Author Correction: A Novel S100A8/A9 Induced Fingerprint of Mesenchymal Stem Cells associated with Enhanced Wound Healing.

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A Novel S100A8/A9 Induced Fingerprint of Mesenchymal Stem Cells associated with Enhanced Wound Healing.

We here investigated whether the unique capacity of mesenchymal stem cells (MSCs) to re-establish tissue homeostasis depends on their potential to sense danger associated molecular pattern (DAMP) and to mount an adaptive response in the interest of tissue repair. Unexpectedly, after injection of MSCs which had been pretreated with the calcium-binding DAMP protein S100A8/A9 into murine full-thickness wounds, we observed a significant acceleration of healing even exceeding that of non-treated MSCs. This correlates with a fundamental reprogramming of the transcriptome in S100A8/A9 treated MSCs as deduced from RNA-seq analysis and its validation. A network of genes involved in proteolysis, macrophage phagocytosis, and inflammation control profoundly contribute to the clean-up of the wound site. In parallel, miR582-5p and genes boosting energy and encoding specific extracellular matrix proteins are reminiscent of scar-reduced tissue repair. This unprecedented finding holds substantial promise to refine current MSC-based therapies for difficult-to-treat wounds and fibrotic conditions.

ATM is required for SOD2 expression and homeostasis within the mammary gland.

PURPOSE: ATM activates the NF-κB transcriptional complex in response to genotoxic and oxidative stress. The purpose of this study was to examine if the NF-κB target gene and critical antioxidant SOD2 (MnSOD) in cultured mammary epithelium is also ATM-dependent, and what phenotypes arise from deletion of ATM and SOD2 within the mammary gland. METHODS: SOD2 expression was studied in human mammary epithelial cells and MCF10A using RNAi to knockdown ATM or the NF-κB subunit RelA. To study ATM and SOD2 function in mammary glands, mouse lines containing Atm or Sod2 genes containing LoxP sites were mated with mice harboring Cre recombinase under the control of the whey acidic protein promoter. Quantitative PCR was used to measure gene expression, and mammary gland structure was studied using histology. RESULTS: SOD2 expression is ATM- and RelA-dependent, ATM knockdown renders cells sensitive to pro-oxidant exposure, and SOD mimetics partially rescue this sensitivity. Mice with germline deletion of Atm fail to develop mature mammary glands, but using a conditional knockout approach, we determined that Atm deletion significantly diminished the expression of Sod2. We also observed that these mice (termed AtmΔ/Δ) displayed a progressive lactation defect as judged by reduced pup growth rate, aberrant lobulo-alveolar structure, diminished milk protein gene expression, and increased apoptosis within lactating glands. This phenotype appears to be linked to dysregulated Sod2 expression as mammary gland-specific deletion of Sod2 phenocopies defects observed in AtmΔ/Δ dams. CONCLUSIONS: We conclude that ATM is required to promote expression of SOD2 within the mammary epithelium, and that both ATM and SOD2 play a crucial role in mammary gland homeostasis.

Alpha-Ketoglutarate Curbs Differentiation and Induces Cell Death in Mesenchymal Stromal Precursors with Mitochondrial Dysfunction.

Increased concentrations of reactive oxygen species (ROS) originating from dysfunctional mitochondria contribute to diverse aging-related degenerative disorders. But so far little is known about the impact of distinct ROS on metabolism and fate of stromal precursor cells. Here, we demonstrate that an increase in superoxide anion radicals due to superoxide dismutase 2 (Sod2) deficiency in stromal precursor cells suppress osteogenic and adipogenic differentiation through fundamental changes in the global metabolite landscape. Our data identify impairment of the pyruvate and l-glutamine metabolism causing toxic accumulation of alpha-ketoglutarate in the Sod2-deficient and intrinsically aged stromal precursor cells as a major cause for their reduced lineage differentiation. Alpha-ketoglutarate accumulation led to enhanced nucleocytoplasmic vacuolation and chromatin condensation-mediated cell death in Sod2-deficient stromal precursor cells as a consequence of DNA damage, Hif-1α instability, and reduced histone H3 (Lys27) acetylation. These findings hold promise for prevention and treatment of mitochondrial disorders commonly associated with aged individuals. Stem Cells 2017;35:1704-1718.

