Allele-specific CRISPR-Cas9 editing of dominant epidermolysis bullosa simplex in human epidermal stem cells

Epidermolysis bullosa simplex (EBS) is a rare skin disease inherited mostly in an autosomal dominant manner. Patients display a skin fragility that leads to blisters and erosions caused by minor mechanical trauma. EBS phenotypic and genotypic variants are caused by genetic defects in intracellular proteins whose function is to provide the attachment of basal keratinocytes to the basement membrane zone and most EBS cases display mutations in keratin 5 (KRT5) and keratin 14 (KRT14) genes. Besides palliative treatments, there is still no long-lasting effective cure to correct the mutant gene and abolish the dominant negative effect of the pathogenic protein over its wild-type counterpart. Here, we propose a molecular strategy for EBS01 patient's keratinocytes carrying a monoallelic c.475/495del21 mutation in KRT14 exon 1. Through the CRISPR-Cas9 system, we perform a specific cleavage only on the mutant allele and restore a normal cellular phenotype and a correct intermediate filament network, without affecting the epidermal stem cell, referred to as holoclones, which play a crucial role in epidermal regeneration.

Acute maculopapular eruption in Covid-19 patient: A case report

We report the case of a positive COVID-19 patient who presented to our hospital for a maculopapular skin rash which appeared 7 days after the onset of COVID-19 symptoms. He was 34 years old and nothing relevant was recorded at his previous anamnesis. The patient was hospitalized for 3 days and received systemic therapy with steroid, antihistamines, tocilizumab, and hydroxicloroquine. On the third day of the hospitalization the cutaneous rash had almost completely disappeared.

Mesenchymal stem cells for the treatment of psoriasis: a comprehensive review

Mesenchymal stem cells (MSCs) have recently been shown to have not only regenerative capabilities but also immunomodulating properties. For this reason, they are currently under investigation in clinical trials for the treatment of several autoimmune systemic disorders. Psoriasis is a systemic immune-mediated disease for which MSCs could have therapeutic potential. We analysed the existing literature with regard to MSC-based strategies for the treatment of psoriasis, using the MEDLINE, Embase, Scopus and Cochrane Library electronic databases from inception to the date of study. A number of studies confirm the involvement of MSCs in psoriasis pathogenesis and therefore designate MSCs as an important potential therapeutic tool in this setting. Preclinical data are mostly based on imiquimod-induced murine models of psoriasis, and confirm the anti-inflammatory and immunomodulatory action of MSCs in the setting of psoriasis. Six patients affected by psoriasis were described in four clinical studies. Despite significant differences in terms of therapeutic protocols and clinical outcomes, the MSC-based regimens were efficacious in 100% of the cases. Despite more data still being needed, MSCs could be a promising therapy for psoriasis.

Which are the main fluorophores in skin and oral mucosa? A review with emphasis on clinical applications of tissue autofluorescence

OBJECTIVES

The present review provides information about which molecules appear to be the main fluorophores in skin and oral mucosa, together with their clinical applications.

DESIGN

The MEDLINE database was searched, using "oral mucosa AND fluorophores", "skin AND fluorophores", "epidermal AND fluorophores", "dermal AND fluorophores" and "cutaneous AND fluorophores" as entry terms. We searched the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The level of evidence in the studies was assessed using the Classification of the Oxford Centre for Evidence-based Medicine (CEBM) Levels for Diagnosis.

RESULTS

Five papers and 17 were primarily focused on description of fluorophores in oral mucosa and skin Evidence exists that fluorophores of oral mucosa and skin are mainly proteins such as collagen, elastin, keratin and tryptophan. Other possible fluorophores identified are: porphyrins, advanced glycation end products, flavins, lipopigment, nicotinamide adenine dinucleotide, flavin adenine dinucleotide, pheomelanin, eumelanin and components of lipofuscin. Clinical applications of oral mucosal autofluorescence (AF) are related to management of malignant and potentially malignant lesions. In the skin, AF has been used for acne assessment, diagnosis of sweat-gland pathologies, glycemic control and management of malignant lesions and as a marker for skin aging.

CONCLUSION

Fluorophores stimulated through AF devices are implied in different physiologic and pathologic processes. AF seems to be useful for several clinical applications, especially in skin department. Because most of the studies show a low level of evidence, further studies are necessary in such a promising and fascinating field.

Dermoscopy of small melanomas: just miniaturized dermoscopy?

BACKGROUND

Small malignant melanomas (MMs) are usually MMs in an initial growth phase, deserving attention by the clinician aiming at an early diagnosis.

OBJECTIVES

To identify clues for early diagnosis of small MMs, by comparing the dermoscopic features of MMs < 4 mm (micromelanomas) with those of larger MMs.

