Cytokine expression patterns distinguish HIV associated skin diseases

Molecular Biology of KSHV in Relation to HIV/AIDS-Associated Oncogenesis

Discovered in 1994, Kaposi's sarcoma-associated herpesvirus (KSHV) has been associated with four human malignancies including Kaposi's sarcoma, primary effusion lymphoma, a subset of multicentric Castleman's disease, and KSHV inflammatory cytokine syndrome. These malignancies mostly occur in immunocompromised patients including patients with acquired immunodeficiency syndrome and often cause significant mortality because of the lack of effective therapies. Significant progresses have been made to understand the molecular basis of KSHV infection and KSHV-induced oncogenesis in the last two decades. This chapter provides an update on the recent advancements focusing on the molecular events of KSHV primary infection, the mechanisms regulating KSHV life cycle, innate and adaptive immunity, mechanism of KSHV-induced tumorigenesis and inflammation, and metabolic reprogramming in KSHV infection and KSHV-transformed cells.

[Skin symptoms associated with human immunodeficiency virus infection]

The recently observed accelerated increase of human immunodeficiency virus infection in Hungary poses a major public concern for the healthcare system. Given the effective only but not the curative therapy, prevention should be emphasized. Current statistics estimate that about 50% of the infected persons are not aware of their human immunodeficiency virus-positivity. Thus, early diagnosis of the infection by serological screening and timely recognition of the disease-associated symptoms are crucial. The authors' intention is to facilitate early infection detection with this review on human immunodeficiency virus-associated skin symptoms, and highlight the significance of human immunodeficiency virus care in the everyday medical practice.

Antimicrobial peptides human beta-defensins and cathelicidin LL-37 induce the secretion of a pruritogenic cytokine IL-31 by human mast cells

In addition to their microbiocidal properties, human beta-defensins (hBDs) and cathelicidin LL-37 stimulate a number of mammalian cell activities, including migration, proliferation, and cytokine/chemokine production. Because hBDs and LL-37 cause mast cells to release pruritogens such as histamine and PGs, we hypothesized that these peptides would stimulate the secretion of a novel pruritogenic mediator IL-31, predominantly produced by T cells. hBDs and LL-37 enhanced IL-31 gene expression and IL-31 protein production and release in the human mast cell line LAD2, as well as in peripheral blood-derived cultured mast cells, suggesting that mast cells are another source of IL-31. Moreover, the expression of IL-31 was elevated in psoriatic skin mast cells, and hBD-2-4 and LL-37, but not hBD-1, enhanced its expression in vivo in rat skin mast cells. hBDs and LL-37 also induced the release of other pruritogenic mediators, including IL-2, IL-4, IL-6, GM-CSF, nerve growth factor, PGE(2), and leukotriene C(4), and increased mRNA expression of substance P. hBD- and LL-37-mediated IL-31 production/release was markedly reduced by pertussis toxin and wortmannin, inhibitors of G-protein and PI3K, respectively. As evidenced by the inhibitory effects of MAPK-specific inhibitors, hBD-2-4 and LL-37 activated the phosphorylation of MAPKs p38, ERK, and JNK that were required for IL-31 production and release. The ability of hBDs and LL-37 to stimulate the production and release of IL-31 by human mast cells provides a novel mechanism by which skin-derived antimicrobial peptides/proteins may contribute to inflammatory reactions and suggests a central role of these peptides in the pathogenesis of skin disorders.

Inflammatory papillomatous hyperplasia and epidermal necrosis in a transgenic rat for HIV-1

BACKGROUND

Skin lesions commonly affect AIDS patients. The pathogenesis of certain dermatologic disorders primarily associated to HIV-1 is unclear, and better forms of therapy for these conditions need to be discovered. Transgenic animal models represent a novel approach for the study of these disorders and for the quest of more effective forms of treatment.

OBJECTIVE

Characterize this HIV-1 transgenic rat as a model to study skin diseases related to HIV/AIDS.

METHODS

A transgenic rat was developed, using an HIV-1 construct with deleted gag and pol genes. Morphological and genotypical evaluations were followed by cytokine profile characterization of the lesions.

