The Anti-inflammatory Effect of the Tricyclic Antidepressant Clomipramine and Its High Penetration in the Brain Might Be Useful to Prevent the Psychiatric Consequences of SARS-CoV-2 Infection.

At the time of writing (December 2020), coronavirus disease 2019 (COVID-19) has already caused more than one million deaths worldwide, and therefore, it is imperative to find effective treatments. The "cytokine storm" induced by Severe Acute Respiratory Syndrome-Coronavirus type 2 (SARS-CoV-2) is a good target to prevent disease worsening, as indicated by the results obtained with tocilizumab and dexamethasone. SARS-CoV-2 can also invade the brain and cause neuro-inflammation with dramatic neurological manifestations, such as viral encephalitis. This could lead to potentially incapacitating long-term consequences, such as the development of psychiatric disorders, as previously observed with SARS-CoV. Several pathways/mechanisms could explain the link between viral infection and development of psychiatric diseases, especially neuro-inflammation induced by SARS-CoV-2. Therefore, it is important to find molecules with anti-inflammatory properties that penetrate easily into the brain. For instance, some antidepressants have anti-inflammatory action and pass easily through the blood brain barrier. Among them, clomipramine has shown very strong anti-inflammatory properties in vitro, in vivo (animal models) and human studies, especially in the brain. The aim of this review is to discuss the potential application of clomipramine to prevent post-infectious mental complications. Repositioning and testing antidepressants for COVID-19 management could help to reduce peripheral and especially central inflammation and to prevent the acute and particularly the long-term consequences of SARS-CoV-2 infection.

Merkel cell polyomavirus DNA detection in lesional and nonlesional skin from patients with Merkel cell carcinoma or other skin diseases.

Background A novel polyomavirus, the Merkel cell polyomavirus (MCPyV), has recently been identified in Merkel cell carcinoma (MCC). Objectives To investigate the specificity of this association through the detection, quantification and analysis of MCPyV DNA in lesional and nonlesional skin biopsies from patients with MCC or with other cutaneous diseases, as well as in normal skin from clinically healthy individuals. Methods DNA was extracted from lesional and nonlesional skin samples of patients with MCC or with other cutaneous diseases and from normal-appearing skin of clinically healthy subjects. MCPyV DNA was detected by polymerase chain reaction (PCR) and quantified by real-time PCR. Additionally, the T antigen coding region was sequenced in eight samples from seven patients. Results MCPyV DNA was detected in 14 of 18 (78%) patients with MCC, five of 18 (28%) patients with other skin diseases (P = 0.007) and one of six (17%) clinically healthy subjects. In patients with MCC, viral DNA was detected in nine of 11 (82%) tumours and in 10 of 14 (71%) nontumoral skin samples (P = 0.66). MCPyV DNA levels were higher in MCC tumours than in nontumoral skin from patients with MCC, and than in lesional or nonlesional skin from patients with other cutaneous disorders. Signature mutations in the T antigen gene were not identified in the two MCC tumour specimens analysed. Conclusions High prevalence and higher levels of MCPyV DNA in MCC supports a role for MCPyV in tumorigenesis. However, the high prevalence of MCPyV in the nontumoral skin and in subjects without MCC suggests that MCPyV is a ubiquitous virus.

[Development of new skin substitutes based on bioresorbable polymer for treatment of severe skin defects]. / Développement de nouveaux substituts cutanés à base de polymères biorésorbables pour la prise en charge des affections cutanées sévères.

Over the last years, increasing attention has been paid to skin engineering due to its predominant function in body integrity. Thus, many laboratories are attempting to develop a dermal-epidermal complex. The aim of this study was to evaluate the potential of poly(alpha-hydroxyacid)s in the development of biocompatible and bioresorbable dermal scaffold combining human fibroblasts and keratinocytes, in order to obviate the drawbacks of using natural polymers such as collagen, hyaluronic acid and fibrin. We first confirmed the interest of poly(d,l-lactic acid) (PLA(50)) during the reconstitution of epidermis and next, we investigated the potential of poly(d,l-lactic acid)-poly(ethylene glycol)-poly(d,l-lactic acid) (PLA(50)-PEG-PLA(50)) for either skin cytocompatibility or scaffold processing. Data showed that PLA(50)-PEG-PLA(50) is compatible with the culture of human skin cells (fibroblasts and keratinocytes) and the development of a porous scaffold; two requirements compulsory for being considered as an adequate skin substitute. In fine, this material could represent the first generation of new skin dressings, i.e. a new concept taking advantage of both implantable devices and current dressings.

