Therapeutic potential of stem cells and acitretin on inflammatory signaling pathway-associated genes regulated by miRNAs 146a and 155 in AD-like rats.

Alzheimer's disease (AD) is one of the most common causes of dementia. Several drugs are used to improve the symptoms, but do not stop AD progression. There are more promising treatments that may have a significant role in AD diagnosis and treatment such as miRNAs and stem cells. The present study aims to develop a new approach for AD treatment by mesenchymal stem cells (MSCs) and/or acitretin with special reference to inflammatory signaling pathway as NF-kB and its regulator miRNAs in AD-like rat model. Fourty-five male albino rats were allotted for the present study. The experimental periods were divided into induction, withdrawal, and therapeutic phases. Expression levels of miR-146a, miR-155, necrotic, growth and inflammatory genes were assessed using RT-qPCR. Histopathological examination of brain tissues was performed in different rat groups. The normal physiological, molecular, and histopathological levels were restored after treatment with MSCs and/or acitretin. The present study demonstrates that the miR-146a and miR-155 might be used as promising biomarkers for AD. MSCs and/or acitretin proved their therapeutic potential in restoring the expression levels of targeted miRNAs and their related genes concerning NF-kB signaling pathway.

miRNAs and Stem Cells as Promising Diagnostic and Therapeutic Targets for Alzheimer's Disease.

Alzheimer's disease (AD) is a cumulative progressive neurodegenerative disease characterized mainly by impairment in cognitive functions accompanied by memory loss, disturbance in behavior and personality, and difficulties in learning. Although the main causes of AD pathogenesis are not fully understood yet, amyloid-ß peptides and tau proteins are supposed to be responsible for AD onset and pathogenesis. Various demographic, genetic, and environmental risk factors are involved in AD onset and pathogenesis such as age, gender, several genes, lipids, malnutrition, and poor diet. Significant changes were observed in microRNA (miRNA) levels between normal and AD cases giving hope for a diagnostic procedure for AD through a simple blood test. As yet, only two classes of AD therapeutic drugs are approved by FDA. They are classified as acetylcholinesterase inhibitors and N-methyl-D-aspartate antagonists (NMDA). Unfortunately, they can only treat the symptoms but cannot cure AD or stop its progression. New therapeutic approaches were developed for AD treatment including acitretin due to its ability to cross blood-brain barrier in the brain of rats and mice and induce the expression of ADAM 10 gene, the α-secretase of human amyloid-ß protein precursor, stimulating the non-amyloidogenic pathway for amyloid-ß protein precursor processing resulting in amyloid-ß reduction. Also stem cells may have a crucial role in AD treatment as they can improve cognitive functions and memory in AD rats through regeneration of damaged neurons. This review spotlights on promising diagnostic techniques such as miRNAs and therapeutic approaches such as acitretin and/or stem cells keeping in consideration AD pathogenesis, stages, symptoms, and risk factors.

Eficacia y seguridad de guselkumab y secukinumab en pacientes adultos con psoriasis vulgar severa, no respondedores a terapia tópica y sistémica convencional y no tributario a terapia biológica antagonista al factor de necrosis tumoral por antecedente de neoplasia maligna / Efficacy and safety of guselkumab and secukinumab in adult patients with severe psoriasis vulgaris, non-responsive to conventional topical and systemic therapy and not amenable to biological therapy antagonistic to tumor necrosis factor due to a history of malignancy