RESULTS

We report the characterization of a colony of HIV-1 transgenic rats that developed skin lesions in a frequency of 22.5%. Cutaneous expression of functional HIV-1 transgenes correlated precisely with the severity of the phenotype. In early stages, rats manifested localized areas of xerosis and dispersed papulosquamous lesions. These hyperplastic manifestations were observed in conjunction with an increased epidermal expression of tat protein and a Th1/Th2 profile of cytokines. As the lesions progressed, they formed inflammatory plaques that subsequently ulcerated. Histologically, these lesions displayed a profound lymphocytic infiltrate, epidermal necrosis, and a marked increase of both Th1 and Th2 derived cytokines. Moreover, the presence of circulating IgG antibodies against HIV-1 gp120 was detected.

CONCLUSION

This animal model as other HIV-1 transgenic mice described in the past, is not able to fully explain the myriad of skin findings that can occur in HIV-infected humans; however, it represents a potential animal model system for the study of immune-mediated inflammatory skin diseases.

Abnormal expression of interleukin-23 in mycosis fungoides/Sézary syndrome lesions

Progression of mycosis fungoides (MF) to Sézary syndrome (SS) is accompanied by a shift from a T(H)1 to a T(H)2 cytokine profile. Interleukin (IL)-23 is a novel cytokine that shares a common p40 subunit with the T(H)1 inducer, IL-12. IL-23 induces a third profile, T(H)IL-17, that is dominant in inflammation and autoimmunity. Although IL-23 induces an eczematous-like skin reaction in mice, and is expressed in T(H)1-mediated skin disorders such as psoriasis, it has not been evaluated in MF/SS. To study the role of IL-23 in MF/SS development, 40 MF/SS lesions of all stages were immunohistochemically analyzed with a novel anti-human IL-23 antibody raised against full-length human IL-23. IL-23 was detected with the catalyzed signal amplification system. The intensity and frequency of IL-23 staining were semi-quantitatively graded in both the dermal infiltrate and the epidermis. Increased expression of IL-23 was observed throughout the epidermal keratinocytes and in dermal lymphocytes compared to normal skin. IL-23 intensity did not differ significantly among the stages of MF/SS; however, in stage IVB patients, we observed lower frequency of IL-23 expression in dermal lymphocytes than in other stage patients [P = 0.13, analysis of variance (ANOVA)]. Interestingly, clusters of atypical lymphocytes, especially the epidermotropic tumor cells, demonstrated weak or absent IL-23 staining in 18 of 40 (45%) lesions. This finding was present in 4 of 5 (80%) of the stage IVB lesions and 7 of 11 (64%) of the lesions from Sézary patients. These findings indicate that abnormal IL-23 expression may play a role in the pathogenesis and progression of MF/SS.

Cutaneous markers of HIV infection

Despite the development of laboratory methods, dermatological symptoms are a basic index of the presence and physical course of HIV infection. HIV infection usually undergoes a long latent period, proceeds to a period of immunodeficiency-related symptoms, and ends in an advanced immunodeficiency state characterized by opportunistic infections and neoplasms. Occasionally, dermatological manifestations can be the first signs of asymptomatic disease, indices of advanced immunodeficiency, or symptoms of opportunistic infections or neoplasms. The variety of symptoms and signs for the skin during the course of HIV infection is a consequence of the progressing immunodeficiency and therefore indicates the underlying disorder. The use of these manifestations is a challenge for clinical praxis.

Similar activation of signal transduction pathways by the herpesvirus-encoded chemokine receptors US28 and ORF74

The virally encoded chemokine receptors US28 from human cytomegalovirus and ORF74 from human herpesvirus 8 are both constitutively active. We show that both receptors constitutively activate the transcription factors nuclear factor of activated T cells (NFAT) and cAMP response element binding protein (CREB) and that both pathways are modulated by their respective endogenous receptor ligands. By addition of specific pathway modulators against the G protein subunit Galphai, phospholipase C, protein kinase C, calcineurin, p38 MAP kinase, and MEK1, we find that the constitutive and ligand-dependent inductions are mediated by multiple yet similar pathways in both receptors. The NFAT and CREB transcription factors and their upstream activators are known inducers of host and virally encoded genes. We propose that the activity of these virally encoded chemokine receptors coordinates host and potentially viral gene expression similarly. As ORF74 is a known inducer of neoplasia, these findings may have important implications for cytomegalovirus-associated pathogenicity.

