Persistent Sweet syndrome post-hematopoietic stem cell transplantation heralding molecular relapse of myelofibrosis.

Persistent Sweet syndrome in a patient with history of myelofibrosis thought to be in remission post-hematopoietic stem cell transplantation leads to diagnosis of molecular relapse of myelofibrosis.

Studying the in vivo application of a liquid dermal scaffold in promoting wound healing in a mouse model.

Lack of matrix deposition is one of the main factors that complicates the healing process of wounds. The aim of this study was to test the efficacy and safety of a liquid dermal scaffold, referred to as MeshFill (MF) that can fill the complex network of tunnels and cavities which are usually found in chronic wounds and hence improve the healing process. We evaluated in vitro and in vivo properties of a novel liquid dermal scaffold in a delayed murine full-thickness wound model. We also compared this scaffold with two commercially available granular collagen-based products (GCBP). Liquid dermal scaffold accelerated wound closure significantly compared with no-treated control and collagen-based injectable composites in a delayed splinted wound model. When we compared cellular composition and count between MF, no treatment and GCBP at the histology level, it was found that MF was the most analogous and consistent with the normal anatomy of the skin. These findings were matched with the clinical outcome observation. The flowable in situ forming scaffold is liquid at cold temperature and gels after application to the wound site. Therefore, it would conform to the topography of the wound when liquid and provides adequate tensile strength when solidified. This patient-ready gelling dermal scaffold also contains the nutritional ingredients and therefore supports cell growth. Applying an injectable liquid scaffold that can fill wound gaps and generate a matrix to promote keratinocytes and fibroblasts migration, can result in improvement of the healing process of complex wounds.

Increased expression of PD-L1 and PD-L2 in dermal fibroblasts from alopecia areata mice.

Alopecia areata (AA) is a common autoimmune disorder affecting millions of people worldwide, which manifests as a sudden, non-scarring hair loss. The expression of a pro-inflammatory cytokine, interferon-gamma (INF-γ), has been well established to be involved in the development of AA. As IFN-γ and other cytokines are also known to up-regulate programmed cell death ligand 1 and 2 (PD-L1 and PD-L2), which both negatively control immune responses, we asked whether or not a high number of infiltrated T cells, seen in AA lesions, can modulate the expression of PD-L1 and PD-L2 in skin cells. From a series of experiments, we showed that a significantly higher number of PD-L1 or PD-L2 positive cells affect the skin in AA mice, compared to the skin of non-AA mice. The number of PD-L1 positive cells was well correlated with the number of infiltrated T cells, especially CD8+ T cells. We also found that the expression of PD-L1 and PD-L2 was co-localized with type 1 pro-collagen, CD90 and vimentin, which are biomarkers for dermal fibroblasts. Further studies revealed that releasable factors from activated, but not inactivated, lymphocytes significantly increase the expressions of both PD-L1 and PD-L2 in cultured dermal fibroblasts. In conclusion, our findings suggest that the expression of PD-L1 and PD-L2 in dermal fibroblasts is up-regulated by activated T cells in AA-affected skin, and as such, these regulatory molecules may not exert a negative control of the immune activation seen in AA lesions.

Intraperitoneal injection of IDO-expressing dermal fibroblasts improves the allograft survival.

Indoleamine 2,3-dioxygenase (IDO) is an immunosuppressive enzyme with tolerogenic effects on different immune cells. Our group has previously shown that co-transplantation of IDO-expressing fibroblasts with donor tissues can delay immune rejection by inducing local immunosuppression. In this study, we have employed a systemic approach to improve allograft survival without using any immunosuppressive medication. To achieve this, 10 million lentiviral transduced IDO-expressing donor derived fibroblasts were injected into the peritoneal cavity of allograft recipients. We showed that IDO-fibroblast therapy increases the survival of both islets and skin allografts and decreases the infiltration of immune cells in subcutaneous transplanted skins. Indirect pathway of allo-reactive T cell activation was suppressed more than the direct pathway. Injected IDO-fibroblasts were found in peritoneal cavity and mesenteric lymph nodes of the recipient mice. In conclusion, IDO-expressing fibroblast therapy proved to be a novel approach in improving the allogeneic graft survival.

Tolerogenic effect of mouse fibroblasts on dendritic cells.