ANTECEDENTES: En el marco de la metodología ad hoc para evaluar solicitudes de tecnologías sanitarias, aprobada mediante Resolución de Instituto de Evaluación de Tecnologías en Salud e Investigación N° 111-IETSI-ESSALUD-2021 y ampliada mediante Resolución de Instituto de Evaluación de Tecnologías en Salud e Investigación N° 97-IETSI-ESSALUD2022, se ha elaborado el presente dictamen, el cual expone la evaluación de la eficacia y seguridad de guselkumab y secukinumab en pacientes adultos con psoriasis vulgar severa, no respondedores a terapia tópica y sistémica convencional y no tributario a terapia biológica antagonista al factor de necrosis tumoral disponible en EsSalud por antecedente de neoplasia maligna, en comparación de la mejor terapia de soporte. Así, la médica Evelyn Giuliana Castro Vargas, especialista en dermatología, a través del Comité Farmacoterapéutico del Hospital Nacional Alberto Sabogal Sologuren y siguiendo la Directiva N° 003-IETSI-ESSALUD-2016, envía al Instituto de Evaluación de Tecnologías en Salud e Investigación - IETSI la solicitud de autorización de uso del producto farmacéutico guselkumab no incluido en el Petitorio Farmacológico de EsSalud. ASPECTOS GENERALES La psoriasis es una enfermedad dermatológica inflamatoria crónica no transmisible que afecta aproximadamente del 1 % al 3 % de la población mundial (Augustin et al., 2010) con una prevalencia de alrededor del 2.5 % en el Perú (Rodríguez-Zúñiga, 2016). Esta enfermedad es considerada como un problema de salud pública y de elevada carga para la sociedad (Parisi et al., 2013), lo que se explica por su alto riesgo de morbilidad y porque deteriora la calidad de vida y la salud mental de las personas que lo padecen (Boehnoke & Schón, 2015). El fenotipo de psoriasis más común es la psoriasis vulgar, que se caracteriza por la presencia de placas eritematosas, gruesas y escamosas que se presentan mayormente en cuero cabelludo, glúteos, tronco y extremidades (codos y rodillas). La psoriasis suele clasificarse en leve, moderada y severa, según la clinimetría de las mediciones del Psoriasis Area and Severity Index (PASI), la Body surface area (BSA) y la calidad de vida medida a partir del Dermatology Life Quality Index (DLQI) (Finlay, 2015; Robinson et al., 2012). Es decir, la enfermedad severa se define por tener más de 10 puntos en el PASI, más del 10 % de la superficie corporal (BSA) afectada por la enfermedad, o más de 10 puntos en el DLQI (Strober et al., 2019). Los tratamientos para los pacientes con psoriasis vulgar severa tienen como objetivo lograr una reducción de por lo menos el 75 % o 90 % de la severidad de enfermedad inicial medida por la escala PASI (i.e. PASI75 o PASI90, respectivamente) luego de al menos tres meses de tratamiento efectivo (Belinchón Romero et al., 2021). Asimismo, se considera que, si después de 16 a 24 semanas de la aplicación de un esquema terapéutico efectivo no se ha logrado por lo menos alcanzar el PASI75 con DLQI < 5 o un PASI90, se considera que el paciente no ha respondido al tratamiento (i.e. falla terapéutica) (Aschoff et al., 2021). Así, entre los tratamientos disponibles para la psoriasis tenemos la terapia tópica que se utiliza en los casos de psoriasis leve a moderada', y la terapia sistémica, en casos de psoriasis de moderada a severa2. Dentro de la terapia sistémica, tenemos a los agentes sistémicos convencionales (metotrexato, ciclosporina o acitretina) y la terapia biológica. Ésta última se utiliza generalmente en los casos de falla al tratamiento con agentes sistémicos convencionales (Gisondi et al., 2017). Las terapias biológicas se clasifican según el mecanismo de acción, es decir, según la inhibición dirigida a citoquinas específicas del sistema inmune, tales como el factor de necrosis tumoral alfa (TNF), la interleucina (IL) 17 (IL17) y la IL23 (Fellner, 2016). METODOLOGIA: Se realizó una búsqueda bibliográfica exhaustiva con el objetivo de identificar la mejor evidencia sobre la eficacia y seguridad de guselkumab y secukinumab en pacientes adultos con psoriasis vulgar severa no respondedores a terapia tópica y sistémica convencional y no tributario a terapia biológica anti TNF disponibles en EsSalud por antecedente de neoplasia maligna. La búsqueda se realizó en las bases de datos bibliográficas de PubMed, The Cochrane Library, Web of Science y LILACS (Literatura Latinoamericana y del Caribe en Ciencias 'de la Salud). Asimismo, se realizó una búsqueda dentro de la información generada en las páginas web de grupos o instituciones que realizan revisiones sistemáticas (RS), evaluación de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC), tales como: el National Institute for Health and Care Excellence (NICE), la Agency for Healthcare Research and Quality's (AHRQ), la Scottish Intercollegiate Guidelines Network (SIGN), la New Zealand Guidelines Group (NZGG), la National Health and Medical Research Council (NHMRC), el Instituto de Evaluación de Tecnologías en Salud e Investigación (IETSI), el Centro Nacional de Excelencia Tecnológica en Salud (CENETEC), la Canadian Agency for Drugs and Technologies in Health (CADTH), el Scottish Medicines Consortium (SMC), la Haute Authorité de Santé (HAS), el Institute for Quality and Efficiency in Health Care (IQWiG), la Comissáo Nacional de lncorporagáo de Tecnologías no Sistema Único de Saúde (CONITEC), el Institute for Clinical and Economic Review (ICER) y en la Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas (BRISA). Además, se realizó una búsqueda de las guías en las principales instituciones o sociedades especializadas en dermatología y en psoriasis, tales como la American Academy of Dermatology (AAD), la British Association of Dermatologists (BAD), la European Academy of Dermatology and Venereology (EADV), y la International Psoriasis Council (IPC). Adicionalmente, se llevó a cabo una búsqueda manual en el motor de búsqueda Google utilizando los términos: "Psoriasis guidelines"; revisando documentos de interés en las diez primeras páginas. Finalmente, se realizó una búsqueda adicional en la página web de registro de ensayos clínicos (EC) www.clinicaltrials.gov, para identificar EC en curso o aún no publicados. RESULTADOS: Luego de la búsqueda bibliográfica hasta diciembre de 2022, se identificaron: una GPC de la BAD publicada en el 2020 (Smith et al., 2020); y una RS con MA en red (Sbidian et al., 2022) publicada en el 2022 que fue seleccionada como evidencia indirecta para responder a la pregunta PICO del presente dictamen. CONCLUSIÓN: Por lo expuesto, el Instituto de Evaluación de Tecnologías en Salud e Investigación aprueba el uso de guselkumab en pacientes adultos con psoriasis vulgar severa, no respondedores a terapia tópica y sistémica convencional y no tributario a terapia biológica anti TNF antecedente de neoplasia maligna, como producto farmacéutico no incluido en el Petitorio Farmacológico de EsSalud, según lo establecido en el Anexo N° 1. La vigencia del presente informe preliminar es de un año a partir de la fecha de publicación. Así, la continuación de dicha aprobación estará sujeta a la evaluación de los resultados obtenidos y de mayor evidencia que pueda surgir en el tempo.

