Effects of sulfur mustard on mesenchymal stem cells

Sulfur mustard single-dose exposure triggers senescence in primary human dermal fibroblasts

Chronic wounds, skin blisters, and ulcers are the result of skin exposure to the alkylating agent sulfur mustard (SM). One potential pathomechanism is senescence, which causes permanent growth arrest with a pro-inflammatory environment and may be associated with a chronic wound healing disorder. SM is known to induce chronic senescence in human mesenchymal stem cells which are subsequently unable to fulfill their regenerative function in the wound healing process. As dermal fibroblasts are crucial for cutaneous wound healing by being responsible for granulation tissue formation and synthesis of the extracellular matrix, SM exposure might also impair their function in a similar way. This study, therefore, investigated the SM sensitivity of primary human dermal fibroblasts (HDF) by determining the dose-response curve. Non-lethal concentrations LC₁ (3 µM) to LC₂₅ (65 µM) were used to examine the induction of senescence. HDF were exposed once to 3 µM, 13 µM, 24 µM, 40 µM or 65 μM SM, and were then cultured for 31 days. Changes in morphology as well as at the genetic and protein level were investigated. For the first time, HDF were shown to undergo senescence in a time- and concentration-dependent manner after SM exposure. They developed a characteristic senescence phenotype and expressed various senescence markers. Proinflammatory cytokines and chemokines were significantly altered in SM-exposed HDF as part of a senescence-associated secretory phenotype. The senescent fibroblasts can thus be considered a contributor to the SM-induced chronic wound healing disorder and might serve as a new therapeutic target in the future.

Chemogenetic biocompatibly of mercury as specific hypercalcemia actuator in neuronal spinal cord cell manipulation: Zeta bio-sensing analysis

Chemogenetic property of mercuric ion (Hg²⁺) was investigated as a specific hypercalcemia actuator in the neuronal spinal cord cell manipulation by Zeta-based potentiometric bio-sensing analysis via introducing a novel array-based Hg²⁺ bio-sensor. For this purpose, the array of a two-electrode system including Ag/AgCl (sat'd Cl^-) as reference electrode and a paste nano-composite as the indicator electrode was utilized. The indicator electrode was made of activated multi-walled carbon nanotubes as conductive support, a grounded slice of sheep's spinal cord as natural neuron stem cells (ionophore), and oxalate ion as both the dispersed phase and cationic site. Under optimum conditions by one-at-a-time method, a two-linear range between 1.3 × 10^-4- 6.5 × 10^-12 and 2.7 × 10^-14- 1.4 × 10^-21 mol L^-1 with correlation coefficients (R²) of 0.96 and 0.99, respectively, and response time (t₉₀) of maximum 5.0 min were approximated. The percentages of relative standard deviation were estimated to be 4.05 (repeatability, n = 10) and 6.14 (reproducibility, n = 12). The detection limit was estimated to be sub 5.3 × 10^-22 mol L^-1 based on the X̄_b+3S_b. The reliability of this phenomenon was evidenced by different analytical techniques. The Zeta-based electrical response was therefore attributed to highly Ca²⁺ pumping from the stem cells ionic channel gates as the proposed mechanistic behavior of the spinal cord. Actuating (triggering) the stem cells by Hg²⁺ consequently led to generate significant Zeta potential as the proposed mechanism. The results pointed to the potentiometric responsibility of a protein with gram molecular weight of 66.2 ± 0.3 KCU in the stem cell matrix as a specific hypercalcemia actuator.

Current Advanced Therapies Based on Human Mesenchymal Stem Cells for Skin Diseases

Skin disease may be related with immunological disorders, external aggressions, or genetic conditions. Injuries or cutaneous diseases such as wounds, burns, psoriasis, and scleroderma among others are common pathologies in dermatology, and in some cases, conventional treatments are ineffective. In recent years, advanced therapies using human mesenchymal stem cells (hMSCs) from different sources has emerged as a promising strategy for the treatment of many pathologies. Due to their properties; regenerative, immunomodulatory and differentiation capacities, they could be applied for the treatment of cutaneous diseases. In this review, a total of thirteen types of hMSCs used as advanced therapy have been analyzed, considering the last 5 years (2015-2020). The most investigated types were those isolated from umbilical cord blood (hUCB-MSCs), adipose tissue (hAT-MSCs) and bone marrow (hBM-MSCs). The most studied diseases were wounds and ulcers, burns and psoriasis. At preclinical level, in vivo studies with mice and rats were the main animal models used, and a wide range of types of hMSCs were used. Clinical studies analyzed revealed that cell therapy by intravenous administration was the advanced therapy preferred except in the case of wounds and burns where tissue engineering was also reported. Although in most of the clinical trials reviewed results have not been posted yet, safety was high and only local slight adverse events (mild nausea or abdominal pain) were reported. In terms of effectiveness, it was difficult to compare the results due to the different doses administered and variables measured, but in general, percentage of wound's size reduction was higher than 80% in wounds, Psoriasis Area and Severity Index and Severity Scoring for Atopic Dermatitis were significantly reduced, for scleroderma, parameters such as Modified Rodnan skin score (MRSC) or European Scleroderma Study Group activity index reported an improvement of the disease and for hypertrophic scars, Vancouver Scar Scale (VSS) score was decreased after applying these therapies. On balance, hMSCs used for the treatment of cutaneous diseases is a promising strategy, however, the different experimental designs and endpoints stablished in each study, makes necessary more research to find the best way to treat each patient and disease.