There is controversy about the immunomodulatory effect of fibroblasts on dendritic cells (DCs). To clarify this issue, in this study, we have evaluated different features of fibroblast-primed DCs including their ability to express co-inhibitory and co-stimulatory molecules, pro-inflammatory and anti-inflammatory cytokines and their ability to induce T-cell proliferation. We also examined migratory capacity of DCs to lymphatic tissues and present fibroblast-derived antigens after encountering fibroblasts. The results of our in vitro study showed that both co-inhibitory (programmed death ligand 1 and ligand 2 and B7H4) and co-stimulatory (CD86) molecules were up-regulated when DCs were co-cultured with fibroblasts. In an animal model, we showed that intra- peritoneal injection (IP) of both syngeneic and allogeneic fibroblasts significantly increased both total DC count and expression level of co-inhibitory and co-stimulatory molecules on DCs. Priming of DCs with syngeneic and allogeneic fibroblasts reduced the proliferation of CD4(+) and CD8(+) T cells. Even activation of fibroblast- primed DCs failed to restore their ability to induce T-cell proliferation. Likewise, priming of DCs with fibroblasts blocked the ability of ovalbumin-pulsed DCs to induce proliferation of ovalbumin-specific CD4(+) T cells. Compared with non-activated DCs, fibroblast-primed DCs had significantly higher expression levels of interleukin-10 and indoleamine 2, 3 dioxygenase. Fibroblast-primed DCs had a significantly reduced interleukin-12 expression level compared with that of activated DCs. After priming with fibroblasts, DCs were able to migrate to lymphatic tissues and present fibroblast-derived antigens (ovalbumin). In conclusion, after priming with fibroblasts, DCs gain tolerogenic features. This finding suggests the potential role of fibroblasts in the maintenance of immune tolerance.

A new method for skin grafting in murine model.

Skin transplantation provides an excellent potential model to investigate the immunology of allograft rejection and tolerance induction. Despite the theoretical ease of performing skin transplantation, as well as the potential of directly observing the reaction to the transplanted tissue, the poor reliability of skin transplantation in the mouse has largely precluded the use of this model. Furthermore, there is controversy regarding the most appropriate skin graft donor site due to poor success of back skin transplantation, as compared with the thinner ear or tail skin. This study demonstrates a reliable method to successfully perform skin grafts in a mouse model, as well as the clinical and histologic outcome of syngeneic grafts. A total of 287 grafts were performed (in 126 mice) utilizing donor skin from the ear, tail or back. No graft failure or postoperative mortality was observed. Comparison of this technique with two previously established protocols of skin transplantation (5.0 absorbable Suture + tissue glue technique and no-suture technique) demonstrates the significant improvement in the engraftment success of the new technique. In summary, a new technique for murine skin grafting demonstrates improved reliability across donor site locations and strains, increasing the potential for investigating interventions to alter the rejection process.

Concurrent PTEN and PDGFRB Alterations Characterize Storiform Collagenoma.

Storiform collagenoma is a rare mesenchymal skin tumor that is composed of thickened collagen bundles arranged in a characteristic storiform pattern with a relatively hypocellular CD34-positive spindle cell component. Storiform collagenoma is most often sporadic, but multiple lesions can occur in Cowden syndrome, which is characterized by germline alterations in PTEN (phosphatase and tensin homolog) on chromosome 10. Here, we investigated the molecular pathogenesis of storiform collagenoma using a targeted next-generation DNA sequencing platform, including 5 sporadic cases and one case associated with Cowden syndrome. Recurrent PTEN alterations were identified in all cases, with biallelic PTEN inactivation observed in the case associated with Cowden syndrome and one sporadic case. Unexpectedly, we also identified recurrent activating mutations in the platelet-derived growth factor receptor beta ( PDGFRB ) gene. This included a missense substitution in the D5 Ig-like domain of PDGFRB in the Cowden syndrome-associated case. In addition, we report missense alterations in the juxtamembrane domain of PDGFRB in 4 of 5 (80%) sporadic cases, including mutations that have been previously described in sporadic myofibroma and myopericytoma. Therefore, we confirm the neoplastic nature of storiform collagenoma, we expand the spectrum of reported PDGFRB alterations in mesenchymal tumors and we suggest a possible collaborative role for PTEN and PDGFRB in the pathogenesis of storiform collagenoma.

