MSCs rescue impaired wound healing in a murine LAD1 model by adaptive responses to low TGF-ß1 levels.

Mutations in the CD18 gene encoding the common ß-chain of ß2 integrins result in impaired wound healing in humans and mice suffering from leukocyte adhesion deficiency syndrome type 1 (LAD1). Transplantation of adipose tissue-derived mesenchymal stem cells (MSCs) restores normal healing of CD18-/- wounds by restoring the decreased TGF-ß1 concentrations. TGF-ß1 released from MSCs leads to enhanced myofibroblast differentiation, wound contraction, and vessel formation. We uncover that MSCs are equipped with a sensing mechanism for TGF-ß1 concentrations at wound sites. Low TGF-ß1 concentrations as occurring in CD18-/- wounds induce TGF-ß1 release from MSCs, whereas high TGF-ß1 concentrations suppress TGF-ß1 production. This regulation depends on TGF-ß receptor sensing and is relayed to microRNA-21 (miR-21), which subsequently suppresses the translation of Smad7, the negative regulator of TGF-ß1 signaling. Inactivation of TGF-ß receptor, or overexpression or silencing of miR-21 or Smad7, abrogates TGF-ß1 sensing, and thus prevents the adaptive MSC responses required for tissue repair.

Ultrasonography in dermatologic surgery: revealing the unseen for improved surgical planning.

Ultrasonography (US) is a modern, in vivo imaging method, which is increasingly being used in dermatology as a complementary tool to clinical examination and dermoscopy. At higher frequencies (15 MHz and above), US is an established method for assessing benign and malignant skin lesions, locoregional staging, monitoring the therapeutic efficacy in various inflammatory skin conditions, and patient follow-up. One field, which may increasingly benefit from performant imaging techniques such as US is dermatologic surgery. Preoperative imaging of cutaneous tumors, inflammatory skin conditions (hidradenitis suppurativa, abscesses, etc.), or nail pathology provide dermatologic surgeons with relevant information for an optimal surgical planning, identifying potential complex aspects which might require interdisciplinary approaches, herein sparing unnecessary surgical interventions and increasing patients' compliance. In this review, we discuss the increasing significance of US in the field of dermatologic surgery, as well as the spectrum of cutaneous pathology where sonography can aid in the preoperative setting to provide a more precise, individualized surgical planning for better counseling to our patients and improved surgical results.

Newly Defined ATP-Binding Cassette Subfamily B Member 5 Positive Dermal Mesenchymal Stem Cells Promote Healing of Chronic Iron-Overload Wounds via Secretion of Interleukin-1 Receptor Antagonist.

In this study, we report the beneficial effects of a newly identified dermal cell subpopulation expressing the ATP-binding cassette subfamily B member 5 (ABCB5) for the therapy of nonhealing wounds. Local administration of dermal ABCB5+ -derived mesenchymal stem cells (MSCs) attenuated macrophage-dominated inflammation and thereby accelerated healing of full-thickness excisional wounds in the iron-overload mouse model mimicking the nonhealing state of human venous leg ulcers. The observed beneficial effects were due to interleukin-1 receptor antagonist (IL-1RA) secreted by ABCB5+ -derived MSCs, which dampened inflammation and shifted the prevalence of unrestrained proinflammatory M1 macrophages toward repair promoting anti-inflammatory M2 macrophages at the wound site. The beneficial anti-inflammatory effect of IL-1RA released from ABCB5+ -derived MSCs on human wound macrophages was conserved in humanized NOD-scid IL2rγ null mice. In conclusion, human dermal ABCB5+ cells represent a novel, easily accessible, and marker-enriched source of MSCs, which holds substantial promise to successfully treat chronic nonhealing wounds in humans. Stem Cells 2019;37:1057-1074.

How can nanoparticle-based technologies revolutionize the topical therapy in psoriasis?

