Argelia Lopez

A Synthetic Superoxide Dismutase/Catalase Mimetic EUK-207 Mitigates Radiation Dermatitis and Promotes Wound Healing in Irradiated Rat Skin.

In the event of a radionuclear attack or nuclear accident, the skin would be the first barrier exposed to radiation, though skin injury can progress over days to years following exposure. Chronic oxidative stress has been implicated as being a potential contributor to the progression of delayed radiation-induced injury to skin and other organs. To examine the causative role of oxidative stress in delayed radiation-induced skin injury, including impaired wound healing, we tested a synthetic superoxide dismutase (SOD)/catalase mimetic, EUK-207, in a rat model of combined skin irradiation and wound injury. Administered systemically, beginning 48 h after irradiation, EUK-207 mitigated radiation dermatitis, suppressed indicators of tissue oxidative stress, and enhanced wound healing. Evaluation of gene expression in irradiated skin at 30 days after exposure revealed a significant upregulation of several key genes involved in detoxication of reactive oxygen and nitrogen species. This gene expression pattern was primarily reversed by EUK-207 therapy. These results demonstrate that oxidative stress plays a critical role in the progression of radiation-induced skin injury, and that the injury can be mitigated by appropriate antioxidant compounds administered 48 h after exposure.

Laminin 332 Deposition is Diminished in Irradiated Skin in an Animal Model of Combined Radiation and Wound Skin Injury

Skin exposure to ionizing radiation affects the normal wound healing process and greatly impacts the prognosis of affected individuals. We investigated the effect of ionizing radiation on wound healing in a rat model of combined radiation and wound skin injury. Using a soft X-ray beam, a single dose of ionizing radiation (10–40 Gy) was delivered to the skin without significant exposure to internal organs. At 1 h postirradiation, two skin wounds were made on the back of each rat. Control and experimental animals were euthanized at 3, 7, 14, 21 and 30 days postirradiation. The wound areas were measured, and tissue samples were evaluated for laminin 332 and matrix metalloproteinase (MMP) 2 expression. Our results clearly demonstrate that radiation exposure significantly delayed wound healing in a dose-related manner. Evaluation of irradiated and wounded skin showed decreased deposition of laminin 332 protein in the epidermal basement membrane together with an elevated expression of all three laminin 332 genes within 3 days postirradiation. The elevated laminin 332 gene expression was paralleled by an elevated gene and protein expression of MMP2, suggesting that the reduced amount of laminin 332 in irradiated skin is due to an imbalance between laminin 332 secretion and its accelerated processing by elevated tissue metalloproteinases. Western blot analysis of cultured rat keratinocytes showed decreased laminin 332 deposition by irradiated cells, and incubation of irradiated keratinocytes with MMP inhibitor significantly increased the amount of deposited laminin 332. Furthermore, irradiated keratinocytes exhibited a longer time to close an artificial wound, and this delay was partially corrected by seeding keratinocytes on laminin 332-coated plates. These data strongly suggest that laminin 332 deposition is inhibited by ionizing radiation and, in combination with slower keratinocyte migration, can contribute to the delayed wound healing of irradiated skin.

D - Penicillamine-induced pemphigus foliaceus with autoantibodies to desmoglein-1 in a patient with mixed connective tissue disease

Pemphigus is a bullous disease characterized by antidesmoglein autoantibodies. Desmogleins are members of the cadherin family of Ca++-depen dent cell adhesion molecules. Cadherins are subdivided into the classic and desmosomal cadherins. Desmogleins and desmocollins belong to the latter group and through desmoplakin and plakoglobin are the link to the intracellular network of keratin 1 intermediate filaments. Antibodies of patients with pemphigus vulgaris recognize desmoglein-3 (130 kd) and those with pemphigus foliaceus (PF) recognize desmoglein-1 (160 kd). 1,2 Although spontaneous disease develops in most patients (idiopathic pemphigus), in some the disease is precipitated by drugs (induced pemphigus). 3 We describe a patient in whom, during treatment with D-penicillamine for mixed connective tissue disease, PF developed. CASE REPORT A 33-year-old woman had a 6-month history of diffuse hyperpigmentation, arthritis, sicca syndrome, cutaneous sclerosis, and Raynauds phenomenon. Laboratory examination disclosed an antinuclear antibody titer of more than 1:10240 (nucleolar pattern), anti-double-stranded DNA titer of 1:132, and positive anti-SS-A. Antibodies to SS-B, ribonucleoprotein (RNP), Sin, Jo-1, centromere, and Scl-70 were not found. Esophageal manometry showed decreased peristalsis in the distal two thirds. No calcifications

MicroRNA-135b Regulates Leucine Zipper Tumor Suppressor 1 in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin malignancy and it presents a therapeutic challenge in organ transplant recipient patients. Despite the need, there are only a few targeted drug treatment options. Recent studies have revealed a pivotal role played by microRNAs (miRNAs) in multiple cancers, but only a few studies tested their function in cSCC. Here, we analyzed differential expression of 88 cancer related miRNAs in 43 study participants with cSCC; 32 immunocompetent, 11 OTR patients, and 15 non-lesional skin samples by microarray analysis. Of the examined miRNAs, miR-135b was the most upregulated (13.3-fold, 21.5-fold; p=0.0001) in both patient groups. Similarly, the miR-135b expression was also upregulated in three cSCC cell lines when evaluated by quantitative real-time PCR. In functional studies, inhibition of miR-135b by specific anti-miR oligonucleotides resulted in upregulation of its target gene LZTS1 mRNA and protein levels and led to decreased cell motility and invasion of both primary and metastatic cSCC cell lines. In contrast, miR-135b overexpression by synthetic miR-135b mimic induced further down-regulation of LZTS1 mRNA in vitro and increased cancer cell motility and invasiveness. Immunohistochemical evaluation of 67 cSCC tumor tissues demonstrated that miR-135b expression inversely correlated with LZTS1 staining intensity and the tumor grade. These results indicate that miR-135b functions as an oncogene in cSCC and provide new understanding into its pathological role in cSCC progression and invasiveness.