Iva Arato

Mesenchymal Stem Cells Reduce Colitis in Mice via Release of TSG6, Independently of Their Localization to the Intestine

BACKGROUND & AIMS Mesenchymal stem cells (MSCs) are pluripotent cells that can promote expansion of immune regulatory cells and might be developed for the treatment of immune disorders, including inflammatory bowel diseases. MSCs were reported to reduce colitis in mice; we investigated whether MSC localization to the intestine and production of paracrine factors, including tumor necrosis factor-induced protein 6 (TSG6), were required for these effects. METHODS MSCs were isolated from bone marrow (BM-MSCs) of 4- to 6-week-old C57BL/6, C57BL/6-green fluorescent protein, or Balb/c Tsg6-/- male mice. Colitis was induced by ad libitum administration of dextran sulfate sodium for 10 days; after 5 days the mice were given intraperitoneal injections of BM-MSCs or saline (controls). Blood samples and intestinal tissues were collected 24, 48, 96, and 120 hours later; histologic and flow cytometry analyses were performed. RESULTS Injection of BM-MSCs reduced colitis in mice, increasing body weight and reducing markers of intestinal inflammation, compared with control mice. However, fewer than 1% of MSCs reached the inflamed colon. Most of the BM-MSCs formed aggregates in the peritoneal cavity. The aggregates contained macrophages and B and T cells, and produced immune-regulatory molecules including FOXP3, interleukin (IL)10, transforming growth factor-β, arginase type II, chemokine (C-C motif) ligand 22 (CCL22), heme oxygenase-1, and TSG6. Serum from mice given BM-MSCs, compared with mice given saline, had increased levels of TSG6. Injection of TSG6 reduced the severity of colitis in mice, along with the numbers of CD45+ cells, neutrophils and metalloproteinase activity in the mucosa, while increasing the percentage of Foxp3CD45+ cells. TSG6 injection also promoted the expansion of regulatory macrophages that expressed IL10 and inducible nitric oxide synthase, and reduced serum levels of interferon-γ, IL6, and tumor necrosis factor. Tsg6-/- MSCs did not suppress the mucosal inflammatory response in mice with colitis. CONCLUSIONS BM-MSCs injected into mice with colitis do not localize to the intestine but instead form aggregates in the peritoneum where they produce immunoregulatory molecules, including TSG6, that reduce intestinal inflammation. TSG6 is sufficient to reduce intestinal inflammation in mice with colitis.

Encapsulated mesenchymal stem cells for in vivo immunomodulation

Acute myeloid leukemia with biallelic CEBPA gene mutations and normal karyotype represents a distinct genetic entity associated with a favorable clinical outcome. J Clin Oncol 2010; 28: 570–577. 11 Döhner K, Tobis K, Ulrich R, Fröhling S, Benner A, Schlenk RF et al. Prognostic significance of partial tandem duplications of the MLL gene in adult patients 16 to 60 years old with acute myeloid leukemia and normal cytogenetics: a study of the Acute Myeloid Leukemia Study Group Ulm. J Clin Oncol 2002; 20: 3254–3261. 12 Schlenk RF, Döhner K, Krauter J, Fröhling S, Corbacioglu A, Bullinger L et al. Mutations and treatment outcome in cytogenetically normal acute myeloid leukemia. N Engl J Med 2008; 358: 1909–1918. 13 Haferlach C, Mecucci C, Schnittger S, Kohlmann A, Mancini M, Cuneo A et al. AML with mutated NPM1 carrying a normal or aberrant karyotype show overlapping biologic, pathologic, immunophenotypic, and prognostic features. Blood 2009; 114: 3024–3032. 14 Grossmann V, Schnittger S, Schindela S, Klein HU, Eder C, Dugas M et al. Strategy for robust detection of insertions, deletions, and point mutations in CEBPA, a GC-rich content gene, using 454 next-generation deep-sequencing technology. J Mol Diagn 2011; 13: 129–136. 15 Schnittger S, Alpermann T, Eder C, Schindela S, Grossmann V, Kern W et al. The role of different genetic subtypes in CEBPA mutated AML. Blood (ASH Ann Meet) 2010; 116: 752 (Abstracts: oral presentation).

Prolongation of skin allograft survival in rats by the transplantation of microencapsulated xenogeneic neonatal porcine Sertoli cells.

