Microarrayed human bone marrow organoids for modeling blood stem cell dynamics

In many leukemia patients, a poor prognosis is attributed either to the development of chemotherapy resistance by leukemic stem cells (LSCs) or to the inefficient engraftment of transplanted hematopoietic stem/progenitor cells (HSPCs) into the bone marrow (BM). Here, we build a 3D in vitro model system of bone marrow organoids (BMOs) that recapitulate several structural and cellular components of native BM. These organoids are formed in a high-throughput manner from the aggregation of endothelial and mesenchymal cells within hydrogel microwells. Accordingly, the mesenchymal compartment shows partial maintenance of its self-renewal and multilineage potential, while endothelial cells self-organize into an interconnected vessel-like network. Intriguingly, such an endothelial compartment enhances the recruitment of HSPCs in a chemokine ligand/receptor-dependent manner, reminiscent of HSPC homing behavior in vivo. Additionally, we also model LSC migration and nesting in BMOs, thus highlighting the potential of this system as a well accessible and scalable preclinical model for candidate drug screening and patient-specific assays

Genes located in Y-chromosomal regions important for male fertility show altered transcript levels in cryptorchidism and respond to curative hormone treatment

Background: Undescended (cryptorchid) testes in patients with defective mini-puberty and low testosterone levels contain gonocytes that fail to differentiate normally, which impairs the development of Ad spermatogonia and ultimately leads to adult infertility. Treatment with the gonadotropin-releasing hormone agonist GnRHa increases luteinizing hormone and testosterone and rescues fertility in the majority of pathological cryptorchid testes. Several Y-chromosomal genes in the male-specific Y region (MSY) are essential for spermatogenesis, testis development and function, and are associated with azoospermia, infertility and cryptorchidism. In this study, we analyzed the expression of MSY genes in testes with Ad spermatogonia (low infertility risk patients) as compared to testes lacking Ad spermatogonia (high infertility risk) before and after curative GnRHa treatment, and in correlation to their location on the Y-chromosome. Results: Twenty genes that are up- or down-regulated in the Ad- group are in the X-degenerate or the ampliconic region, respectively. GnRHa treatment increases mRNA levels of 14 genes in the ampliconic region and decreases mRNA levels of 10 genes in the X-degenerate region. Conclusion: Our findings implicate Y-chromosomal genes, including USP9Y, UTY, TXLNGY, RBMY1B, RBMY1E, RBMY1J and TSPY4, some of which are known to be important for spermatogenesis, in the curative hormonal treatment of cryptorchidism-induced infertility

Comprehensive quantitative characterization of the human term amnion proteome

The loss of fetal membrane (FM) integrity and function at an early time point during pregnancy can have devastating consequences for the fetus and the newborn. However, biomaterials for preventive sealing and healing of FMs are currently non-existing, which can be partly attributed to the current fragmentary knowledge of FM biology. Despite recent advances in proteomics analysis, a robust and comprehensive description of the amnion proteome is currently lacking. Here, by an optimized protein sample preparation and offline fractionation before liquid chromatography coupled to mass spectrometry (LC-MS) analysis, we present a characterization of the healthy human term amnion proteome, which covers more than 40% of the previously reported transcripts in similar RNA sequencing datasets and, with more than 5000 identifications, greatly outnumbers previous reports. Together, beyond providing a basis for the study of compromised and preterm ruptured FMs, this comprehensive human amnion proteome is a stepping-stone for the development of novel healing-inducing biomaterials. The proteomic dataset has been deposited in the ProteomeXchange Consortium with the identifier PXD019410

GnRHa treatment of cryptorchid boys affects genes involved in hormonal control of the HPG axis and fertility.

The gonadotropin-releasing hormone agonist (GnRHa; Buserelin) rescues fertility during adulthood in the majority of high infertility risk cryptorchid boys presenting with defective mini-puberty. However, the molecular events governing this effect are not understood. We report the outcome of an RNA profiling analysis of testicular biopsies from 4 operated patients who were treated with GnRHa for 6 months versus 3 operated controls who were not treated. GnRHa induces a significant transcriptional response, including protein-coding genes involved in pituitary development, the hypothalamic-pituitary-gonadal axis, and testosterone synthesis. Furthermore, we observed an increased abundance of long noncoding RNAs (lncRNAs) participating in epigenetic processes, including AIRN, FENDRR, XIST, and HOTAIR. These data are consistent with the hypothesis that hypogonadotropic hypogonadism in boys with altered mini-puberty is the consequence of a profoundly altered gene expression program involving protein-coding genes and lncRNAs. Our results point to molecular mechanisms that underlie the ability of GnRHa to rescue fertility

Genes involved in long-term memory are expressed in testis of cryptorchid boys and respond to GnRHa treatment

It has been known for many years that boys with unilateral or bilateral undescended testis (cryptorchidism) tend to have a low IQ, and those who belong to the high infertility risk (HIR) group perform less well at school than low infertility risk (LIR) patients. However, the molecular biological processes underlying this phenomenon are not understood. In this study, we report the outcome of testicular RNA profiling for genes involved in long-term memory formation. We analyzed the histology and the transcriptome of testicular biopsies from bilateral HIR cryptorchid boys, comparing those who received GnRHa treatment for 6 months after the first surgery with those who did not receive GnRHa before the second surgery. We found that GnRHa treatment alters the testicular mRNA levels of neuronal genes that are involved in long-term memory and testosterone synthesis. These data highlight a possible molecular link between cryptorchidism, impaired mini-puberty, and diminished cognitive functions. Our results are consistent with the hypothesis that hypogonadotropic hypogonadism in cryptorchid boys with altered mini-puberty may affect neuronal genes important for memory and learning, which could help explaining the negative correlation between cryptorchidism and intellectual abilities

