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MicroRNAs (miRNAs or miRs) are a family of small non-coding RNAs that regulate gene expression by the sequence-selective targeting of mRNAs, leading to translational repression or mRNA degradation, depending on the degree of complementarity with target mRNA sequences. miRNAs play a crucial role in cancer. In the case of breast tumors, several studies have demonstrated a correlation between: i) the expression profile of oncogenic miRNAs (oncomiRs) or tumor suppressor miRNAs and ii) the tumorigenic potential of triple-negative [estrogen receptor (ER), progesterone receptor (PR) and Her2/neu] primary breast cancers. Among the miRNAs involved in breast cancer, miR-221 plays a crucial role for the following reasons: i) miR-221 is significantly overexpressed in triple-negative primary breast cancers; ii) the oncosuppressor p27 Kip1 , a validated miR-221 target, is downregulated in aggressive cancer cell lines; and iii) the upregulation of a key transcription factor, Slug, appears to be crucial, since it binds to the miR-221/miR-222 promoter and is responsible for the high expression of the miR-221/miR-222 cluster in breast cancer cells. A Slug/miR-221 network has been suggested, linking miR-221 activity with the downregulation of a Slug repressor, leading to Slug/miR-221 upregulation and p27 Kip1 downregulation. Interference with this process can be achieved using antisense miRNA (antagomiR) molecules targeting miR-221, inducing the down-regulation of Slug and the upregulation of p27 Kip1 .

There is a growing demand for the development of experimental strategies for efficient articular cartilage repair. Current tissue engineering-based regenerative strategies make use of human mesenchymal stromal cells (hMSCs). However, when implanted in a cartilage defect, control of hMSCs differentiation toward the chondrogenic lineage remains a significant challenge. We have recently demonstrated that silencing the antichondrogenic regulator microRNA-221 (miR-221) was highly effective in promoting in vitro chondrogenesis of monolayered hMSCs in the absence of the chondrogenic induction factor TGF-b. Here we investigated the feasibility of this approach first in conventional 3D pellet culture and then in an in vivo model. In pellet cultures, we observed that miR-221 silencing was sufficient to drive hMSCs toward chondrogenic differentiation in the absence of TGF-b. In vivo, the potential of miR-221 silenced hMSCs was investigated by first encapsulating the cells in alginate and then by filling a cartilage defect in an osteochondral biopsy. After implanting the biopsy subcutaneously in nude mice, we found that silencing of miR-221 strongly enhanced in vivo cartilage repair compared to the control conditions (untreated hMSCs or alginate-only). Notably, miR-221 silenced hMSCs generated in vivo a cartilaginous tissue with no sign of collagen type X deposition, a marker of undesired hypertrophic maturation. Altogether our data indicate that silencing miR-221 has a prochondrogenic role in vivo, opening new possibilities for the use of hMSCs in cartilage tissue engineering. STEM CELLS 2016;34:1801-1811 SIGNIFICANCE STATEMENTWe demonstrated here the effectiveness of an innovative approach based on transient transfection of inhibitor of antichondrogenic miR-221 to direct human mesenchymal stromal cells (hMSCs) toward chondrogenesis both in vitro and in vivo, without exposure to the chondrogenic inducer TGF-b. miR-221 knockdown was sufficient to repair an osteochondral defect subcutaneously implanted in mice, promoting the production of newly formed tissue expressing Collagen type II but not Collagen type X. It is well known that the expression of Collagen type X, a marker for chondrocyte hypertrophy, is an undesired outcome and remains an issue to be solved in the cell-based approach for cartilage regeneration. Therefore, the ability of miR-221 depleted hMSCs to downregulate Collagen type X, both in vitro and in vivo, represents a crucial event on formation of cartilaginous repair tissue and a promising approach to translate into the clinic.

