Hydrogen Sulfide (H2S) Based Therapeutics for Bone Diseases: Translating Physiology to Treatments

Much progress has been made in the past decade in elucidating the physiological, pathophysiological and pharmacological role of Hydrogen Sulphide (H2S). Recently a function of H2S virtually in every tissue of the human organism has emerged. However, the H2S-mediated regulation of bone homeostasis has been scarcely investigated. Despite a recent increased interest in the field, many fundamental issues remain indeterminate. The main objective of this study was to increase the basic knowledge on the role of H2S in bone through in vitro and in vivo studies and develop novel therapeutic strategies for bone diseases. Ex vivo experiments revealed that H2S-generating enzymes (Cystathionine-β-synthase, CBS; Cystathionine-γ-lyase, CSE) are expressed in human bone tissues and human bone-derived cells. In vitro experiments evidenced that CBS and CSE expression is a distinctive feature of the transition of mesenchymal stromal cells (h-MSCs) toward mature osteoblast. Furthermore, loss of function experiments on CBS and CSE during osteogenic differentiation of h-MSCs revealed an impaired mineralization ability. In vivo experiments in mice highlighted the role of CBS, CSE and H2S in the maintenance of bone homeostasis and CBS, CSE and H2S were found to be depleted in post-menopausal osteoporosis. Furthermore, our in vitro and in vivo data validated the use of H2S-donors as novel potential candidates for the treatment of bone pathologies. In particular H2S administration prevented and reversed ovariectomy-induced bone loss in mice. Based on these evidences, we firstly developed an H2S-releasing hybrid drug (DM-22) by modifying a clinically relevant anti-resorptive drug in order to improve the therapy of bone loss. DM-22 displayed improved biological properties compared to the parent drug; in particular, it increased the osteogenic differentiation ability of h-MSCs. Secondly, we developed an H2S-releasing scaffold to improve bone regeneration which was permissive for h-MSCs colonization and supported their osteogenic differentiation

Sulfurous thermal waters stimulate the osteogenic differentiation of human mesenchymal stromal cells - An in vitro study.

Strategies aimed at delaying the onset of bone tissue degeneration and the resulting skeletal fragility are key to decrease the risk of bone fracture correlated to ageing. The therapeutic properties of sulfurous thermal waters (STWs), rich in hydrogen sulfide (H2S), have been claimed for centuries. However, the direct regulation of bone cells by STWs has not been investigated yet. Here we aimed at analyzing the effect of STWs on cultured human mesenchymal stromal cells (hMSCs) derived from bone tissue. Two concentrations of STWs from 2 health spa centers in Italy (here named STW-1 and STW-2) containing, respectively, high and moderate quantities of H2S, were added to the culture media. Cytotoxicity and osteogenic differentiation were evaluated. We provided first evidence that treatment of hMSCs with STWs results in a sharp increase in intracellular H2S content, coherent with the different concentrations of H2S, thereby reveling that STWs-released H2S is internalized by cells. STWs treatment significantly induced osteogenic differentiation of hMSCs. In particular, mineral apposition was increased with a similar pattern by the two STWs, while mRNA expression of osteogenic markers (BSP, OC, RUNX-2, OPN) was differently affected. Only STW-2 induced a significant, dose-dependent increase in these gene expression. These findings support the rationale for the use of STWs as a complementary treatment of bone wasting diseases

Methacrylated Silk Fibroin Additive Manufacturing of Shape Memory Constructs with Possible Application in Bone Regeneration

: Methacrylated silk (Sil-MA) is a chemically modified silk fibroin specifically designed to be crosslinkable under UV light, which makes this material applicable in additive manufacturing techniques and allows the prototyping and development of patient-specific 2D or 3D constructs. In this study, we produced a thin grid structure based on crosslinked Sil-MA that can be withdrawn and ejected and that can recover its shape after rehydration. A complete chemical and physical characterization of Sil-MA was first conducted. Additionally, we tested Sil-MA biocompatibility according to the International Standard Organization protocols (ISO 10993) ensuring the possibility of using it in future trials. Sil-MA was also tested to verify its ability to support osteogenesis. Overall, Sil-MA was shown to be biocompatible and osteoconductive. Finally, two different additive manufacturing technologies, a Digital Light Processing (DLP) UV projector and a pneumatic extrusion technique, were used to develop a Sil-MA grid construct. A proof-of-concept of its shape-memory property was provided. Together, our data support the hypothesis that Sil-MA grid constructs can be injectable and applicable in bone regeneration applications

A Novel H2S-releasing Amino-Bisphosphonate which combines bone anti-catabolic and anabolic functions

Bisphosphonates (BPs) are the first-line treatment of bone loss resulting from various pathological conditions. Due to their high affinity to bone they have been used to develop conjugates with pro-Anabolic or anti-catabolic drugs. We recently demontrated that hydrogen sulfide (H2S), promotes osteogenesis and inhibits osteoclast differentiation. Here we developed an innovative molecule, named DM-22, obtained from the combination of alendronate (AL) and the H2S-releasing moiety aryl-isothiocyanate. DM-22 and AL were assayed in vitro in the concentration range 1-33 μM for effects on viability and function of human osteoclasts (h-OCs) and mesenchymal stromal cells (h-MSCs) undergoing osteogenic differentiation. Amperometric measures revealed that DM-22 releases H2S at a slow rate with a thiol-dependent mechanism. DM-22 significantly inhibited h-OCs differentiation and function, maintaining a residual h-OCs viability even at the high dose of 33 μM. Contrary to AL, in h-MSCs DM-22 did not induce cytotoxicity as revealed by LDH assay, significantly stimulated mineralization as measured by Alizarin Red staining and increased mRNA expression of Collagen I as compared to control cultures. In conclusion, DM-22 is a new BP which inhibits h-OCs function and stimulate osteogenic differentiation of h-MSCs, without cytotoxicity. DM-22 is an ideal candidate for a novel family of osteoanabolic drugs