METHODS

Our database consists of dermoscopic images of 482 MMs, which have been retrieved and measured digitally. The ABCD (asymmetry, border, colour, dimension) and 7-point criteria were evaluated for the whole database by three expert dermoscopists, whereas the main dermoscopic pattern was assessed only for micromelanomas. The dermoscopic aspects were correlated to clinical and histological features.

RESULTS

Most 7-point and ABCD scores, and criteria referring to micromelanomas, differed from those of the MM database as a whole. Lesion asymmetry, number of colours, blue-whitish veil, atypical vessels, irregular globules/dots and regression increased according to MM diameter. An inverse trend was observed for atypical network and irregular pigmentation, which were more frequently observed in micromelanomas than in larger ones. Among the 22 micromelanomas, 12 lesions were in situ, whereas the other 10 were 0·2-2 mm thick. The clinical and dermoscopic characteristics of the two groups were similar.

CONCLUSIONS

Micromelanomas are not a rarity. However, the clinician should be aware of the fact that the majority of them lack most of the dermoscopic features presented by larger lesions.

New thymidylate synthase inhibitors induce apoptosis in melanoma cell lines

Malignant melanoma is particularly resistant to conventional chemotherapy and radiotherapy. For this reason in the past years a huge variety of new compounds has been developed with potential chemotherapeutic activity which needs to be tested in vitro and in vivo. We investigated the in vitro action of three new experimental antifolate substances (MR7, MR21 and MR36) with a critical target for thymidylate synthase (TS), an essential enzyme for DNA synthesis. The response of two melanoma cell lines (SK-MEL-2 derived from malignant melanoma metastasis and SK-MEL-28 derived from primary malignant melanoma) was examined after treatment with these substances. The antifolate agents induced apoptosis in SK-MEL-2 and SK-MEL-28 cells as confirmed by the TUNEL technique and Comet Assay. Western-blot analysis showed a down-regulation of Bcl-2 protein level and PARP cleavage, otherwise p53 and Bax expressions were not modulated. Moreover, these antifolate-induced apoptosis was accompanied by both pro-caspase-9 and -8 activations. These results were supported by the use of the pan-caspases inhibitor Z-VAD-FMK that almost completely decreased the amount of apoptosis in both the melanoma cell lines treated with antifolate. In conclusion our results show that TS inhibitors are able to induce apoptosis through a caspase-mediated pathway, but without the involvement of the p53/Bax signalling.

Transcriptional profiles in melanocytes from clinically unaffected skin distinguish the neoplastic growth pattern in patients with melanoma

BACKGROUND

It is generally accepted that sunlight may contribute to the development of melanoma.

OBJECTIVES

To analyse gene expression of melanocytes obtained from clinically unaffected skin of patients with melanoma and healthy controls before and after exposure to ultraviolet B radiation.

METHODS

Using GeneChip array technology, the gene expression of melanocytes obtained from the two donor groups was profiled, in order to identify transcriptional differences affecting susceptibility to melanoma.

RESULTS

The data collected did not show any difference between the expression profiles of melanocytes purified from normal donors and from patients with melanoma that was able to give a statistically significant class separation. However, by means of unsupervised clustering our data could be divided into two main classes. The first class included the transcriptome profiles of melanocytes obtained from skin samples of patients with a vertical growth phase (VGP) melanoma, while the second class included the transcriptome profiles of melanocytes obtained from skin samples of patients with a radial growth phase (RGP) melanoma.

CONCLUSIONS

These data suggest that melanocytes in patients with VGP and RGP melanomas show significant differences in gene expression profiles, which allow us to classify patients with melanoma also from clinically unaffected skin.

Decrease in toxic potential of mixed tensides maintained below the critical micelle concentration: an in vitro study

Sodium lauryl sulphate (SLS) is an anionic tenside widely utilized in commercial topical preparations that may cause skin irritation. It has been shown that the barrier damage caused by SLS in vivo is lower when SLS is used in combination with other tensides which are able to reduce the critical micelle concentration (CMC). The aim of our study was to evaluate if the cytotoxic effect of SLS is reduced by the association with different tensides also at concentrations well below the CMC. Normal human keratinocytes from plastic surgery were grown in serum-free medium. At subconfluency, the cells were treated with SLS at a dose of 0.0025% in combination with cocamidopropyl betaine, Tween 20 and Tween 80 at the minimum toxic dose. Following tenside treatment, the culture medium was changed, and after 24 h the cells were collected for (3)H-thymidine incorporation, the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay and neutral red (NR) uptake. The cytotoxic effect on normal human keratinocytes, as evaluated by (3)H-thymidine incorporation, MTT assay and NR uptake, was significantly decreased by the combination with all the tested tensides. The correlation between cytotoxicity and physical properties was also studied by a conductimetric assay to investigate the mechanism involved in this toxicity reduction.