Reverse transcriptase activity in human normal and psoriatic skin samples.

BACKGROUND: About half of the human genome is composed of ancient transposable elements that became integrated in the genome throughout the course of evolution by DNA transposition or by retrotransposition. Most of these elements have degenerated. However, a few of them have conserved their coding capacities and could still have a role in physiological and pathological processes. OBJECTIVES To investigate whether reverse transcriptase (RT) of human endogenous retroelements can be expressed at the protein level and can also be functional, and to associate RT expression and activity to a pathological situation, namely psoriasis. METHODS: Expression of RT proteins was investigated by immunohistochemistry on normal (n = 11), psoriatic (n = 19) and atopic (n = 12) skin sections and by Western blot on normal skin protein extracts. RT activity was measured by a colorimetric method in protein extracts from normal (n = 17) and lesional psoriatic (n = 35) skin. Two assays were performed in each extract: one was optimized for Moloney murine leukaemia virus or mammalian C-type retroviruses, and the other for mouse mammary tumour virus or D-type retroviruses. RESULTS: RT proteins were detected in the uppermost layer of the epidermis and in a few dermal cells of normal skin. The main protein had a molecular weight of 57 kDa. An increased number of RT-positive cells was stained in the psoriatic lesion both within the epidermis and within the dermal compartment. In addition, a massive staining was noted in Munro's abscesses. Finally, RT activities were 2-3 times higher in psoriatic protein extracts than in normal skin protein extracts. CONCLUSIONS: Active endogenous retroelements can produce functional RT proteins. In normal skin, we observed RT expression in all samples tested whereas RT activity was barely detectable. In psoriatic samples, the number of RT-positive cells was increased, as was the RT activity. This latter characteristic allowed us to determine a subset of psoriatic samples with an increased Mg(2+) RT activity. These results suggest that a basal level of endogenous retroelement activity exists in normal skin and that keratinocyte hyperproliferation and/or inflammation observed in psoriasis promote this activity. The role of endogenous retroelements in skin physiology and pathology deserves attention.

A new endogenous retroviral sequence is expressed in skin of patients with psoriasis.

BACKGROUND: The origin of psoriasis, a chronic inflammatory skin disease involving keratinocyte proliferation, immune disturbances and complex inheritance, remains unknown. Human endogenous retroviruses (HERVs) are part of the normal human genome and their participation in the pathogenesis of various human diseases with complex genetic traits has been proposed. A possible role of HERVs in the induction of psoriasis was suggested many years ago. However, to date no study has searched for HERV expression in psoriasis. OBJECTIVES: To determine firstly, which HERV families are expressed in the psoriatic lesion and secondly, whether specific variants can be detected. METHODS: HERV expression was analysed at the mRNA level after degenerated reverse transcription-polymerase chain reaction (RT-PCR) of retroviral pol sequences followed by sequencing. Screening for a specific variant was performed by RT-PCR on lesional and nonlesional psoriatic skin and compared with normal and atopic dermatitis skin. RESULTS: We report the expression of three HERV families in psoriatic lesions, namely HERV-W, K and E. We then partially characterized a new endogenous retroviral variant, which was related to the ERV-9/HERV-W family. This sequence contains at least two open reading frames that could encode for a gag protein and a retroviral protease. The expression of this sequence was detected in 29 of 43 lesional psoriasis skin samples and rarely in normal (two of 21) or atopic dermatitis (three of 14) skin samples. CONCLUSIONS: In psoriatic lesions, HERV sequences of the W, K and E families are expressed and a new variant of the ERV-9/HERV-W family has been characterized. The possible role of HERV-related sequences in the pathogenesis of psoriasis is under investigation.