Docking of molecules identified in bioactive medicinal plants extracts into the p50 NF-kappaB transcription factor: correlation with inhibition of NF-kappaB/DNA interactions and inhibitory effects on IL-8 gene expression

<p>Abstract</p> <p>Background</p> <p>The transcription factor NF-kappaB is a very interesting target molecule for the design on anti-tumor, anti-inflammatory and pro-apoptotic drugs. However, the application of the widely-used molecular docking computational method for the virtual screening of chemical libraries on NF-kappaB is not yet reported in literature. Docking studies on a dataset of 27 molecules from extracts of two different medicinal plants to NF-kappaB-p50 were performed with the purpose of developing a docking protocol fit for the target under study.</p> <p>Results</p> <p>We enhanced the simple docking procedure by means of a sort of combined target- and ligand-based drug design approach. Advantages of this combination strategy, based on a similarity parameter for the identification of weak binding chemical entities, are illustrated in this work with the discovery of a new lead compound for NF-kappaB. Further biochemical analyses based on EMSA were performed and biological effects were tested on the compound exhibiting the best docking score. All experimental analysis were in fairly good agreement with molecular modeling findings.</p> <p>Conclusion</p> <p>The results obtained sustain the concept that the docking performance is predictive of a biochemical activity. In this respect, this paper represents the first example of successfully individuation through molecular docking simulations of a promising lead compound for the inhibition of NF-kappaB-p50 biological activity and modulation of the expression of the NF-kB regulated IL8 gene.</p

Differential expression of microRNA501-5p affects the aggressiveness of clear cell renal carcinoma

AbstractRenal cell carcinoma is a common neoplasia of the adult kidney that accounts for about 3% of adult malignancies. Clear cell renal carcinoma is the most frequent subtype of kidney cancer and 20–40% of patients develop metastases. The absence of appropriate biomarkers complicates diagnosis and prognosis of this disease. In this regard, small noncoding RNAs (microRNAs), which are mutated in several neoplastic diseases including kidney carcinoma, may be optimal candidates as biomarkers for diagnosis and prognosis of this kind of cancer. Here we show that patients with clear cell kidney carcinoma that express low levels of miR501-5p exhibited a good prognosis compared with patients with unchanged or high levels of this microRNA. Consistently, in kidney carcinoma cells the downregulation of miR501-5p induced an increased caspase-3 activity, p53 expression as well as decreased mTOR activation, leading to stimulation of the apoptotic pathway. Conversely, miR501-5p upregulation enhanced the activity of mTOR and promoted both cell proliferation and survival. These biological processes occurred through p53 inactivation by proteasome degradation in a mechanism involving MDM2-mediated p53 ubiquitination. Our results support a role for miR501-5p in balancing apoptosis and cell survival in clear cell renal carcinoma. In particular, the downregulation of microRNA501-5p promotes a good prognosis, while its upregulation contributes to a poor prognosis, in particular, if associated with p53 and MDM2 overexpression and mTOR activation. Thus, the expression of miR501-5p is a possible biomarker for the prognosis of clear cell renal carcinoma

A validated cellular biobank for β-thalassemia

Background: Cellular biobanking is a key resource for collaborative networks planning to use same cells in studies aimed at solving a variety of biological and biomedical issues. This approach is of great importance in studies on β-thalassemia, since the recruitment of patients and collection of specimens can represent a crucial and often limiting factor in the experimental planning. Methods: Erythroid precursor cells were obtained from 72 patients, mostly β-thalassemic, expanded and cryopreserved. Expression of globin genes was analyzed by real time RT-qPCR. Hemoglobin production was studied by HPLC. Results: In this paper we describe the production and validation of a Thal-Biobank constituted by expanded erythroid precursor cells from β-thalassemia patients. The biobanked samples were validated for maintenance of their phenotype after (a) cell isolation from same patients during independent phlebotomies, (b) freezing step in different biobanked cryovials, (c) thawing step and analysis at different time points. Reproducibility was confirmed by shipping the frozen biobanked cells to different laboratories, where the cells were thawed, cultured and analyzed using the same standardized procedures. The biobanked cells were stratified on the basis of their baseline level of fetal hemoglobin production and exposed to fetal hemoglobin inducers. Conclusion: The use of biobanked cells allows stratification of the patients with respect to fetal hemoglobin production and can be used for determining the response to the fetal hemoglobin inducer hydroxyurea and to gene therapy protocols with reproducible results

Therapeutic Hemoglobin Levels after Gene Transfer in β-Thalassemia Mice and in Hematopoietic Cells of β-Thalassemia and Sickle Cells Disease Patients

Preclinical and clinical studies demonstrate the feasibility of treating β-thalassemia and Sickle Cell Disease (SCD) by lentiviral-mediated transfer of the human β-globin gene. However, previous studies have not addressed whether the ability of lentiviral vectors to increase hemoglobin synthesis might vary in different patients