45 research outputs found
IDO Mediates TLR9-Driven Protection from Experimental Autoimmune Diabetes
Abstract
Originally predicated on the recognition of an increasing prevalence of allergy, the hygiene hypothesis was later found to accommodate the contrasting epidemiologic trends in developed countries for infectious vs autoimmune diseases. Experimentally, reduced exposure to infections will increase the risk of disease in several models of experimental autoimmunity. Although TLRs were initially considered as stimulatory molecules capable of activating early defense mechanisms against invading pathogens, emerging data suggest that they can also exert a regulatory function. In the present study, we evaluated whether TLR3 and TLR9, recognizing microbial dsDNA and CpG-containing DNA sequences, respectively, play a role in the protection from experimental autoimmune diabetes induced in C57BL/6 mice by streptozotocin. In wild-type animals, the disease was accompanied by up-regulation of IDO in pancreatic lymph nodes and would be greatly exacerbated by in vivo administration of an IDO inhibitor. Conversely, administration of a CpG-containing oligodeoxynucleotide greatly attenuated the disease in an IDO-dependent fashion. TLR9-, but not TLR3-deficient mice developed a more robust disease, an event accompanied by lack of IDO induction in pancreatic lymph nodes. Thus, our data suggest that the TLR9-IDO axis may represent a valuable target in the prevention/therapy of type 1 diabetes
Acceleration of Functional Maturation and Differentiation of Neonatal Porcine Islet Cell Monolayers Shortly In Vitro Cocultured with Microencapsulated Sertoli Cells
The limited availability of cadaveric human donor pancreata as well as the incomplete success of the Edmonton protocol for human islet allografts fasten search for new sources of insulin the producing cells for substitution cell therapy of insulin-dependent diabetes mellitus (T1DM). Starting from isolated neonatal porcine pancreatic islets (NPIs), we have obtained cell monolayers that were exposed to microencapsulated monolayered Sertoli cells (ESCs) for different time periods (7, 14, 21 days). To assess the development of the cocultured cell monolayers, we have studied either endocrine cell phenotype differentiation markers or c-kit, a hematopoietic stem cell marker, has recently been involved with growth and differentiation of β-cell subpopulations in human as well as rodent animal models. ESC which were found to either accelerate maturation and differentiation of the NPIs β-cell phenotype or identify an islet cell subpopulation that was marked positively for c-kit. The insulin/c-kit positive cells might represent a new, still unknown functionally immature β-cell like element in the porcine pancreas. Acceleration of maturation and differentiation of our NPI cell monolayers might generate a potential new opportunity to develop insulin-producing cells that may suite experimental trials for cell therapy of T1DM
An ultrastructural study of Sertoli cells inside alginate microcapsules
Sertoli cells (SeC) are the main components of the blood-testis barrier, are essential for spermatogenesis and are long known for their ability to secrete trophic, anti-inflammatory and immunomodulatory factors [1]. For these reasons, SeC have been encapsulated in sodium alginate microcapsules and then used to create an ectopic immune-privileged environment to prolong survival of co-transplanted cells or modulate the immune responses [2]. Encapsulation has represented an improvement for the use of SeC. In fact, it has been reported that inside the microcapsules SeC (SeC-MC) act as a “micro-biofactory” and drug delivery system. By secreting immunomodulatory and trophic factors once injected into the peritoneal cavity of dystrophic mice [3], they can ameliorate muscle morphology and function. Since the manipulation of the microcapsules is rather complicated, we performed for the first time, an ultrastructure study on SeC-MC. The good cell morphology, along with viability of organellar compartment, was demonstrated
A new model to study the effects of gonadotropins on an “in vitro” prepubertal artificial porcine mini-testis
At present, there is no reliable experimental model “in vitro” to analyze the complex interactions between gonadotropins on the pre-pubertal Sertoli cells (SC) and Leydig cells (LD). Considering that, in the pre-pubertal period, only the anti-mullerian hormone (AMH) is upregulated by FSH and down-regulated by androgens [1-2], AMH could be considered a potential marker of pre-pubertal testis function. The aim of our work was to study the effects of FSH, LH and HCG on an in-vitro model of “mini-testis”. SC and LD, obtained from 15-20 days old neonatal pigs, were isolated and evaluated in terms of purity by AMH (unique pre-pubertal SCs marker), INSL3 (LD marker), ASMI (peritubular cells marker) and PGP9.5 (gonocytes and spermatogonial cells marker). Finally, purified SC and LD were co-cultured to obtain the “mini-testis” and were stimulated with gonadotropins. We have then evaluated: a) AMH, inhibin B and testosterone levels released in the culture medium (by