Ultraviolet B radiation induces activation of neutral and acidic sphingomyelinases and ceramide generation in cultured normal human keratinocytes

The sphingomyelin pathway is an ubiquitous, evolutionary conserved signaling system which transduces an extracellular signal into the cell. During the past few years increasing evidence has shown that the sphingolipid ceramide may play a role as a second messenger in intracellular signal transduction. The ceramide generation via sphingomyelinase (SMase) is followed by three major cellular responses: cell growth arrest, induction of cell differentiation and/or induction of programmed cell death or apoptosis. The aim of this study is to investigate whether activation of SMases and generation of ceramide can be induced by UVB radiation in normal human keratinocytes. The present data show that exposure to UVB radiation results in rapid generation of ceramide. The ceramide accumulation starts 15 min after UV exposure and progressively increases up to 24 h. In vitro measurement of SMase activity following exposure to UVB evidences an activation of both neutral and acidic SMases. Moreover, UVB induces apoptosis in normal human keratinocytes as shown by TUNEL technique and FACS analysis. These data indicate that UVB induced ceramide generation and activation of both neutral and acidic SMases, suggesting that sphingolipids metabolism may be involved in the UVB signaling pathway.

Thickness and echogenicity of the skin in children as assessed by 20-MHz ultrasound

BACKGROUND

Skin anatomy and physiology undergo modifications throughout the whole lifespan. In children the skin appears with structural characteristics, as evaluated by histology, which differ from those of adults, especially in the first years of life.

OBJECTIVE

The aim of our study was to evaluate skin thickness and echogenicity at different sites in children by 20-MHz ultrasound.

METHODS

Eight skin sites of 42 children and 30 young adults were studied with a 20-MHz B scanner. Skin thickness and mean echogenicity were evaluated. The echographic images were processed and segmented by a dedicated program: the 0-30 amplitude interval, which marks the hypoechogenic parts of the tissue, and the 201-255 range, highlighting the hyperreflecting areas, have been selected.

RESULTS AND CONCLUSION

Whereas skin thickness shows a gradual increase from birth to adulthood, maturation of the skin leads to variations in the intensity of its echogenicity, depending on the different skin areas. Whereas on the face and the trunk it appears lower in adults with respect to children, a gradual increase can be observed on the limbs with growing age. The distribution of skin reflectivity also greatly varies in different phases of life.

Ceramide 2 (N-acetyl sphingosine) is associated with reduction in Bcl-2 protein levels by Western blotting and with apoptosis in cultured human keratinocytes

BACKGROUND

Ceramides produced by sphingomyelin hydrolysis activate a cycle that is followed by three different major cellular responses: downregulation of cell proliferation, induction of cell differentiation and apoptosis. In the skin, the generation of intracellular ceramide may also provide a link between an extracellular signal and the induction of the apoptosis programme for the elimination of damaged cells.

OBJECTIVES

We investigated the effect of ceramides capable of entering cells on cultured keratinocytes.

METHODS

Human keratinocytes from neonatal skin were cultured in serum-free medium with or without increasing concentrations of ceramide 2 (CER-2; N-acetyl sphingosine) (5, 10, 20 and 40 micromol L-1). Proliferative effects were studied either by cell counts or by 3H-thymidine incorporation and flow cytometric analysis. Apoptosis was studied by TUNEL staining and Western blot analysis of Bcl-2 protein.

RESULTS

Cell counts and DNA synthesis were reduced in a dose-dependent manner following CER-2 treatment. TUNEL staining showed CER-2-induced apoptosis at 48, 72 and 96 h. Western blot analysis showed that CER-2 induces downregulation of Bcl-2 at 24-96 h.

CONCLUSIONS

These results demonstrate that CER-2 inhibits cell proliferation and induces apoptosis, possibly via a Bcl-2-dependent mechanism.

Autocrine nerve growth factor protects human keratinocytes from apoptosis through its high affinity receptor (TRK): a role for BCL-2

Normal human keratinocytes synthesize and release nerve growth factor (NGF) and express both the low- and the high-affinity NGF receptor. Because NGF has been shown to rescue certain cell types from programmed cell death, we investigated the role of endogenous NGF in preventing keratinocyte apoptosis. We report here that apoptosis is induced in normal human keratinocytes in culture by blocking endogenous NGF signaling with either anti-NGF neutralizing antibody or K252, a specific inhibitor of the tyrosine kinase high-affinity NGF receptor. Apoptosis was assessed by DNA laddering, electron microscopy, and in situ nick end labeling technique. In anti-NGF-treated keratinocytes, the apoptotic process starts at 96 h, and is maximal at 120 h. After K252 treatment, apoptosis starts at 48 h and peaks at 120 h. Because the product of the bcl-2 proto-oncogene protects many cell types from apoptosis, we measured the levels of this protein in apoptotic keratinocytes. We found that both K252 and anti-NGF antibody strikingly downregulate bcl-2 expression, starting at 72 h. Furthermore, HaCat keratinocytes stably transfected with a plasmid containing bcl-2 cDNA fail to undergo apoptosis when treated with K252. These findings show that autocrine NGF acts as a survival factor for human keratinocytes in vitro through its high-affinity NGF receptor, possibly by maintaining constant levels of Bcl-2.