Checkpoint inhibition for advanced mucosal melanoma.

BACKGROUND: Whereas anti-PD-1 therapy has demonstrated a significant and durable response against advanced cutaneous melanoma, conventional chemotherapies have shown only minor benefit against advanced mucosal melanoma. OBJECTIVES: To investigate the efficacy of anti-PD-1 therapy in a small cohort of patients with mucosal melanoma of the head and neck. MATERIALS & METHODS: We analysed five patients with mucosal melanoma of the head and neck who received nivolumab or pembrolizumab, at an advanced stage. Expression of PD-L1 and PD-1 in all tumour samples was evaluated immunohistochemically. RESULTS: All patients received at least two cycles of nivolumab or pembrolizumab. The most severe adverse events were categorised as CTCAE (common terminology criteria for adverse events) Grade 2. All patients showed progressive disease after restaging at three and six months, and no partial or complete response was observed. Immunohistochemical staining demonstrated PD-L1 expression in less than 5% of tumour cells. CONCLUSION: Systemic therapy with either nivolumab or pembrolizumab showed no clinical response, however, tumour progression was identified in all patients using Response Evaluation Criteria In Solid Tumors (RECIST) v1.1 and immune-related response criteria (irRC) to evaluate tumour response.

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.

Senescent fibroblast-derived Chemerin promotes squamous cell carcinoma migration.

Aging is associated with a rising incidence of cutaneous squamous cell carcinoma (cSCC), an aggressive skin cancer with the potential for local invasion and metastasis. Acquisition of a senescence-associated secretory phenotype (SASP) in dermal fibroblasts has been postulated to promote skin cancer progression in elderly individuals. The underlying molecular mechanisms are largely unexplored. We show that Chemerin, a previously unreported SASP factor released from senescent human dermal fibroblasts, promotes cSCC cell migration, a key feature driving tumor progression. Whereas the Chemerin abundance is downregulated in malignant cSCC cells, increased Chemerin transcripts and protein concentrations are detected in replicative senescent fibroblasts in vitro and in the fibroblast of skin sections from old donors, indicating that a Chemerin gradient is built up in the dermis of elderly. Using Transwell® migration assays, we show that Chemerin enhances the chemotaxis of different cSCC cell lines. Notably, the Chemerin receptor CCRL2 is remarkably upregulated in cSCC cell lines and human patient biopsies. Silencing Chemerin in senescent fibroblasts or the CCRL2 and GPR1 receptors in the SCL-1 cSCC cell line abrogates the Chemerin-mediated chemotaxis. Chemerin triggers the MAPK cascade via JNK and ERK1 activation, whereby the inhibition impairs the SASP- or Chemerin-mediated cSCC cell migration.Taken together, we uncover a key role for Chemerin, as a major factor in the secretome of senescent fibroblasts, promoting cSCC cell migration and possibly progression, relaying its signals through CCRL2 and GPR1 receptors with subsequent MAPK activation. These findings might have implications for targeted therapeutic interventions in elderly patients.

Chirurgische Behandlung von Melanomen in der Schwangerschaft: eine praktische Anleitung.

Als ein Tumor, der primär eine chirurgische Behandlung erfordert, ist ein neu diagnostiziertes oder vorbestehendes Melanom in der Schwangerschaft eine klinische Rarität. In solchen Fällen steht der Chirurg vor der Herausforderung, ein geeignetes therapeutisches Vorgehen festlegen zu müssen. Auf der Grundlage unserer klinischen Erfahrung und einer Übersicht über die Literatur geben wir in der vorliegenden Arbeit eine Anleitung für das praktische Vorgehen bei dieser seltenen klinischen Konstellation. Unserer Erfahrung nach müssen schwangere Melanom-Patientinnen im Hinblick auf ihre therapeutischen Optionen ausführlich beraten werden. Naturgemäß setzen sie ihr ungeborenes Kind an die erste Stelle und zögern, der erforderlichen Operation zuzustimmen, obwohl bei ihnen eine möglicherweise lebensbedrohliche Erkrankung diagnostiziert worden ist. Daher ist es entscheidend, diese Patientinnen klar darüber zu informieren, dass, wie die vorliegenden medizinischen Erfahrungen zeigen, eine Schwangerschaft per se kein Grund ist, eine notwendige Melanom-Operation aufzuschieben. Jedoch müssen bei einigen Parametern wie den präoperativen Bildgebungsverfahren, der Positionierung auf dem Operationstisch, der Überwachung, Anästhesie und der perioperativen Medikation bestimmte Anpassungen vorgenommen werden, um der speziellen Situation Rechnung zu tragen.