ELISA), both in basal conditions and after stimulations; b) analysis of the follicle-stimulating hormone receptor (FSHR), MAPkinasi (Erk1/2, AKT) by Real Time PCR. We show an increase in inhibin B levels after FSH and FSH/LH stimulation and a selectively increase in testosterone production after LH treatment. AMH secretion was downregulated by FSH treatment. These data seem to preliminarily suggest that ERK1/ ERK2 expression was up-regulated by FSH and FSH/LH stimulation while FSHreceptor expression was down-regulated by FSH and increased by FSH/LH treatment; AKT was up-regulated in all conditions. The proposed model, by creating an artificial mini- testis, could help better understanding the complex and still partially unknown interactions between human gonadotropins, SC and LD possibly creating a novel background to shed light inside a future therapy of male infertilit
Transplantation of microencapsulated Sertoli cells in a mouse model of Duchenne muscular dystrophy (DMD) reduces inflammation and rescues muscle performance
Duchenne muscular dystrophy (DMD), a progressive muscle degenerative disease associated with chronic inflammation, necrosis and fibrosis, is currently treated with antiinflammatory steroids, despite their limited efficacy and undesired side effects. Testicular Sertoli cells (SCs) have been successfully implanted to treat many experimental diseases due to their ability to secrete trophic, antiinflammatory and immunomodulatory molecules (Mital et al., 2010). We transplanted microencapsulated SCs, within highly biocompatible microcapsules (Luca et al., 2007) into the peritoneal cavity of mdx mice, an animal model of DMD. Three weeks after transplantation, skeletal muscles from SC-treated mice, compared with muscles from mock-treated mice, showed: i) dramatically reduced number of infiltrated cells, including (MAC3+) macrophages; ii) a marked decrease in necrotic myofibers, and an increased number of regenerated (normally sized and centrally nucleated) myofibers; and, iii) a significant decrease in fibrous tissue infiltration. Moreover, SC-treated, but not mock-treated mdx mice showed recovery of muscle performance in treadmill endurance tests and a comparable resistance to exercise-induced muscle damage to that of untreated wildtype mice. These preliminary results suggest that our transplant product creates a suitable microenvironment for muscle regeneration and growth potentially applicable to DMD patients
Effects of cadmium on viability and function of porcine pre-pubertal Sertoli cells
Cadmium, an ubiquitous environmental pollutant mainly used for industrial purposes, is highly associated with reproductive toxicity. Sertoli cells (SC), by providing an appropriate microenvironment for the development of germ cells, play a pivotal role on spermatogenesis regulation (Geoffroy-Siraudin et al. 2012). Aim of our investigation was to assess the effects of cadmium on high mammalian SC viability and function. Porcine pre-pubertal SC were isolated, according to previously established methods (Fallarino et al. 2009) and treated with 3 different concentrations (5-10-15 μM) of cadmium chloride. The evaluation of SC function in terms of inhibin B and anti-Müllerian hormone (AMH) secretion showed a significant decrease in all SC treated conditions respect as compared to SC control. On the contrary, evaluation of the FSH-R integrity on SC surface, in terms of 17-b-estradiol production under FSH stimulation, showed no difference between SC control and 5 μM cadmium treated SC monolayers in comparison to 10 and 15μM cadmium treated SC monolayers, where FSH-R was impaired. In addition, the apoptotic test showed a significant increase of early (ANNEXIN V-/Propidium Iodide+) (AV-/PI+) and late apoptotic cells (AV+/ PI+) in all cadmium treated SC conditions in comparison with SC control. In conclusion, our data demonstrate that cadmium, even at low dose, exerts toxic effects on Sertoli cells function possibly adversely affecting the spermatogenesis
Pb effects on an experimental model of porcine prepubertal Sertoli cells
The environmental pollution is one of the main factors implicated in the world’s fertility decline. Lead (Pb) is one of the major heavy metal contaminants that impairs several organs but preferentially accumulates in male reproductive organs and alters in vivo and in vitro sperm quality [1]. Nowadays, the underlying mechanisms remain unclear. Sertoli cells (SC) provides structural and metabolic support to the spermatogenic cells within the seminiferous tubules, therefore, metabolic and structural changes in SC affect the developing germ cells and consequently alter spermatogenesis. This study aimed to assess whether exposure to subtoxic doses of Pb would adversely affect superior mammalian SC function. Highly purified and functional porcine pre-pubertal SC were isolated [2] and treated with three different Pb acetate concentrations. Parameters of SC functionality, such as inhibin B and anti-Müllerian hormone (AMH) mRNAs and proteins were decreased by Pb exposure respect to the control, such as the FSH-r integrity in terms of 17-β-estradiol production, under FSH stimulation. In addition, we observed an increase of AKT and mTOR mRNAs, p38 phosphorylation ratio and Akt phosphorylation ratio in all experimental conditions, respect to the control. In conclusion, the Pb-related toxicity on SC, even at low concentrations, is expected to alter spermatogenesis