Immunotherapy, targeted therapy, and their cross talks in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a challenging malignancy with limited treatment options beyond surgery and chemotherapy. Recent advancements in targeted therapies and immunotherapy, including PD-1 and PD-L1 monoclonal antibodies, have shown promise, but their efficacy has not met expectations. Biomarker testing and personalized medicine based on genetic mutations and other biomarkers represent the future direction for HCC treatment. To address these challenges and opportunities, this comprehensive review discusses the progress made in targeted therapies and immunotherapies for HCC, focusing on dissecting the rationales, opportunities, and challenges for combining these modalities. The liver's unique physiology and the presence of fibrosis in many HCC patients pose additional challenges to drug delivery and efficacy. Ongoing efforts in biomarker development and combination therapy design, especially in the context of immunotherapies, hold promise for improving outcomes in advanced HCC. Through exploring the advancements in biomarkers and targeted therapies, this review provides insights into the challenges and opportunities in the field and proposes strategies for rational combination therapy design.

Local Expression of Indoleamine 2,3, Dioxygenase Prolongs Allogenic Skin Graft Take in a Mouse Model.

Background and Objective: Despite the effectiveness of skin autotransplantation, the high degree of immunogenicity of the skin precludes the use of allografts and systemic immunosuppression is generally inappropriate for isolated skin grafts. Indoleamine 2,3 dioxygenase (IDO) is a potent immunoregulatory factor with allo- and autoimmune suppression and tolerance induction properties. This study examines the potential use of locally expressed IDO to prolong the allogeneic skin graft take in a mouse model. Approach: Syngeneic-fibroblasts were transfected with noncompetent IDO viral vector and the level of Kynurenine (Kyn) in conditioned medium was measured as an index for IDO activity. Either 1 or 3 × 106 IDO-fibroblasts were introduced intra/hypo-dermally to the mouse skin. The expression, localization, and functionality of IDO were then evaluated. The cell-injected areas were harvested and grafted on the back of allogeneic mice. The graft survival, immune-cells infiltration, and interaction with dendritic cells were evaluated. Results: The results showed a significant improvement in allogeneic graft take injected with 1 × 106 IDO-fibroblasts (18.4 ± 3.3 days) compared with control (12.2 ± 1.9 days). This duration increased to 35.4 ± 4.7 days in grafts injected with 3 × 106 IDO-expressing cells. This observation might be due to a significantly lower T cells infiltration within the IDO-grafts. Further, the result of a flow cytometric analysis showed that the expression of PD-L1/PD-L2 on CD11c+/eFluor+ cells in the regional lymph nodes of injected skin areas was significantly higher in IDO groups compared with control. Conclusion: These data suggest that allogeneic skin graft survival outcome can be prolonged significantly by local overexpression of IDO without any systemic effect.

IDO-expressing Fibroblasts Suppress the Development of Imiquimod-induced Psoriasis-like Dermatitis.

Psoriasis is a chronic skin condition whose pathogenesis is reported to be due to the activation of the interleukin-23/interleukin-17 (IL-23/IL-17) pathway. Here, we report that indoleamine 2,3-dioxygenase (IDO)-expressing fibroblasts reduce the activity of this pathway in activated immune cells. The findings showed that intralesional injection of IDO-expressing fibroblasts in imiquimod-induced psoriasis-like dermatitis on the back and ear (Pso. ear group) in mice significantly improves the clinical lesional appearance by reducing the number of skin-infiltrated IL-17+ CD4+ T cells (1.9% ± 0.3% vs. 6.9% ± 0.6%, n = 3, P value < 0.01), IL-17+ γδ+ T cells (2.8% ± 0.3% vs. 11.6% ± 1.2%, n = 3, P value < 0.01), IL-23+ activated dendritic cells (7.6% ± 0.9% vs. 14.0% ± 0.5%, n = 3, P < 0.01), macrophages (4.3% ± 0.1% vs. 11.3% ± 1.0%, n = 3, P value < 0.01), and granulocytes (2.5% ± 0.4% vs. 4.5% ± 0.3%, n = 3, P value < 0.01) as compared to untreated psoriatic mice. This finding suggests that IDO-expressing fibroblasts, and to a lesser extent, non-IDO primary fibroblasts suppress the psoriatic-like symptoms by inhibiting the infiltration of key immune cells involved in the development of psoriasis.

Evaluation of Detergent-Free and Detergent-Based Methods for Decellularization of Murine Skin.