Psoriasis is one of the most common dermatoses with a heterogeneous pathogenesis which can be successfully exploited therapeutically as it is increasingly well understood. Topical therapy is the gold standard for psoriasis patients with mild disease courses and for complementary and maintenance treatment in moderate and severe forms. However, while new systemic therapies are rapidly implemented in the daily routine as our pathomechanistic understanding of psoriasis evolves, the development of topical psoriasis therapies stagnates. Modern topical treatments though would require not only new active substances but also improved galenics. Due to their unique ability to directly exert biological functions, but also to deliver drugs in optimal concentrations, enabling increased therapeutic efficacy, reduced adverse effects and improved patient compliance, nanoparticles may represent ideal drug carriers for local therapeutics in psoriasis. In recent years, a series of reports added important insights into the biology of skin-nanoparticles interactions and on how they impact the epidermal and dermal inflammatory compartments in vitro and in psoriasis plaques. Furthermore, by targeting anti-inflammatory substances to specific skin compartments, nanotechnological advances offer the exciting opportunity to fine-tune skin inflammation at molecular and cellular levels, paving the road to a high-precision, skin-directed topical therapy in psoriasis. However, nanoparticle-based therapies have not yet found their way into clinical routine in dermatology. We here resume the current advances in the research of nanoparticles and skin inflammation in general and psoriasis in particular and discuss how this promising technology should develop in order to fulfil the requirements of an optimal skin therapy.

Topical silver and gold nanoparticles complexed with Cornus mas suppress inflammation in human psoriasis plaques by inhibiting NF-κB activity.

New biomaterials based on nanoparticles (NPs) carrying polyphenols-rich extracts (Cornus mas) recently showed promising anti-inflammatory activity in psoriasis. We aimed to understand how topically delivered silver and gold nanoparticles complexed with Cornus mas (Ag-NPs-CM, Au-NPs-CM) modulate inflammation in psoriasis at cellular and molecular level. The impact on psoriatic inflammation was assessed in vitro on pro-inflammatory macrophages, by clinical score, high-frequency ultrasonography and immunohistology of psoriasis plaques treated with Ag-NPs-CM, Au-NPs-CM or control. Incubation of pro-inflammatory macrophages with nanoparticles significantly decreased the release of NO, IL-12 and TNF-α. Immunofluorescence confirmed that nanoparticles significantly reduced CD68-positive macrophages and their IL-12 and TNF-α production in human psoriasis plaques. NPs-CM appear to repress NF-κB activation in macrophages, inhibiting the production of pro-inflammatory factors with causal role in psoriasis. Ag and Au NPs-CM represent a novel nanoparticle-based "green" technology which may provide an efficient tool for modern psoriasis therapy, circumventing immunosuppression-related side effects of biologicals.

Suppression of Neutrophil-Mediated Tissue Damage-A Novel Skill of Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) are crucial for tissue homeostasis and regeneration. Though of prime interest, their potentially protective role on neutrophil-induced tissue damage, associated with high morbidity and mortality, has not been explored in sufficient detail. Here we report the therapeutic skill of MSCs to suppress unrestrained neutrophil activation and to attenuate severe tissue damage in a murine immune-complex mediated vasculitis model of unbalanced neutrophil activation. MSC-mediated neutrophil suppression was due to intercellular adhesion molecule 1-dependent engulfment of neutrophils by MSCs, decreasing overall neutrophil numbers. Similar to MSCs in their endogenous niche of murine and human vasculitis, therapeutically injected MSCs via upregulation of the extracellular superoxide dismutase (SOD3), reduced superoxide anion concentrations and consequently prevented neutrophil death, neutrophil extracellular trap formation and spillage of matrix degrading neutrophil elastase, gelatinase and myeloperoxidase. SOD3-silenced MSCs did not exert tissue protective effects. Thus, MSCs hold substantial therapeutic promise to counteract tissue damage in conditions with unrestrained neutrophil activation. Stem Cells 2016;34:2393-2406.

Self-detection frequency and recognition patterns in medium to high-risk cutaneous melanoma patients.