Differential expression of a human endogenous retrovirus E transmembrane envelope glycoprotein in normal, psoriatic and atopic dermatitis human skin.

BACKGROUND: Psoriasis is a common inflammatory skin disease characterized by uncontrolled proliferation of keratinocytes and recruitment of T lymphocytes into the skin. The possible role of human endogenous retroviruses (HERVs) in the induction of psoriasis has been suggested, based upon the previous observations of retrovirus-like particles in psoriasis from skin lesional plaques, urine and stimulated lymphocytes. OBJECTIVES: To investigate the expression of HERV-E transmembrane envelope glycoprotein (HERV-E env) in normal, psoriatic and atopic human skin, and to examine the influence of ultraviolet (UV) B irradiation on HERV-E env expression in normal human epidermal keratinocytes. METHODS: The analysis was performed on both skin biopsies and organotypic skin cultures using immunofluorescence and Western immunoblotting. UVB irradiation (312 nm) of cultured normal human keratinocytes was performed using a dose of 30 mJ cm(-2). RESULTS: Positive staining was observed in most of the psoriatic and atopic skin samples, whereas only 15% of the normal skin samples were faintly positive. In addition, the pattern of expression of HERV-E env differed markedly in psoriasis vs. atopy. By Western blotting analysis, two main proteins of 54 and 57 kDa were detected in extracts of normal skin, normal keratinocyte cultures and reconstructed epidermis from psoriatic and normal punch biopsies. An increased level of expression of these proteins was noted in extracts from psoriatic vs. normal reconstructed epidermis. The overexpression of the 57-kDa protein in normal human cultured keratinocytes was dramatically reduced by UVB irradiation. CONCLUSIONS: These data suggest for the first time that HERV-E env is expressed in normal and pathological human skin. Further studies are now required to elucidate the role of such viral proteins in the pathogenesis of psoriasis.

Association between INK4a-ARF and p53 mutations in skin carcinomas of xeroderma pigmentosum patients.

BACKGROUND: The INK4a-ARF locus encodes two tumor suppressor proteins, p16(INK4a) and p14(ARF), that act through the Rb-CDK4 and p53 pathways, respectively. Data from murine models and sporadic human skin carcinomas implicate p16(INK4a) and p14(ARF) in the development of skin carcinomas. We examined the frequency of INK4a-ARF, p53, and CDK4 mutations in skin carcinomas from patients with xeroderma pigmentosum (XP), a rare autosomal disease that is associated with a defect in DNA repair and that predisposes patients to skin cancer. METHODS: DNA from skin cancers of 28 unrelated XP patients was screened for mutations in p53, INK4a-ARF, and CDK4 coding exons by single-strand conformation polymorphism analysis and automated sequencing. Data were evaluated with the use of the exact unconditional test derived from Fisher's test. All statistical tests were two-sided. RESULTS: Eight of 28 XP-associated tumors had mutations in the INK4a-ARF locus. Three XP-associated tumors had multiple mutations at this locus. In all, 13 mutations in the INK4a-ARF locus were detected in XP-associated tumors, of which seven (54%) were signature UV radiation-induced mutations, i.e., tandem CC : GG-->TT : AA transitions. p53 mutations, mostly of the type induced by UV radiation, were present in 12 tumors (43%). Statistically significant positive associations were found between the frequency of mutations in p53 and in p16(INK4a) (P =.008) and between the frequency of mutations in p53 and in p14(ARF) (P<.001). No mutations were detected within the CDK4 gene. CONCLUSIONS: We have demonstrated for the first time the occurrence of UV radiation-induced mutations in INK4a-ARF in XP-associated skin carcinomas. The simultaneous inactivation of p53 and INK4a-ARF may be linked to the genetic instability caused by XP and could be advantageous for tumor progression.

A three-dimensional skin culture model for mouse keratinocytes: application to transgenic mouse keratinocytes.