Acute and chronic wounds contribute to increased morbidity and mortality in affected people and impose significant financial burdens on healthcare systems. For these challenging wounds, acellular dermal matrices (ADMs) have been used as a biological wound coverage. Unlike engineered dermal matrices, ADMs are prepared through the removal of cells from skin, while preserving the extracellular matrix structure and function. In this study, our primary objective was to develop a detergent-free method for decellularization of the skin to mitigate chemical stress on matrix molecules. Then, we performed a set of in vitro and in vivo experiments to compare this method with nonionic and anionic detergent methods. All decellularization methods satisfactorily removed cells and supported fibroblast growth and migration in vitro. Sulfated glycosaminoglycan content was reduced significantly (p < 0.05) only in the ionic detergent treatment group. In contrast to the detergent-free method, all detergent-based methods significantly reduced scaffold mechanical strength and elastin content (p < 0.05). Three weeks after transplantation, the results showed reepithelialization, angiogenesis, and migration of host cell into scaffolds with no induction of immunogenic reaction in all ADM groups tested. In our study, the detergent-free method showed better preservation of matrix composition and biomechanical properties, but after transplantation, all methods of ADM preparation resulted in equally biofunctional matrices as wound coverage.

Development of a nanofibrous wound dressing with an antifibrogenic properties in vitro and in vivo model.

Dermal fibrosis, characterized by excessive extracellular matrix (ECM), is a pathological condition with limited effective therapeutic modalities. Lack of an antiscarring dressing further impedes the preventive measures for this condition. Here, we develop a new antiscarring dressing and investigate its potential as a slow-releasing vehicle for kynurenic acid (KynA), an antifibrotic agent. KynA was incorporated into polymethyl methacrylate (PMMA) nanofibers, containing increasing concentration of polyethylene glycol (PEG). Fibre morphology, water absorption capacity, surface hydrophilicity, in vitro drug release profile, and in vivo antifibrotic effects were investigated. Increasing concentrations of PEG (1-20%) significantly increased surface hydrophilicity, water absorption capacity, and drug release. Based on the obtained release profiles, PMMA + 10% PEG was the preferred formulation for sustained KynA release up to 120 hours. In vitro studies confirmed the preservation of KynA antifibrotic properties during electrospinning, indicated by fibroblasts proliferation suppression and ECM expression modulation. In vivo application of KynA-incorporated films significantly inhibited collagen (23.89 ± 4.79 vs. 6.99 ± 0.41, collagen-I/ß-actin mRNA expression, control vs. treated) and fibronectin expression (7.18 ± 1.09 vs. 2.31 ± 0.05, fibronectin/ß-actin mRNA expression, control vs. treated) and enhanced the production of an ECM-degrading enzyme (2.03 ± 0.88 vs. 11.88 ± 1.16 MMP-1/ß-actin mRNA expression, control vs. treated). The fabricated KynA-incorporated films can be exploited as antifibrotic wound dressings. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2334-2344, 2016.

Critical Role of Transforming Growth Factor Beta in Different Phases of Wound Healing.

SIGNIFICANCE: This review highlights the critical role of transforming growth factor beta (TGF-ß)1-3 within different phases of wound healing, in particular, late-stage wound healing. It is also very important to identify the TGF-ß1-controlling factors involved in slowing down the healing process upon wound epithelialization. RECENT ADVANCES: TGF-ß1, as a growth factor, is a known proponent of dermal fibrosis. Several strategies to modulate or regulate TGF's actions have been thoroughly investigated in an effort to create successful therapies. This study reviews current discourse regarding the many roles of TGF-ß1 in wound healing by modulating infiltrated immune cells and the extracellular matrix. CRITICAL ISSUES: It is well established that TGF-ß1 functions as a wound-healing promoting factor, and thereby if in excess it may lead to overhealing outcomes, such as hypertrophic scarring and keloid. Thus, the regulation of TGF-ß1 in the later stages of the healing process remains as critical issue of which to better understand. FUTURE DIRECTIONS: One hypothesis is that cell communication is the key to regulate later stages of wound healing. To elucidate the role of keratinocyte/fibroblast cross talk in controlling the later stages of wound healing we need to: (1) identify those keratinocyte-released factors which would function as wound-healing stop signals, (2) evaluate the functionality of these factors in controlling the outcome of the healing process, and (3) formulate topical vehicles for these antifibrogenic factors to improve or even prevent the development of hypertrophic scarring and keloids as a result of deep trauma, burn injuries, and any type of surgical incision.