Curative GnRHa treatment has an unexpected repressive effect on Sertoli cell specific genes

Résumé Contexte L’hormone folliculostimulante et la testostérone stimulent les cellules de Sertoli pour soutenir la fonction et la différentiation des cellules germinales. Pendant la minipuberté, lorsque la gonadotrophine (GnRH) stimule les augmentations des taux plasmatiques d’hormone lutéinisante (LH) et de testostérone, les gonocytes sont transformés en spermatogonies Ad. Dans la cryptorchidie, une sécrétion altérée de gonadotrophine lors de la minipuberté entraine une sécrétion insuffisante de LH et de testostérone, une altération de la transition des gonocytes en spermatogonies Ad, et une perturbation de la prolifération des cellules de Sertoli. Un traitement par agoniste de la gonadolibérine (GnRHa/Buserelin) induit une différenciation des gonocytes en spermatogonies Ad et sauvegarde la fertilité. Cette étude a évalué l’impact d’un taux de LH bas sur la fonction des cellules de Sertoli en comparant les données d’expression différentielle de gènes entre des testicules avec LH basse qui sont dépourvus de spermatogonies Ad (Ad-) et des testicules qui ont fini la minipuberté (Ad+). En outre, la réponse au traitement par GnRHa a été analysée par les modifications de la transcription de gènes sélectionnés pour être spécifiques de la cellule de Sertoli. Résultats Les testicules Ad- présentent une expression réduite de 9 des 40 gènes sélectionnés pour être spécifiques de la cellule de Sertoli par comparaison aux testicules Ad+. Le traitement par GnRHa a réprimé l’expression de la plupart des gènes spécifiques de la cellule de Sertoli, y compris les inhibines, mais a augmenté l’expression de gènes qui régulent l’apoptose (FASLG) et la prolifération (GDNF). Conclusions Une minipuberté altérée par des taux diminués de LH et de testostérone affecte le développement des spermatogonies Ad et des cellules de Sertoli par une régulation positive et négative de gènes morphorégulateurs et apoptotiques. Le traitement par GnRHa a un effet inhibiteur sur la plupart des gènes spécifiques de la cellule de Sertoli, ce qui suggère que les cellules de Sertoli subissent un réarrangement cellulaire. Nous proposons que les augmentations gonadotrophine-dépendantes de l’expression de FASLG et de GDNF dirigent la prolifération des cellules de Sertoli et l’auto-renouvèlement des cellules germinales, et qu’elles sont le support de la transition gonocytes vers spermatogonies Ad, indépendante des inhibines

DMRTC2, PAX7, BRACHYURY/T and TERT are implicated in male germ cell development following curative hormone treatment for cryptorchidism-induced infertility

Defective mini-puberty results in insufficient testosterone secretion that impairs the differentiation of gonocytes into dark-type (Ad) spermatogonia. The differentiation of gonocytes into Ad spermatogonia can be induced by administration of the gonadotropin-releasing hormone agonist, GnRHa (Buserelin, INN)). Nothing is known about the mechanism that underlies successful GnRHa treatment in the germ cells. Using RNA-sequencing of testicular biopsies, we recently examined RNA profiles of testes with and without GnRHa treatment. Here, we focused on the expression patterns of known gene markers for gonocytes and spermatogonia, and found that DMRTC2, PAX7, BRACHYURY/T, and TERT were associated with defective mini-puberty and were responsive to GnRHa. These results indicate novel testosterone-dependent genes and provide valuable insight into the transcriptional response to both defective mini-puberty and curative GnRHa treatment, which prevents infertility in man with one or both undescended (cryptorchid) testes

Reduced thrombogenicity of surface-treated Nitinol implants steered by altered protein adsorption

Blood-contacting medical implants made of Nitinol and other titanium alloys, such as neurovascular flow diverters and peripheral stents, have the disadvantage of being highly thrombogenic. This makes the use of systemic (dual) anti-platelet/anticoagulant therapies inevitable with related risks of device thrombosis, bleeding and other complications. Meeting the urgent clinical demand for a less thrombogenic Nitinol surface, we describe here a simple treatment of standard, commercially available Nitinol that renders its surface ultra-hydrophilic and functionalized with phosphate ions. The efficacy of this treatment was assessed by comparing standard and surface-treated Nitinol disks and braids, equivalent to flow diverters. Static and dynamic (Chandler loop) blood incubation tests showed a drastic reduction of thrombus formation on treated devices. Surface chemistry and proteomic analysis indicated a key role of phosphate and calcium ions in steering blood protein adsorption and avoiding coagulation cascade activation and platelet adhesion. A good endothelialization of the surface confirmed the biocompatibility of the treated surface. STATEMENT OF SIGNIFICANCE: Titanium alloys such as Nitinol are biocompatible and show favorable mechanical properties, which led to their widespread use in medical implants. However, in contact with blood their surface triggers the activation of the intrinsic coagulation cascade, which may result in catastrophic thrombotic events. The presented results showed that a phosphate functionalization of the titanium oxide surface suppresses the activation of both coagulation cascade and platelets, avoiding the subsequent formation of a blood clot. This novel approach has therefore a great potential for mitigating the risks associated to either thrombosis or bleeding complications (due to systemic anticoagulation) in patients with cardiovascular implants