In Vitro Effects of Acitretin on Human Neuronal SH-SY5Y Cells.

Acitretin is an oral drug approved by the Food and Drug Administration that is commonly used to treat psoriasis. In recent years, acitretin has been identified as a candidate drug for the treatment of Alzheimer's disease, but its role in neuronal development is still unclear. In this study, the human neuroblastoma cell line SH-SY5Y was used as a model to study neuronal differentiation. We found that acitretin effectively promoted the differentiation of SH-SY5Y cells into neuronal cells and upregulated the expression of the neuronal marker ß-III tubulin and the mature neuronal marker NFH. Differentially expressed genes were identified by RNA sequencing and analyzed by bioinformatics approaches. The results showed that genes associated with neuron development-related pathways, such as SSPO and KCNT1, had significant changes in expression. Analysis showed that PRKCA and CAMK2B may play important roles in the process by which acitretin promotes neurodevelopment. Through whole-cell patch clamping and a microelectrode array assay, we found that acitretin-treated neurons generated electrical spikes similar to those generated by mature neurons. This study provided evidence to support an accessible and safe model of neuron-like cells and verified that acitretin can promote the differentiation of neurons and has the potential to treat brain tumors and neurodevelopmental and neurodegenerative diseases.

The Influence of Acitretin on Brain Lipidomics in Adolescent Mice-Implications for Pediatric and Adolescent Dermatological Therapy.

Administration of systemic retinoids such as acitretin has not been approved yet for pediatric patients. An adverse event of retinoid-therapy that occurs with lower prevalence in children than in adults is hyperlipidemia. This might be based on the lack of comorbidities in young patients, but must not be neglected. Especially for the development of the human brain up to young adulthood, dysbalance of lipids might be deleterious. Here, we provide for the first time an in-depth analysis of the influence of subchronic acitretin-administration on lipid composition of brain parenchyma of young wild type mice. For comparison and to evaluate the systemic effect of the treatment, liver lipids were analogously investigated. As expected, triglycerides increased in liver as well as in brain and a non-significant increase in cholesterol was observed. However, specifically brain showed an increase in lyso-phosphatidylcholine and carnitine as well as in sphingomyelin. Group analysis of lipid classes revealed no statistical effects, while single species were tissue-dependently changed: effects in brain were in general more subtly as compared to those in liver regarding the mere number of changed lipid species. Thus, while the overall impact of acitretin seems comparably small regarding brain, the change in individual species and their role in brain development and maturation has to be considered.