Surgical treatment of melanoma in pregnancy: a practical guideline.

A tumor primarily requiring surgical treatment, newly diagnosed or preexisting melanoma during pregnancy is a clinical rarity. In such cases, the surgeon faces the challenge of having to decide on the appropriate therapeutic course of action. Based on our clinical experience and a review of the literature, we herein provide a guideline on how to practically deal with this rare clinical conundrum. In our experience, pregnant melanoma patients require thorough counseling with respect to their therapeutic options. They naturally tend to put their unborn child first, and are hesitant to consent to necessary surgery despite a potentially life-threatening diagnosis. It is therefore crucial to clearly inform these patients that - based on existing medical experience - pregnancy by itself is no reason to hold off on any type of necessary melanoma surgery. However, various parameters such as preoperative imaging procedures, positioning on the operating table, monitoring, anesthesia, and perioperative medication require certain adjustments in order to comply with this special situation.

Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN.

The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions (O2∙-) in mitochondria, either by chemical inhibition of complex I or by genetic silencing of O2∙--dismutating mitochondrial Sod2. The O2∙--dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of α1(I), α1(III), and α2(I) collagen, the hallmarks of skin ageing. Enhanced O2∙- led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated O2∙--induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with O2∙-, PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies.

TSG-6 released from intradermally injected mesenchymal stem cells accelerates wound healing and reduces tissue fibrosis in murine full-thickness skin wounds.

Proper activation of macrophages (Mφ) in the inflammatory phase of acute wound healing is essential for physiological tissue repair. However, there is a strong indication that robust Mφ inflammatory responses may be causal for the fibrotic response always accompanying adult wound healing. Using a complementary approach of in vitro and in vivo studies, we here addressed the question of whether mesenchymal stem cells (MSCs)-due to their anti-inflammatory properties-would control Mφ activation and tissue fibrosis in a murine model of full-thickness skin wounds. We have shown that the tumor necrosis factor-α (TNF-α)-stimulated protein 6 (TSG-6) released from MSCs in co-culture with activated Mφ or following injection into wound margins suppressed the release of TNF-α from activated Mφ and concomitantly induced a switch from a high to an anti-fibrotic low transforming growth factor-ß1 (TGF-ß1)/TGF-ß3 ratio. This study provides insight into what we believe to be a previously undescribed multifaceted role of MSC-released TSG-6 in wound healing. MSC-released TSG-6 was identified to improve wound healing by limiting Mφ activation, inflammation, and fibrosis. TSG-6 and MSC-based therapies may thus qualify as promising strategies to enhance tissue repair and to prevent excessive tissue fibrosis.

Molecular mechanisms of the crosstalk between mitochondria and NADPH oxidase through reactive oxygen species-studies in white blood cells and in animal models.