The study of mouse epidermal biology has been hampered by the lack of a good in vitro model for the culture of mouse keratinocytes which allowed the reconstruction of a fully differentiated epidermis. We adapted the Pruniéras' model, also called the Dead de-Epidermized Dermis model (DED), to mouse keratinocytes and showed that a neo-epidermis can be reconstructed exhibiting a complete differentiation program. We also used this model to culture transgenic mouse keratinocytes. We observed that transgene expression occurred in the correct location and that the neo-epidermis mimed previous in vivo observations obtained with integrin skin-targeted transgenic mice. Therefore, this model will be a powerful tool to further investigate normal mouse and transgenic keratinocyte biology.

[Beta-catenin mutations in a common skin cancer: pilomatricoma]. / Des mutations de la caténine beta induisent des tumeurs cutanées: les pilomatricomes.

The normal hair development requires WNT signalling pathways. A constitutive activation of beta-catenin, one of the components of this cascade, induces an abnormal proliferation of hair matrix cells. This activation is observed in a human skin tumours called pilomatricoma. Mutations of the beta-catenin gene are detected in 75% of the tumours analysed.

P16 UV mutations in human skin epithelial tumors.

The p16 gene expresses two alternative transcripts (p16alpha and p16beta) involved in tumor suppression via the retinoblastoma (Rb) or p53 pathways. Disruption of these pathways can occur through inactivation of p16 or p53, or activating mutations of cyclin dependant kinase 4 gene (Cdk4). We searched for p16, Cdk4 and p53 gene mutations in 20 squamous cell carcinomas (SSCs), 1 actinic keratosis (AK), and 28 basal cell carcinomas (BCCs), using PCR-SSCP. A deletion and methylation analysis of p16 was also performed. Six different mutations (12%) were detected in exon 2 of p16 (common to p16alpha and p16beta), in five out of 21 squamous lesions (24%) (one AK and four SCCs) and one out of 28 BCCs (3.5%). These included four (66%) ultraviolet (UV)-type mutations (two tandems CC : GG to TT : AA transitions and two C : G to T : A transitions at dipyrimidic site) and two transversions. P53 mutations were present in 18 samples (37%), mostly of UV type. Of these, only two (one BCC and one AK) harboured simultaneously mutations of p16, but with no consequence on p16beta transcript. Our data demonstrate for the first time the presence of p16 UV induced mutations in non melanoma skin cancer, particularly in the most aggressive SCC type, and support that p16 and p53 are involved in two independent pathways in skin carcinogenesis.

[The gene of Gorlin's syndrome (basocellular nevomatosis) and the revival of the developmental genes in human carcinogenesis]. / Le gène du syndrome de Gorlin (naevomatose basocellulaire) et le renouveau des gènes du développement en carcinogenèse humaine.

Interaction between developmental biology and human pathology has brought new insight on basal cell carcinoma oncogenesis. Alterations of the Patched gene appear to be responsible for the Gorlin syndrome and to be detected in 50% of the sporadic basal cell carcinomas. This relation has recently been extended to all the components of the Hedgehog signalling pathway.

The epidermal stem cell compartment: variation in expression levels of E-cadherin and catenins within the basal layer of human epidermis.

The basal layer of the epidermis contains two types of proliferating keratinocyte: stem cells, with high proliferative potential, and transit amplifying cells, which are destined to undergo terminal differentiation after a few rounds of division. It has been shown previously that two- to three-fold differences in the average staining intensity of fluorescein-conjugated antibodies to beta 1 integrin subunits reflect profound differences in the proliferative potential of keratinocytes, with integrin-bright populations being enriched for stem cells. In the search for additional stem cell markers, we have stained sections of normal human epidermis with antibodies to proteins involved in intercellular adhesion and quantitated the fluorescence of individual cell-cell borders. In the basal layer, patches of brightly labeled cells were detected with antibodies to E-cadherin, beta-catenin, and gamma-catenin, but not with antibodies to P-cadherin, alpha-catenin, or with pan-desmocollin and pan-desmoglein antibodies. In the body sites examined, palm and foreskin, integrin-bright regions were strongly labeled for gamma-catenin and weakly labeled for E-cadherin and beta-catenin. Our data suggest that there are gradients of both cell-cell and cell-extracellular matrix adhesiveness within the epidermal basal layer and that the levels of E-cadherin and of beta- and gamma-catenin may provide markers for the stem cell compartment, stem cells expressing relatively higher levels of gamma-catenin and lower levels of E-cadherin and beta-catenin than other basal keratinocytes.