BACKGROUND AND OBJECTIVES: The question of how frequently patients with medium to high-risk melanomas become aware of their tumors and which self-detection patterns exist remains unanswered. PATIENTS AND METHODS: We conducted a retrospective survey of melanoma patients who had undergone sentinel node biopsy between 2004 and 2008. One hundred twenty-seven out of a total of 133 patients completed the questionnaire. RESULTS: Twenty-five percent of patients had not noticed their tumors at all. The remaining 75 % showed three different self-detection patterns, with 25 % of individuals seeking medical advice within 0-12 weeks and another 25 % within 3-6 months. The remaining 25 % had waited for more than six months prior to tumor excision. Age, gender, and melanoma location were comparable in all self-detection subgroups. The most frequent subtypes were: SSM (59), NMM (31), ALM (9), UCM (9) and LMM (4). Rare subtypes occurred in 15 individuals. Patients with lesions previously noticed for 3-6 months revealed the highest average tumor thickness and the significantly highest number of pT4 tumors. Sixty percent of NMM patients had a disease history < 6 months. Rare subtypes such as amelanotic, spindle cell, or spitzoid melanoma were self-detected in only 50 % of cases. CONCLUSIONS: Even advanced melanoma lesions remained undetected in 25 % of patients; rare melanoma subtypes, in 50 % of cases. Thus, self-examination frequency, increased awareness of rare melanoma subtypes, and rapid referral to a specialist ought to be at the center of future awareness campaigns.

Häufigkeit und Muster der Tumorerkennung nach Selbstuntersuchung bei Mittel- bis Hochrisiko-Melanompatienten.

HINTERGRUND UND ZIELSETZUNG: Die Frage, wie oft Melanompatienten mit Mittel- bis Hochrisikomelanomen den Tumor bemerken und welche Eigenerkennungsmuster existieren ist bislang nicht beantwortet. PATIENTEN UND METHODEN: Wir haben eine retrospektive Studie an Melanompatienten durchgeführt, die sich zwischen 2004 und 2008 einer Sentinellymphknotenbiopsie unterzogen haben,. Der Fragebogen wurde von 127 der insgesamt 133 Patienten ausgefüllt. ERGEBNISSE: 25 % bemerkten den Tumor überhaupt nicht. Die restlichen 75 % zeigten verschiedene Eigenerkennungsmuster: 25 % holten nach 0-12 Wochen Rat ein, weitere 25 % innerhalb von 3-6 Monaten, und bei den restlichen 25 % wurde der Tumor mehr als sechs Monate lang beobachtet, bevor er entfernt wurde. Alter, Geschlecht und Lokalisation des Melanoms waren bei allen Eigenerkennungsgruppen vergleichbar. Die häufigsten Subtypen waren: SSM (59), NMM (31), ALM (9), UCM (9) und LMM (4). Seltene Subtypen (15) waren ebenfalls vorhanden. Patienten mit 3-6 Monate alten Läsionen zeigten die höchste durchschnittliche Tumordicke und die bei weitem höchste Anzahl von pT4-Tumoren. 60 % der Patienten mit NMM hatten eine Krankengeschichte von <6 Monaten. Seltene Subtypen wie amelanotische, Spindelzell- und spitzoide Melanome wurden in nur 50 % der Fälle selbstständig erkannt. SCHLUSSFOLGERUNGEN: Selbst fortgeschrittene Melanome blieben von den Patienten in 25 %, seltene Melanom-Subtypen in 50 % der Fälle unerkannt. Daher sollte der Eigenerkennungshäufigkeit, dem erhöhten Bewusstsein für seltene Melanome und der schnellen Überweisung an einen Spezialisten in zukünftigen Aufklärungskampagnen besondere Aufmerksamkeit zukommen.

Reduced CD18 levels drive regulatory T cell conversion into Th17 cells in the CD18hypo PL/J mouse model of psoriasis.