Skin rejection remains a major hurdle in skin reconstructive transplantation surgery. In fact, 85% of the grafted patients experience at least one episode of acute skin rejection in the first year. It has been observed that Sertoli cells (SC), when co-transplanted with allo- or xenogeneic cell/tissues, can induce graft acceptance in the absence of systemic immunosuppression. A method aimed at significantly prolonging skin allografts in rats transplanted with barium alginate-based microencapsulated xenogeneic porcine SC (SC-MCs) is described. Results demonstrated that intraperitoneal (IP) transplantation of SC-MCs with high cellular viability and function can significantly prolong allogeneic skin grafts when compared to transplantation controls receiving only empty alginate capsules (E-MCs). Lymphocytic infiltration at the skin graft site was not observed in 80% of the SC-MCs transplanted rats and these recipient animals showed a significant increased expression of T regulatory (Tregs) cells when compared to E-MCs transplantation controls. The findings of this report further substantiate the positive therapeutic effects of SC on transplantation technology mediated by Sertoli cell-induced alterations of the hosts immune system and indicate new perspectives and new strategies for successful skin tissue allografts.

Reversal of experimental Laron Syndrome by xenotransplantation of microencapsulated porcine Sertoli cells.

Recombinant human IGF-1 currently represents the only available treatment option for the Laron Syndrome, a rare human disorder caused by defects in the gene encoding growth hormone receptor, resulting in irreversibly retarded growth. Unfortunately, this treatment therapy, poorly impacts longitudinal growth (13% in females and 19% in males), while burdening the patients with severe side effects, including hypoglycemia, in association with the unfair chore of taking multiple daily injections that cause local intense pain. In this study, we have demonstrated that a single intraperitoneal graft of microencapsulated pig Sertoli cells, producing pig insulin-like growth factor-1, successfully promoted significant proportional growth in the Laron mouse, a unique animal model of the human Laron Syndrome. These findings indicate a novel, simply, safe and successful method for the cell therapy-based cure of the Laron Syndrome, potentially applicable to humans.

Long-term stability, functional competence, and safety of microencapsulated specific pathogen-free neonatal porcine Sertoli cells: a potential product for cell transplant therapy

Porcine Sertoli cells (pSCs) have been employed for cell therapy in pre‐clinical studies for several chronic/immune diseases as they deliver molecules associated with trophic and anti‐inflammatory effects. To be employed for human xenografts, pSCs products need to comply with safety and stability. To fulfill such requirements, we employed a microencapsulation technology to increase pre‐transplant storage stability of specific pathogen‐free pSCs (SPF‐pSCs) and evaluated the in vivo long‐term viability and safety of grafts.

Xenograft of Microencapsulated Sertoli Cells Reverses T1DM in NOD Mice by Inducing Neogenesis of Beta-Cells

Background. Sertoli cells (SCs) provide an immunoprotective environment to pancreatic islet grafts for treatment of insulin-dependent diabetes. Aim of this work was to verify whether intraperitoneal graft of SCs, enveloped in barium alginate-based microcapsules, would reverse overt spontaneous diabetes in nonobese diabetic (NOD) mice by eliciting generation of newly formed functional islets &bgr;-cells. Methods. Microcapsules were prepared, according to our method, by a mono air-jet device system and thereafter examined as far as (a) SC morphology by light microscopy; (b) SC viability by fluorescence microscopy; (c) SC in vitro function; and (d) SC in vivo function, as quoted by diabetes reversal in the NOD mice, were concerned. Results. SCs containing microcapsules exhibited excellent morphology, viability, and function, and when grafted into the NODs, they induced stable reversion of the disease in 81% of the cases. The treated mice showed dramatic increase in regulatory T lymphocytes (Treg) when compared with control diabetic NODs treated with empty capsules only. Histologic examination of pancreata retrieved from the SC-transplanted animals showed total disappearance of insulitis, with appearance of new islets, as shown by immunocytochemistry; restored ability of the islets to produce insulin, glucagon, and somatostatin; and finally, increased expression of key transcriptional factors such as neurogenin 3. Conclusions. SCs, enveloped in barium alginate-based microcapsules, showed no long-term loss of their functional and morphological properties in vitro or in vivo. Xenograft of microencapsulated-SC–induced reversal of spontaneous diabetes in the majority of the treated NOD mice, based on SC-related powerful immunomodulatory and pro-&bgr;-cell regeneration properties.

In vitro cadmium effects on ECM gene expression in human bronchial epithelial cells.