Gender medicine is the first step of personalized medicine and patient-centred care, an essential development to achieve the standard goal of a holistic approach to patients and diseases. By addressing the interrelation and integration of biological markers (i.e., sex) with indicators of psychological/cultural behaviour (i.e., gender), gender medicine represents the crucial assumption for achieving the personalized health-care required in the third millennium. However, ‘sex’ and ‘gender’ are often misused as synonyms, leading to frequent misunderstandings in those who are not deeply involved in the field. Overall, we have to face the evidence that biological, genetic, epigenetic, psycho-social, cultural, and environmental factors mutually interact in defining sex/gender differences, and at the same time in establishing potential unwanted sex/gender disparities. Prioritizing the role of sex/gender in physiological and pathological processes is crucial in terms of efficient prevention, clinical signs’ identification, prognosis definition, and therapy optimization. In this regard, the omics-approach has become a powerful tool to identify sex/gender-specific disease markers, with potential benefits also in terms of socio-psychological wellbeing for each individual, and cost-effectiveness for National Healthcare systems. “Being a male or being a female” is indeed important from a health point of view and it is no longer possible to avoid “sex and gender lens” when approaching patients. Accordingly, personalized healthcare must be based on evidence from targeted research studies aimed at understanding how sex and gender influence health across the entire life span. The rapid development of genetic tools in the molecular medicine approaches and their impact in healthcare is an example of highly specialized applications that have moved from specialists to primary care providers (e.g., pharmacogenetic and pharmacogenomic applications in routine medical practice). Gender medicine needs to follow the same path and become an established medical approach. To face the genetic, molecular and pharmacological bases of the existing sex/gender gap by means of omics approaches will pave the way to the discovery and identification of novel drug-targets/therapeutic protocols, personalized laboratory tests and diagnostic procedures (sex/gender-omics). In this scenario, the aim of the present review is not to simply resume the state-of-the-art in the field, rather an opportunity to gain insights into gender medicine, spanning from molecular up to social and psychological stances. The description and critical discussion of some key selected multidisciplinary topics considered as paradigmatic of sex/gender differences and sex/gender inequalities will allow to draft and design strategies useful to fill the existing gap and move forward.

In order to study the pathogenesis of gingival overgrowth induced by the immunosuppressive drug cyclosporine-A (CyA), we investigated its effect on 3H thymidine incorporation and on collagen production and mRNA levels in fibroblast cultures obtained from normal human gingiva. At concentrations of 100, 500 and 1000 ng/ml, CyA did not modify thymidine incorporation after 24 and 72 h of incubation. However, after 24 h it significantly increased the level of 3H proline-containing proteins in the medium. In addition, CyA increased alpha-procollagen chains by up to three times. This CyA-induced change was related to a rise in the level of type I procollagen. The CyA effect on fibroblasts was markedly reduced by cycloheximide, an inhibitor of protein synthesis, and it correlated well with an increase of type I procollagen mRNA. Overall, our data indicate a direct stimulatory action of CyA on collagen synthesis, but not on DNA synthesis, in human gingival fibroblasts.

In this study we have inhibited the expression of two negative regulators of chondrogenesis, Slug transcription factor (TF) and the small non-coding single stranded RNA microRNA-221 (miR-221), in human mesenchymal stem cells (MSCs). Our aim was test a new approach to guide the cells toward a chondrocyte - like phenotype, without the employment of differentiating agents, in the prospect of their clinical applications for cell-based cartilage tissue engineering. We have characterized these manipulated cells by gene expression analysis at the RNA and protein levels. We demonstrated that decreased miR-221 or Slug induced an increase of chondrogenic markers, including collagen type II (Col2A1), and the positive chondrogenic TFs Sox9 and TRPS1. Slug and TRPS1 are not direct targets of miR-221 since their expression was not affected by miR-221 content. Further, we showed by gene expression and Chromatin Immunoprecipitation analyses that i. miR-221 is positively regulated by Slug in hMSCs, where Slug and miR-221 high levels hamper cell differentiation, and ii. TRPS1 contributes to maintaining low levels of miR-221, both in hMSCs committed toward chondrogenesis by Slug depletion and in chondrocytes, where the low levels of miR-221 and Slug allow a chondrogenic phenotype.Taken together, our data may be relevant both to understand yet unknown miRNA - TF regulatory loops in cartilage biology and to establish new strategies based on a siRNA approach for cartilage tissue engineering.

The description of a microencapsulation procedure for Wharton's jelly mesenchymal stem cells (WJMSCs) is reported. The applied method is based on the generation of monodisperse droplets by a vibrational nozzle. An ionic alginate encapsulation procedure was utilized for the microbeads hardening. Different experimental parameters were analyzed, including frequency and amplitude of vibration, polymer pumping rate, and distance between the nozzle and the gelling bath. The produced barium-alginate microbeads were characterized by excellent morphological characteristics as well as a very narrow size distribution. The microencapsulation procedure did not alter the morphology and viability of the encapsulated WJMSCs. In addition, the current paper reports the functional properties in terms of secretive profiles of both free and encapsulated WJMSCs. The analyzed factors were members of the family of interleukins, chemokines, growth factors, and soluble forms of adhesion molecules. These experiments showed that despite encapsulation, most of the proteins analyzed were secreted both by the free and encapsulated cells, even if in a different extent. In conclusion, the described encapsulation procedure represents a promising strategy to utilize WJMSCs for possible in vivo applications in tissue engineering and biomedicine.

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