Defective development and function of CD4(+)CD25(high+)Foxp3(+) regulatory T cells (Tregs) contribute to the pathogenesis of psoriasis and other autoimmune diseases. Little is known about the influence of adhesions molecules on the differentiation of Foxp3(+) Tregs into proinflammatory Th17 cells occurring in lesional skin and blood of psoriasis patients. In the CD18(hypo) PL/J mouse model of psoriasis, reduced expression of CD18/ß2 integrin to 2-16% of wild-type levels is associated with progressive loss of Tregs, impaired cell-cell contact between Tregs and dendritic cells (DCs), as well as Treg dysfunction as reported earlier. In the present investigation, Tregs derived from CD18(hypo) PL/J mice were analyzed for their propensity to differentiate into IL-17-producing Th17 cells in vivo and in in vitro Treg-DC cocultures. Adoptively transferred CD18(hypo) PL/J Tregs were more inclined toward conversion into IL-17-producing Th17 cells in vivo in an inflammatory as well as noninflammatory environment compared with CD18(wt) PL/J Tregs. Addition of neutralizing Ab against CD18 to Treg-DC cocultures in vitro promoted conversion of CD18(wt) PL/J Tregs to Th17 cells in a dose-dependent manner similar to conversion rates of CD18(hypo) PL/J Tregs. Reduced thymic output of naturally occurring Tregs and peripheral conversion of Tregs into Th17 cells therefore both contribute to the loss of Tregs and the psoriasiform dermatitis observed in CD18(hypo) PL/J mice. Our data overall indicate that CD18 expression levels impact Treg development as well as Treg plasticity and that differentiation of Tregs into IL-17-producing Th17 cells is distinctly facilitated by a subtotal deficiency of CD18.

Tropisetron suppresses collagen synthesis in skin fibroblasts via α7 nicotinic acetylcholine receptor and attenuates fibrosis in a scleroderma mouse model.

OBJECTIVE: There is increasing evidence that serotonin (5-hydroxytryptamine [5-HT]) and distinct 5-HT receptors are involved in the pathogenesis of systemic sclerosis. The aim of this study was to test the hypothesis that tropisetron, a routinely used antiemetic agent previously characterized as a 5-HT(3/4) receptor-modulating agent, can directly affect collagen synthesis in vitro and attenuate experimentally induced fibrosis in vivo. METHODS: Functional in vitro studies were performed using human dermal fibroblasts (HDFs). Signal transduction studies included immunofluorescence analysis, Western immunoblotting, promoter reporter assays, cAMP/Ca(2+) measurements, and use of pharmacologic activators and inhibitors. Gene silencing was performed using small interfering RNA. Putative receptors of tropisetron were detected by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence. The murine model of bleomycin-induced scleroderma was used to assess the antifibrogenic and antifibrotic effects of tropisetron in vivo. Collagen expression in vitro, ex vivo, and in situ was determined by real-time RT-PCR analysis, Western immunoblotting, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunohistochemical analysis. RESULTS: Tropisetron suppressed collagen synthesis induced by transforming growth factor ß1 (TGFß1). This effect was independent of 5-HT(3/4) receptor but was mediated via α7 nicotinic acetylcholine receptor (α7nAChR). Suppression of TGFß1-induced collagen synthesis occurred via an unknown molecular mechanism not involving modulation of the Smad, cAMP, Akt, c-Jun, or MAPK pathway. In vivo, tropisetron not only prevented skin fibrosis but also reduced the collagen content in established dermal fibrosis induced by bleomycin. CONCLUSION: Tropisetron directly reduces collagen synthesis in HDFs via an α7nAChR-dependent mechanism. The antifibrogenic and antifibrotic effects of this agent observed in a mouse model of bleomycin- induced scleroderma indicate the future potential of tropisetron in the treatment of fibrotic diseases such as scleroderma.

Hepatic activation of IKK/NFκB signaling induces liver fibrosis via macrophage-mediated chronic inflammation.

