal changes and to adapt physiology. The brain integrates this photoperiodic signal through key hypothalamic structures, which regulate the reproductive axis. In this context, our study aimed to characterize regulations that occur along the hypothalamo–pituitary–gonadal (HPG) axis in male fossorial water voles (Arvicola terrestris, also known as Arvicola amphibius) throughout the year and to further probe the implication of photoperiod in these seasonal regulations. Our monthly field monitoring showed dramatic seasonal changes in the morphology and activity of reproductive organs, as well as in the androgen-dependent lateral scent glands. Moreover, our data uncovered seasonal variations at the hypothalamic level. During the breeding season, kisspeptin expression in the arcuate nucleus (ARC) decreases, while RFRP3 expression in the dorsomedial hypothalamic nucleus (DMH) increases. Our follow-up laboratory study revealed activation of the reproductive axis and confirmed a decrease in kisspeptin expression in males exposed to a long photoperiod (summer condition) compared with those maintained under a short photoperiod (winter condition) that retain all features reminiscent of sexual inhibition. Altogether, our study characterizes neuroendocrine and anatomical markers of seasonal reproductive rhythmicity in male water voles and further suggests that these seasonal changes are strongly impacted by photoperiod

Exposure of rams in sexual rest to sexually activated males in spring increases plasma LH and testosterone concentrations

International audienceABSTRACT Mammals living at temperate latitudes typically display annual cyclicity in their reproductive activity: births are synchronized when environmental conditions are most favorable. In a majority of these species, day length is the main proximate factor used to anticipate seasonal changes and to adapt physiology. The brain integrates this photoperiodic signal through key hypothalamic structures, which regulate the reproductive axis. In this context, our study aimed to characterize regulations that occur along the hypothalamo–pituitary–gonadal (HPG) axis in male fossorial water voles (Arvicola terrestris, also known as Arvicola amphibius) throughout the year and to further probe the implication of photoperiod in these seasonal regulations. Our monthly field monitoring showed dramatic seasonal changes in the morphology and activity of reproductive organs, as well as in the androgen-dependent lateral scent glands. Moreover, our data uncovered seasonal variations at the hypothalamic level. During the breeding season, kisspeptin expression in the arcuate nucleus (ARC) decreases, while RFRP3 expression in the dorsomedial hypothalamic nucleus (DMH) increases. Our follow-up laboratory study revealed activation of the reproductive axis and confirmed a decrease in kisspeptin expression in males exposed to a long photoperiod (summer condition) compared with those maintained under a short photoperiod (winter condition) that retain all features reminiscent of sexual inhibition. Altogether, our study characterizes neuroendocrine and anatomical markers of seasonal reproductive rhythmicity in male water voles and further suggests that these seasonal changes are strongly impacted by photoperiod.</jats:p

Sexual discrimination and attraction through scents in the water vole, Arvicola terrestris

International audienceIn mammals, especially rodents, social behaviours, such as parenting, territoriality or mate attraction, are largely based on olfactory communication through chemosignals. These behaviours are mediated by species-specific chemosignals, including small organic molecules and proteins that are secreted in the urine or in various fluids from exocrine glands. Chemosignal detection is mainly ensured by olfactory neurons in two specific sensory organs, the vomeronasal organ (VNO) and the main olfactory epithelium (MOE). This study aimed to characterise the olfactory communication in the fossorial ecotype of the water voles, Arvicola terrestris. We first measured the olfactory investigation of urine and lateral scent gland secretions from conspecifics. Our results showed that water voles can discriminate the sex of conspecifics based on the smell of urine, and that urinary male odour is attractive for female voles. Then, we demonstrated the ability of the VNO and MOE to detect volatile organic compounds (VOCs) found in water vole secretions using live-cell calcium imaging in dissociated cells. Finally, we evaluated the attractiveness of two mixtures of VOCs from urine or lateral scent glands in the field during a cyclical outbreak of vole populations

Germinal center reentries of BCL2-overexpressing B cells drive follicular lymphoma progression

International audienceIt has recently been demonstrated that memory B cells can reenter and reengage germinal center (GC) reactions, opening the possibility that multi-hit lymphomagenesis gradually occurs throughout life during successive immunological challenges. Here, we investigated this scenario in follicular lymphoma (FL), an indolent GC-derived malignancy. We developed a mouse model that recapitulates the FL hallmark t(14;18) translocation, which results in constitutive activation of antiapoptotic protein B cell lymphoma 2 (BCL2) in a subset of B cells, and applied a combination of molecular and immunofluorescence approaches to track normal and t(14;18)(+) memory B cells in human and BCL2-overexpressing B cells in murine lymphoid tissues. BCL2-overexpressing B cells required multiple GC transits before acquiring FL-associated developmental arrest and presenting as GC B cells with constitutive activation-induced cytidine deaminase (AID) mutator activity. Moreover, multiple reentries into the GC were necessary for the progression to advanced precursor stages of FL. Together, our results demonstrate that protracted subversion of immune dynamics contributes to early dissemination and progression of t(14;18)(+) precursors and shapes the systemic presentation of FL patients

SLY regulates genes involved in chromatin remodeling and interacts with TBL1XR1 during sperm differentiation

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