AIMS: Oxidative stress is involved in the development of cardiovascular disease. There is a growing body of evidence for a crosstalk between different enzymatic sources of oxidative stress. With the present study, we sought to determine the underlying crosstalk mechanisms, the role of the mitochondrial permeability transition pore (mPTP), and its link to endothelial dysfunction. RESULTS: NADPH oxidase (Nox) activation (oxidative burst and translocation of cytosolic Nox subunits) was observed in response to mitochondrial reactive oxygen species (mtROS) formation in human leukocytes. In vitro, mtROS-induced Nox activation was prevented by inhibitors of the mPTP, protein kinase C, tyrosine kinase cSrc, Nox itself, or an intracellular calcium chelator and was absent in leukocytes with p47phox deficiency (regulates Nox2) or with cyclophilin D deficiency (regulates mPTP). In contrast, the crosstalk in leukocytes was amplified by mitochondrial superoxide dismutase (type 2) (MnSOD(+/-)) deficiency. In vivo, increases in blood pressure, degree of endothelial dysfunction, endothelial nitric oxide synthase (eNOS) dysregulation/uncoupling (e.g., eNOS S-glutathionylation) or Nox activity, p47phox phosphorylation in response to angiotensin-II (AT-II) in vivo treatment, or the aging process were more pronounced in MnSOD(+/-) mice as compared with untreated controls and improved by mPTP inhibition by cyclophilin D deficiency or sanglifehrin A therapy. INNOVATION: These results provide new mechanistic insights into what extent mtROS trigger Nox activation in phagocytes and cardiovascular tissue, leading to endothelial dysfunction. CONCLUSIONS: Our data show that mtROS trigger the activation of phagocytic and cardiovascular NADPH oxidases, which may have fundamental implications for immune cell activation and development of AT-II-induced hypertension.

The role of manganese superoxide dismutase in skin aging.

The free radical theory of aging postulates that the production of mitochondrial reactive oxygen species is the major determinant of aging and lifespan. The skin represents an excellent and accessible model organ to study aging that is characterized by atrophy, wrinkle formation, reduced tensile strength and impaired wound healing. Oxidative stress as a consequence of an imbalance in prooxidants and antioxidants with increased ROS concentrations has been demonstrated in the aged skin in vitro and in vivo, suggesting the important role of the antioxidant balance. Here we will summarize recent data on the role of the mitochondrial superoxide dismutase 2 in skin aging.

Effect of exercise on bone and articular cartilage in heterozygous manganese superoxide dismutase (SOD2) deficient mice.

Reactive oxygen species (ROS) are involved in both bone and cartilage physiology and play an important role in the pathogenesis of osteoporosis and osteoarthritis. The present study investigated the effect of running exercise on bone and cartilage in heterozygous manganese superoxide dismutase (SOD2)-deficient mice. It was hypothesized that exercise might induce an increased production of ROS in these tissues. Heterozygous SOD2-deficient mice should exhibit an impaired capability to compensate, resulting in an increased oxidative stress in cartilage and bone. Thirteen female wild type and 20 SOD2(+/-) mice (aged 16 weeks) were randomly assigned to a non-active wild type (SOD2(+/+)Con, n = 7), a trained wild type (SOD2(+/+)Run, n = 6), a non-active SOD2(+/-) (SOD2(+/-)Con, n = 9) and a trained SOD2(+/-) (SOD2(+/-)Run, n = 11) group. Training groups underwent running exercise on a treadmill for 8 weeks. In SOD2(+/-) mice elevated levels of 15-F(2t)-isoprostane and nitrotyrosine were detected in bone and articular cartilage compared to wild type littermates. In osteocytes the elevated levels of these molecules were found to be reduced after exercise while in chondrocytes they were increased by aerobic running exercise. The observed changes in oxidative and nitrosative stress did neither affect morphological, structural nor mechanical properties of both tissues. These results demonstrate that exercise might protect bone against oxidative stress in heterozygous SOD2-deficient mice.

Accelerated aging phenotype in mice with conditional deficiency for mitochondrial superoxide dismutase in the connective tissue.

The free radical theory of aging postulates that the production of mitochondrial reactive oxygen species is the major determinant of aging and lifespan. Its role in aging of the connective tissue has not yet been established, even though the incidence of aging-related disorders in connective tissue-rich organs is high, causing major disability in the elderly. We have now addressed this question experimentally by creating mice with conditional deficiency of the mitochondrial manganese superoxide dismutase in fibroblasts and other mesenchyme-derived cells of connective tissues in all organs. Here, we have shown for the first time that the connective tissue-specific lack of superoxide anion detoxification in the mitochondria results in reduced lifespan and premature onset of aging-related phenotypes such as weight loss, skin atrophy, kyphosis (curvature of the spine), osteoporosis and muscle degeneration in mutant mice. Increase in p16(INK4a) , a robust in vivo marker for fibroblast aging, may contribute to the observed phenotype. This novel model is particularly suited to decipher the underlying mechanisms and to develop hopefully novel connective tissue-specific anti-aging strategies.