The serotonin transporter protein is expressed in psoriasis, where it may play a role in regulating apoptosis

Abstract

Since the symptoms of psoriasis may be changed by treatment with selective serotonin reuptake inhibitors (SSRIs), the expression of serotonin (5-HT) and its transporter protein (SERT) in the skin of patients with psoriasis were examined employing a biotinylated-streptavidine procedure. In biopsies of such skin staining for 5-HT was limited to platelets; the expression of SERT in the keratinocytes of involved regions was redistributed; the numbers of SERT-positive dendritic or round mononuclear cells in the epidermis of involved psoriatic skin were higher than in normal healthy control skin; and the dermis of the involved skin contained higher numbers of round inflammatory cells immunostained for SERT than either non-involved psoriatic skin or normal skin. Double-immunostaining indicated that the skin cells expressing SERT also expressed CD1a, CD3 or tryptase. In addition, SERT immunostaining was co localized with caspase-3, a key regulator of apoptosis, but not with TUNEL staining. The present findings indicate that SERT might play a role in regulating apoptosis in inflammatory cells associated with psoriasis, in which case this protein might constitute a valuable therapeutic target.

Use of serotonin reuptake inhibitors in patients with psoriasis is associated with a decreased need for systemic psoriasis treatment: a population‐based cohort study

“…We also found that this protein colocalized with caspase-3, an apoptosis-regulating protein [9]. These findings suggest that the serotonergic system may be regulating the process of inflammation observed in psoriasis.…”

“…The source population was all Swedish residents ever diagnosed with plaque psoriasis by dermatologists (ICD codes L40.0, L40.5 and L40. [8][9] and registered in the National Patient Register (inhospital care during 1997-2006 and outpatient care during [2001][2002][2003][2004][2005][2006] [12]. In total, 69 830 patients with plaque psoriasis were identified.…”

Introduction

“…Serotonin was also detected by immunocytochemistry in dermal Merkel cells in rat and pig skin at the epidermal rete ridges and upper hair follicles adjacent to nerve terminals (Nordlind et al, 2008). Cutaneous serotonin content can be affected by inflammatory processes (Lonne-Rahm et al, 2008, Nordlind et al, 2008, Rasul et al, 2011, Thorslund et al, 2009). For example, human skin affected by psoriasis or chronic eczema showed elevated expression of serotonin in the epidermal and adnexal structures (Nordlind et al, 2007; 2008)…”

Time‐dependent modulation of serotonin and its receptors 1A and 2A expression in allergic contact dermatitis

“…14-16 An example of 5-HT mediated cutaneous neurogenic inflammation is its implication in atopic dermatitis 17,18 and psoriasis, [19][20][21] in addition to its significant role in initiating contact dermatitis. 22 5-HT is also implicated in several physiological functions as well as pathological conditions.…”