UNLABELLED: Liver damage in humans is induced by various insults including alcohol abuse, hepatitis B/C virus infection, autoimmune or metabolic disorders and, when persistent, leads to development of liver fibrosis. Because the nuclear factor-κB (NF-κB) system is activated in response to several of these stresses, we hypothesized that NF-κB activation in hepatocytes may contribute to fibrosis development. To activate the NF-κB signaling pathway in a time- and cell-type-specific manner in the liver, we crossed transgenic mice carrying the tetracycline-responsive transactivator under the control of the liver activator protein promotor with transgenic mice carrying a constitutively active form of the Ikbkb gene (IKK2 protein [CAIKK2]). Double-transgenic mice displayed doxycycline-regulated CAIKK2 expression in hepatocytes. Removal of doxycycline at birth led to activation of NF-κB signaling, moderate liver damage, recruitment of inflammatory cells, hepatocyte proliferation, and ultimately to spontaneous liver fibrosis development. Microarray analysis revealed prominent up-regulation of chemokines and chemokine receptors and this induction was rapidly reversed after switching off the CAIKK2 expression. Turning off the transgene expression for 3 weeks reversed stellate cell activation but did not diminish liver fibrosis. The elimination of macrophages by clodronate-liposomes attenuated NF-κB-induced liver fibrosis in a liver-injury-independent manner. CONCLUSION: Our results revealed that hepatic activation of IKK/NF-κB is sufficient to induce liver fibrosis by way of macrophage-mediated chronic inflammation. Therefore, agents controlling the hepatic NF-κB system represent attractive therapeutic tools to prevent fibrosis development in multiple chronic liver diseases.

Neutrophil development and function critically depend on Bruton tyrosine kinase in a mouse model of X-linked agammaglobulinemia.

Bruton tyrosine kinase (Btk) is essential for B cell development and function and also appears to be important for myeloid cells. The bone marrow of Btk-deficient mice shows enhanced granulopoiesis compared with that of wild-type mice. In purified granulocyte-monocyte-progenitors (GMP) from Btk-deficient mice, the development of granulocytes is favored at the expense of monocytes. However, Btk-deficient neutrophils are impaired in maturation and function. Using bone marrow chimeras, we show that this defect is cell-intrinsic to neutrophils. In GMP and neutrophils, Btk plays a role in GM-CSF- and Toll-like receptor-induced differentiation. Molecular analyses revealed that expression of the lineage-determining transcription factors C/EBPα, C/EBPß, and PU.1, depends on Btk. In addition, expression of several granule proteins, including myeloperoxidase, neutrophilic granule protein, gelatinase and neutrophil elastase, is Btk-dependent. In the Arthus reaction, an acute inflammatory response, neutrophil migration into tissues, edema formation, and hemorrhage are significantly reduced in Btk-deficient animals. Together, our findings implicate Btk as an important regulator of neutrophilic granulocyte maturation and function in vivo.

Class IA phosphoinositide 3-kinase ß and δ regulate neutrophil oxidase activation in response to Aspergillus fumigatus hyphae.

An effective immune response to the ubiquitous fungus Aspergillus fumigatus is dependent upon production of reactive oxygen species (ROS) by the NADPH oxidase. This is evidenced by the acute sensitivity of oxidase-deficient humans and mice to invasive aspergillosis. Neutrophils are recruited to the lungs shortly postinfection and respond by phagocytosing conidia and mediating extracellular killing of germinated hyphae in a ROS-dependent manner. However, the signaling mechanisms regulating the generation of ROS in response to hyphae are poorly understood. PI3Ks are important regulators of numerous cellular processes, with much recent work describing unique roles for the different class I PI3K isoforms. We showed by live-cell imaging that the lipid products of class I PI3Ks accumulated at the hyphal-bound neutrophil plasma membrane. Further, we used pharmacological and genetic approaches to demonstrate essential, but overlapping, roles for PI3Kß and PI3Kδ in the ROS and spreading responses of murine neutrophils to Aspergillus hyphae. Hyphal-induced ROS responses were substantially inhibited by deletion of the common ß2-integrin subunit CD18, with only a minor, redundant role for Dectin-1. However, addition of soluble algal glucans plus the genetic deletion of CD18 were required to significantly inhibit activation of the PI3K-effector protein kinase B. Hyphal ROS responses were also totally dependent on the presence of Syk, but not its ITAM-containing adaptor proteins FcRγ or DAP12, and the Vav family of Rac-guanine nucleotide exchange factors. These results start to define the signaling network controlling neutrophil ROS responses to A. fumigatus hyphae.