Isolation and characterization of extracellular vesicles secreted by pre-pubertal Sertoli cells
Recent studies have shown that extracellular vesicles (Ev) are an important mechanism of intercellular communication. In fact, Ev may contain proteins, DNA and mRNA. In particular, the latter play an important role in various biological processes including regulation and cell differentiation [1]. Sertoli cells (SC), previously considered as a mere “sustentacular cell”, were re-evalued in their functions and elevated to the rank of a “sentinel” in spermatogenesis due to production of trophic, differentiation and immune-modulators factors. Porcine pre-pubertal SC, isolated by our method [2], upon 48 hours culture, SC were stimulated with recombinant a-follitropin (rFSH) or FSH + testosterone (T) to evaluate both the presence in the medium of SC-derived Ev (SC-Ev) and SC-Ev content, in terms of mRNA for Anti-Müllerian hormone (AMH), inhibin B, Androgen Binding Protein (ABP) and FSH-receptor (FSH-r), by RT-PCR. SEM analysis highlighted the presence of SC-Nv in culture medium with mean diameters < 149 nm. We have also demonstrated, within the SC-Ev, significant increase in mRNA for AMH, ABP and FSH-r after both FSH and FSH+T stimulation, as compared to unstimulated SC-Ev. Differently from unstimulated SC-Ev, mRNA inhibin B levels were unchanged in FSH-stimulated SC-Ev, and increased after FSH+T stimulation. Interestingly, an opposite trend was shown in mRNA secretion, in control SC monolayer where, we demonstrated a decrease of AMH and FSH-r mRNA (after both stimulations with FSH or FSH + T) and an increase of inhibin B mRNA. On the contrary, mRNA ABP levels, in SC monolayer, decreased after stimulation with FSH but were unchanged in the presence of FSH+T. For the first time in the Literature, our work has shown the presence of SC-Nv containing AMH, inhibin B, ABP and FSH-r mRNA regulated by FSH with or without T. This result may suggest that other testicular cells could produce factors that, until now, were considered an exclusive SC secretory product.This work was supported by Mr.Gary Harlem (Altucell Inc. 3 Astor Court, Dix Hills, New York, NY) and Merck-Serono (London, UK)
Xenograft of free or microencapsulated Sertoli cells as a potential therapy for experimental Type 2 Diabetes Mellitus
Introduction and Aim. Type 2 Diabetes Mellitus (T2DM), one of the world’s most important, common and costly diseases associated with devastating complications, is caused by insulin resistance mainly due to a chronic inflammation of the visceral adipose tissue with local and systemic increases in proinflammatory cytokines and adipokines such as tumor necrosis factor-α (TNF-α) and IL-6. Sertoli cells (SC), considered mere mechanical cell aids, have been recently revisited with respect to their functional competence showing that these cells may provide immunomodulatory and trophic factors that are able to ameliorate survival and development of different cell types and constitute an immuno-protective shield for transplantation in many diseases such as Type 1 Diabetes Mellitus. Aim of this work was to verify if the injection of free (subcutaneously) or microencapsulated (intraperitoneally) SC would reverse hyperglycaemia in db/db mice spontaneous T2DM Materials and Methods. Porcine pre-pubertal SC were isolated, according to previously established methods, after finely chopping the retrieval testicles, with double enzymatic digestion with Collagenase P and a mixed solution of trypsin and DNase I. SC enveloped in Barium alginate-based microcapsules (Ba-SCMCs) were prepared according to our method, by a mono air-jet device system. Free SC and Ba-SCMCs were examined as far as: (a) SC morphology by light microscopy; (b) SC viability, by fluorescence microscopy after staining with ethidium bromide and fluorescein diacetate; (c) SC in vitro function (α-aromatase activity and IGF-I secretion); (d) reversal of T2DM in spontaneous diabetes db/db mice, were concerned. Results. Ba-SCMCs showed excellent features in terms of size, morphology, sphericity and coalescence. SC viability, both in free and microencapsulated SC, was very high (over 90%). Very good α-aromatase activity and IGF-I secretion were associated with the examined SC preparations. Both subcutaneous free SC injection and intraperitoneal transplantation of Ba-SCMCs demonstrated a significant reduction, in 60% of the treated mice, of HbA1c (6.6 % vs 8.8 %) with a normalization of intraperitoneal glucose tolerance test. Conclusions. SC may be enveloped in Ba-SCMCs with no loss of their functional properties and morphology. Xenograft of SC, both free and enveloped in barium alginate microcapsules, induced an important reduction of HbA1c blood levels with a normalization of glucose tolerance test (IPGTT). This result might open new perspectives for the future therapy of human T2DM