Occupational and environmental exposure to the heavy metal cadmium (Cd) and its inhalation from cigarette smoke are associated with emphysema. Many growth factors and extracellular matrix (ECM) cell signaling molecules are directly involved in the epithelial bronchial cell pathway. This study investigated the direct effects of Cd on the production of several ECM components in human bronchial epithelial cells (BEAS-2B) that were exposed in vitro for 48 h to sub-toxic and toxic concentrations of Cd. Gene expression of collagens, metalloproteases (MMPs), integrins, tenascin and vitronectin were quantified by RT-PCR. To study apoptosis cascade, annexin assay and cellular cytotoxicity by MTT assay were performed. We also investigated whether an imbalance in the TGFβ/TGFβ receptor (TGFβR) expression mediated Cd effects. The results showed the sub-toxic Cd dose significantly increased tenascin, vitronectin, β1 and β5 integrin gene expression. The toxic Cd dose decreased type IV and V collagen, α1, α2 and β3 integrins. Both Cd doses down-regulated type I collagen and up-regulated metalloproteases. Each Cd dose caused a different imbalance in the complex pattern of TGFβ and its receptors. No alteration in classic apoptotic marker protein expression was observed in presence of the sub-toxic dose of Cd, suggesting this metal alters ECM production without apoptotic activation. In conclusion, all these data show even sub-toxic Cd dose exposure alters the specific gene expression of several ECM components that are crucially implicated in the mechanical properties of lung parenchyma supporting the hypothesis that the mechanism underlying Cd-induced lung disease may involve downstream changes in TGFβ/TGFβR signaling.

Intraperitoneal injection of microencapsulated Sertoli cells restores muscle morphology and performance in dystrophic mice.

Duchenne muscular dystrophy (DMD) is a genetic disease characterized by progressive muscle degeneration leading to impaired locomotion, respiratory failure and premature death. In DMD patients, inflammatory events secondary to dystrophin mutation play a major role in the progression of the pathology. Sertoli cells (SeC) have been largely used to protect xenogeneic engraftments or induce trophic effects thanks to their ability to secrete trophic, antiinflammatory, and immunomodulatory factors. Here we have purified SeC from specific pathogen-free (SPF)-certified neonatal pigs, and embedded them into clinical grade alginate microcapsules. We show that a single intraperitoneal injection of microencapsulated SPF SeC (SeC-MC) in an experimental model of DMD can rescue muscle morphology and performance in the absence of pharmacologic immunosuppressive treatments. Once i.p. injected, SeC-MC act as a drug delivery system that modulates the inflammatory response in muscle tissue, and upregulates the expression of the dystrophin paralogue, utrophin in muscles through systemic release of heregulin-β1, thus promoting sarcolemma stability. Analyses performed five months after single injection show high biocompatibility and long-term efficacy of SeC-MC. Our results might open new avenues for the treatment of patients with DMD and related diseases.

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.

Xenograft of microencapsulated Sertoli cells for the cell therapy of type 2 diabetes mellitus in spontaneously diabetic nonhuman primates: preliminary data.

Insulin resistance in type 2 diabetes mellitus (T2DM) may be due to a chronic inflammation of the visceral adipose tissue (VAT) leading to local and systemic increases in proinflammatory cytokines. Microencapsulated porcine Sertoli cells (MC-pSC), by provision of immunomodulatory and trophic factors, have been successfully used to reduce such inflammation in rodent animal models of type 1 diabetes with no complications or deleterious side effects. Herein, we have begun to investigate this novel and safe therapeutic approach in the spontaneously obese nonhuman primate with spontaneous, insulin-dependent T2DM. After MC-pSC intraperitoneal injection we have evaluated, throughout a 6-month follow-up period, daily ad libitum fed glucose levels, daily exogenous insulin supplementation, biweekly body weight measurements, periodic fasting blood glucose concentrations, glycated hemoglobin (HbA1c) levels, glucose tolerance tests (GTT), and fluorescence-activated cell sorting cytometry (FACS) assessment of peripheral blood mononuclear cells. Very preliminarily, we have observed a slight reduction in fasting (FPG) and mean nonfasting (NF) plasma glucose levels. We found minimal changes, only in 1 animal, in daily exogenous insulin requirements and HbA1c levels. Flow cytometric analysis was associated with decrease in CD8(+) cells only in 1 recipient with a reduction in mean regulatory T Cells (Treg), whereas interestingly, decrease of B lymphocytes was observed in both animals. These results may suggest that this novel MC-SC-based transplantation protocol might possibly impact the metabolic status of T2DM in higher mammals that are close to humans.