Enhancement of DNA repair in human skin cells by thymidine dinucleotides: evidence for a p53-mediated mammalian SOS response

Thymidine dinucleotide (pTpT) stimulates melanogenesis in mammalian pigment cells and intact skin, mimicking the effects of UV irradiation and UV-mimetic DNA damage. Here it is shown that, in addition to tanning, pTpT induces a second photoprotective response, enhanced repair of UV-induced DNA damage. This enhanced repair results in a 2-fold increase in expression of a UV-damaged chloramphenicol acetyltransferase expression vector transfected into pTpT-treated skin fibroblasts and keratinocytes, compared with diluent-treated cells. Direct measurement of thymine dimers and (6-4) photoproducts by immunoassay demonstrates faster repair of both of these UV-induced photoproducts in pTpT-treated fibroblasts. This enhanced repair capacity also improves cell survival and colony-forming ability after irradiation. These effects of pTpT are accomplished, at least in part, by the up-regulation of a set of genes involved in DNA repair (ERCC3 and GADD45) and cell cycle inhibition (SDI1). At least two of these genes (GADD45 and SDI1) are known to be transcriptionally regulated by the p53 tumor suppressor protein. Here we show that pTpT activates p53, leading to nuclear accumulation of this protein, and also increases the specific binding of this transcription factor to its DNA consensus sequence.

Nerve growth factor receptor and neurochemical markers in human oral mucosa: an immunohistochemical study

BACKGROUND

The innervation of the oral mucosa has so far been studied mainly by histochemical and ultrastructural techniques. Only few studies have investigated the presence of neural proteins and neurotransmitters in human gingival mucosa.

OBJECTIVE

The purpose of the present study was to evaluate the presence and distribution of neural structural and transmitter proteins in different areas of normal human oral mucosa.

METHOD

Indirect immunofluorescence was employed on specimens taken from different mucosal regions (gingiva, lips, gums, palate). Both structural (low-affinity nerve growth factor receptor, NGFr; protein gene product 9.5, PGP 9.5) and neuropeptide markers (substance P; calcitonin gene-related peptide; vasoactive intestinal peptide, neuropeptide Y) were used.

RESULTS

NGFr and PGP 9.5 intensely labelled both nerve fibres and selected epithelial cells, while neuropeptide immunoreactivity was scarcely expressed and exclusively localized in nerve fibres.

CONCLUSIONS

Similarly in the distribution pattern and neurochemistry between oral and cutaneous innervation is apparent. Expression of NGFr could be relevant to the trophism of both the oral innervation and epithelium.

Argentine hemorrhagic fever: early diagnosis by immunofluorescence

A procedure that allows to ascertain a diagnosis of Argentine Hemorrhagic Fever (AHF) as early as 24-48 hours after onset of symptoms is described. An immunofluorescent (IF) test on round cells of urinary sediment was employed. The procedure was assayed on 31 patients with febrile syndrome during epidemic peaks of 1975-1976. It was positive in 19 and negative in 12 cases. The 19 positive cases were confirmed AHF by clinical follow up and serology. From 12 negative cases, 8 belonged to other etiologies and 2 were confirmed AHF. The usefulness of the procedure for early diagnosis is emphasized.

Immunogenicity of A/USSR (H1N1) subunit vaccine in unprimed young adults

A clinical and serological study was performed on 267 of 636 volunteers vaccinated against Argentine hemorrhagic fever with the XJCl3 attenuated strain of Junin virus seven to nine years earlier, in order to determine their long-term evolution. This study included a clinical examination, a chest roentgenogram, an electrocardiogram, and the following laboratory determinations: white and red cell count, number of platelets, hematocrit, hemoglobin, sedimentation rate (Katz index), urea, nitrogen, glucose concentration, cholesterol, GOT, GPT, gamma GT, alkaline phosphatase, cholinesterase, and total bilirubin. Neutralization reactions were performed to determine presistence of antibody levels. All clinical and laboratory findings were within normal limits, excluding a long-term pathology attributable to the virus. Of 165 tested sera, 153 (90.3%) had detectable levels of neutralizing antibodies, and the rest had no antibodies after this time. Although these people live in the endemic area, it is considered that only the 9% that had increased antibody levels had suffered a reinfection during the seven- to nine-year period, which acted as a booster. This figure aproximately coresponds to the subclinical infection value found in the region. In the rest, the persistence of antibodies is attributed to the immunization achieved with the vaccine employed.