Tazarotene-induced gene 3 is suppressed in basal cell carcinomas and reversed in vivo by tazarotene application

Basal cell carcinomas are the most common form of skin cancer. Tazarotene is a retinoic acid receptor selective retinoid that upregulates a tumor suppressor, tazarotene-induced gene 3 (TIG-3), in keratinocytes and psoriasis. Expression of TIG-3 in basal cell carcinomas was studied in an opened-label pilot biomarker study of 22 patients with basal cell carcinomas who applied tazarotene 0.1% gel for up to 12 wk prior to excision. Nineteen paired baseline and treated specimens were compared using immunohistochemistry and in situ hybridization. Compared to overlying normal epidermis, TIG-3 protein and mRNA were decreased in 14 and 18 of 19 basal cell carcinomas (74% and 95%), respectively (p < 0.001). Tazarotene treatment was associated with increased TIG-3 protein and mRNA expression in basal cell carcinomas compared to baseline levels (p < or = 0.001 and p = 0.028, respectively). Sixty percent of basal cell carcinomas treated with tazarotene decreased in size by at least 25%. Ten of 19 lesions improved histologically, including three complete responses. There was a correlation between the increased expression of TIG-3 protein and histologic improvement (p = 0.020), suggesting that suppression of TIG-3 may underlie the development of basal cell carcinomas. This association suggests that reversal of TIG-3 expression may help to explain the mechanism of retinoid action in epidermal differentiation and chemoprevention.

HOXB13 homeodomain protein is cytoplasmic throughout fetal skin development

Substantial evidence suggests that HOX homeobox genes regulate aspects of body development, including hair formation. We initially isolated the HOXB13 gene from human fetal skin in experiments designed to identify candidate genes that regulate scarless fetal wound healing. Although the HOX homeodomain proteins have been proposed to function as transcription factors, we have demonstrated previously that substantial fractions of the HOXB6 and HOXB4 proteins are localized to the cytoplasm throughout epidermal development. The purpose of the current study was to identify HOXB13 protein expression patterns in developing skin to elucidate potential mechanisms by which this protein might regulate aspects of tissue development and healing. HOXB13 protein expression was detected throughout the developing epidermis, with weaker signal observed in the early developing dermis. Epidermal HOXB13 signal was detected over the entire body surface, but surprisingly, essentially all of the signal was cytoplasmic in developing skin. Low-level HOXB13 protein expression was detected in adult skin and within the telogen hair follicle, and a portion of the residual signal in adult epidermis was nuclear. Expression in hyperproliferative skin conditions remained cytoplasmic with the exception of epidermis associated with Kaposi's sarcoma, which showed strong HOXB13 expression that was partially localized to the nucleus.

Polymethylmethacrylate efficacy in reduction of renal itching in hemodialysis patients: crossover study and role of tumor necrosis factor-alpha

Pruritus is one of the major unsolved problems for patients receiving regular hemodialysis. In this study, we conducted a 6 month prospective and crossover trial to investigate the effect of polymethylmethacrylate (PMMA) membrane for renal itching. We also examined the role of the tumor necrosis factor (TNF)-alpha system for pruritus in hemodialysis patients. We assessed the degree of skin itching and measured circulating levels of TNF-alpha and soluble TNF receptors (sTNFR-I, sTNFR-II) in 19 patients using hemodialysis, complicated by prolonged severe pruritus for 6 months. Serum sTNFR-I and II levels were significantly elevated in hemodialysis patients compared to normal subjects. Serum sTNFR-II levels were significantly and negatively correlated with serum albumin (r = -0.602, p = 0.007). A significant positive relationship was also found between sTNFR-I and erythropoietin dosage (r = 0.554, p = 0.016). However, no association was found between the degree of pruritus and circulating sTNFR-I and II values. Skin itching scale was significantly decreased from 2.7 +/- 0.2 to 2.1 +/- 0.3 following the use of PMMA membrane for 3 months (p < 0.05). In contrast, there was no change in itching scales during 3 months of conventional therapy (2.2 +/- 0.3 versus 2.2 +/- 0.3, p = NS). PMMA itself did not affect serum TNF-alpha and sTNFR values as well as conventional dialyzer membranes. These findings suggested that the PMMA dialyzer can improve renal itching not mediated through the modification of the TNF-alpha system.