Chronic senescent human mesenchymal stem cells as possible contributor to the wound healing disorder after exposure to the alkylating agent sulfur mustard

Wound healing is a complex process, and disturbance of even a single mechanism can result in chronic ulcers developing after exposure to the alkylating agent sulfur mustard (SM). A possible contributor may be SM-induced chronic senescent mesenchymal stem cells (MSCs), unable to fulfil their regenerative role, by persisting over long time periods and creating a proinflammatory microenvironment. Here we show that senescence induction in human bone marrow derived MSCs was time- and concentration-dependent, and chronic senescence could be verified 3 weeks after exposure to between 10 and 40 µM SM. Morphological changes, reduced clonogenic and migration potential, longer scratch closure times, differences in senescence, motility and DNA damage response associated genes as well as increased levels of proinflammatory cytokines were revealed. Selective removal of these cells by senolytic drugs, in which ABT-263 showed initial potential in vitro, opens the possibility for an innovative treatment strategy for chronic wounds, but also tumors and age-related diseases.

Impairment of endothelial progenitor cells function in patient with mustard gas intoxication

Background: Sulfur mustard (SM), also known as mustard gas, was first widely used in the Iraq-Iran. After SM exposure, the most prominent clinical signs are the development of extensive non-healing skin wounds and pulmonary signs, persisting over long time. Since the most frequent complications in SM-intoxicated patients are respiratory and dermatologic lesions, and with respect to the important role of endothelial progenitor cells (EPCs) in the pathophysiology of these lesion, we conducted this study to recognize the potential effects of SM on biological features of EPCs in patients exposed with this gas.Methods: In this study, 30 patients with the history of SM exposure during the Iran-Iraq war (1984-1988), 27 patients with pulmonary signs with no history of SM exposure and 20 healthy participants were included. Cell population and function of EPCs were assessed 4 years post-exposure. For this purpose, circulating EPCs (cEPCs) were harvested and cultivated, then the biological features of these cells, including migratory, proliferative, and tubulogenic activities were analyzed. We also measured serum antioxidants levels and mRNA levels of some proangiogenic factors in EPCs from SM-intoxicated patients.Results: Our results showed lesser number of cEPCs in patients exposed with SM, which was associated with decreased proliferative, migratory, and tubulogenic activity of these cells. Also, we found the lesser serum activity of SOD, GPX and MDA in the SM group than in the healthy control group.Conclusions: SM exposure resulted in decreased proliferation and migration of EPCs, which was associated with decreased tubule formation and angiogenic factors.

Brain-Derived Neurotrophin and TrkB in Head and Neck Squamous Cell Carcinoma

We hypothesized that in head and neck squamous cell carcinoma (HNSCC), the neurotrophin brain-derived neurotrophic factor (BDNF) and its high affinity receptor TrkB regulate tumor cell survival, invasion, and therapy resistance. We used in situ hybridization for BDNF and immunohistochemistry (IHC) for TrkB in 131 HNSCC samples. Brain-derived neurotrophic factor was highly expressed in normal mucosa in HNSCC tissue and in cell lines, whereas only 42.74% of HNSCC tissue was TrkB⁺. One fourth of HNSCC cases was human papilloma virus (HPV)⁻ positive, but the TrkB IHC frequency was not different in HPV-positive (HPV⁺) and negative cases. The UPCI-SCC090 cells expressed constitutive levels of TrkB. Transforming-growth-factor-β1 (1 ng/mL TGF-β1) induced TrkB in a subpopulation of SCC-25 cells. A single 10-µg/mL mitomycin C treatment in UPCI-SCC090 cells induced apoptosis and BDNF did not rescue them. The SCC-25 cells were resistant to the MMC treatment, and their growth decreased after TGF-β1 treatment, but was restored by BDNF if it followed TGF-β1. Taken together, BDNF might be ineffective in HPV⁺ HNSCC patients. In HPV⁻ HNSCC patients, tumor cells did not die after chemotherapeutic challenge and BDNF with TGF-β1 could improve tumor cell survival and contribute to worse patient prognosis.