Correlation between hyperproliferation and suprabasal integrin expression in human epidermis reconstituted in culture.

In normal epidermis integrin expression is largely confined to the basal layer. However, during wound healing and in psoriatic lesions suprabasal expression is observed. Although the potential importance of suprabasal integrin expression in the pathogenesis of psoriasis has been established, the cause of suprabasal expression is unknown. We now describe changes in integrin expression that occur with time when normal human keratinocytes are grown on two types of dermal equivalent, de-epidermized dermis and collagen gels containing fibroblasts. We show that suprabasal integrin expression is correlated with suprabasal expression of the EGF receptor, but not with expression of keratin 10 or keratin 16. By quantitating the proportion of basal keratinocytes expressing the proliferation marker Ki-67 we could show that suprabasal integrin expression is correlated with high proliferative activity within the basal layer. Taken together with our earlier work, these results suggest that suprabasal integrin expression is linked to hyperproliferation and not to abnormal terminal differentiation or to inflammation; they also establish dermal equivalent cultures as useful experimental models with which to manipulate keratinocyte integrin expression.

1,25-Dihydroxyvitamin D3 and its synthetic derivatives MC903 and EB1089 induce a partial tumoral phenotype reversal in a skin-equivalent system.

The antitumoral potency of 1,25-dihydroxyvitamin D3 and its synthetic derivatives MC903, EB1089, and KH1060 was investigated on a tumoral Bowen-like epidermis reconstructed from an immortalized human keratinocyte cell line transfected by expression vectors coding for E6 and E7 of human papillomavirus 16. Treatment of skin equivalents by vitamin D derivatives (10(-9) M or 10(-12) M) was performed during (from day 1 to day 15 of culture) or after tissue reconstruction (from day 15 to day 30). Pharmacologic effects were evaluated by morphologic and immunohistologic analysis and compared with those of controls (vehicle alone) and with treatment of skin equivalents derived from normal keratinocytes. When performed during epidermal reconstruction, treatment of tumoral skin equivalents induced only minor morphologic and immunohistologic changes. Conversely, when performed after epidermal reconstruction, treatment with 1,25-dihydroxyvitamin D3, MC903, and EB1089 clearly improved the phenotype of treated tissues. Morphologic analysis showed reorganization of epidermal layers with the appearance of a distinct basal layer and of stratified orthokeratotic stratum corneum. Immunohistochemical analysis demonstrated that the terminal differentiation markers profilaggrin and cytokeratin 10 were re-expressed in the treated tissues while absent in controls. Overall, the results indicate that 1,25-dihydroxyvitamin D3, MC903, and EB1089 can induce a partial reversion of the tumoral phenotype in this in vitro model.

ras, p53 and HPV status in benign and malignant prostate tumors.

To study the role of ras, p53 genes and HPV virus (16 and 18) in the development of prostate cancer, we analyzed tissue sections from 27 patients affected with carcinomas (stages A to D) and from 24 patients with adenomas. Mutations of H, K and N-ras and p53 (exons 2-9) were studied by SSCP and DNA sequencing. Accumulation of p53 protein was studied by immunohistochemistry on tissue sections. Tumors were also analyzed for the presence of HPV16 and -18 sequences by PCR and DNA hybridization with sequence-specific oligonucleotides. No mutation was found in the three ras genes studied, either in carcinomas or adenomas. By SSCP analysis we identified p53 mutations in only 2 of 19 carcinomas studied, both in exon 7. Immunohistochemical results strongly correlate with the SSCP results: p53 protein was positive in tumors with p53 mutation but not in others; 32% of studied adenomas had detectable HPV16 DNA, while 53% of carcinomas were HPV16+. Among these I presented a p53 mutation. No HPV18 E6 sequence could be detected. Our data show that in prostate tumors from France, mutations of p53 and ras are rare events but that these tumors display detectable HPV16 DNA at a high frequency. The low incidence of p53 mutation, associated to a significant proportion of tumors showing HPV16 DNA, could suggest that in prostate cancer HPV16 infection could participate in p53 inactivation by E6.