Acitretin enhances the cytotoxic effect of 5-aminolevulinic acid photodynamic therapy on squamous cell carcinoma cells.

The efficacy of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) on invasive cutaneous squamous cell carcinoma (cSCC) remains to be improved due to the limited penetration of this treatment. Previous study showed that acitretin and ALA-PDT had synergistic effect on cSCC, but whether acitretin can enhance the cytotoxic effect of ALA-PDT on cSCC is unclear. OBJECTIVE: To investigate whether acitretin can enhance the cytotoxic effect of ALA-PDT on SCL-1 cells, as well as the possible mechanism involved. METHODS: Inverted microscopy, trypan blue exclusion assay, and flow cytometry were used to studied the morphology, viability and apoptosis of SCL-1 cells treated with acitretin, ALA-PDT and acitretin followed by ALA-PDT treatment, respectively. Confocal microscopy was applied to detect the ROS formation of SCL-1 cells treated with acitretin of four different concentrations. The ROS formation of SCL-I cells treated with acitretin of four different concentrations followed by ALA-PDT treatment was detected using confocal microscopy and flow cytometry. RESULTS: SCL-1 cells exhibited a significant morphological alteration when treated with acitretin followed by ALA-PDT. The combination of acitretin and ALA-PDT induced a higher cell death rate and apoptosis than that with acitretin or ALA-PDT treatment alone. ROS could be induced when incubated with acitretin at a concentration of 6.4 × 10-4mg /mL or above. However, a higher level of ROS formation was observed when SCL-1 cells were treated with acitretin followed by ALA-PDT than that with ALA-PDT or acitretin alone. CONCLUSION: Acitretin can enhance the cytotoxic effect of ALA-PDT on SCL-1 cells, possibly via the ROS pathway.

Regulatory Effect of Adipose-Derived Mesenchymal Stem Cells and/ or Acitretin on Adam10 Gene in Alzheimer's Disease Rat Model.

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by progressive cognitive deterioration. All recent therapeutic strategies tend to inhibit the generation of the Aß peptide. These approaches tend to mediate both α - and γ -secretases to undergo the nonamyloidogenic pathway. ADAM10 is the main α-secretase that cleaves APP, and it is regulated by the metabolic product of vitamin A (retinoic acid), which is being widely used recently in AD research as a target for treatment. Mesenchymal stem cells (MSCs) are also used recently as a promising regenerative therapy for AD. OBJECTIVES: The present study aimed to: (1) study the effect of MSCs with/without acitretin on the regulation of Adam10 gene expression in AlCl3-induced AD rat model, and (2) validate the hypothesis that AD is a time-dependent progressive disease that spreads spontaneously even after the stopping of exposure to AlCl3. METHODS: The experimental work has been designed to include three successive phases; AlCl3 induction phase (I), AlCl3 withdrawal phase (W), and therapeutic phase (T). Forty-five male albino Wistar rats were randomly divided into 2 main groups: the control (C) group (15 rats) and AD group (30 rats). The therapeutic potential of MSCs with/without acitretin has been evaluated at behavioral, physiological, molecular, and histopathological levels. RESULTS: Among the three therapeutic groups, combined administration of both MSC and acitretin showed the best compensatory effects on most of the measured parameters. CONCLUSION: The present study approved that AD is a time-dependent progressive disease which spreads spontaneously without more AlCl3 exposure.

Mechanism of acitretin-induced relaxations in isolated rat thoracic aorta preparations.

Acitretin is a member of vitamin A-derived retinoids, and its effect on vascular smooth muscle had not yet been studied. The aim of this study is to investigate the effect of acitretin, a retinoid, on vascular smooth muscle contractility. Thoracic aorta preparations obtained from 34 male Sprague-Dawley rats (355 ± 15 g) were studied in isolated organ baths containing Krebs-Henseleit solution. The relaxation responses were obtained with acitretin (10-12-10-4 M) in endothelium-preserved and endothelium-denuded aorta preparations precontracted with submaximal concentration of phenylephrine (10-6 M). The role of retinoic acid receptors (RARs), nitric oxide, adenylyl, and guanylyl cyclase enzymes, and potassium channels in these relaxation responses were investigated. Acitretin produced concentration-dependent relaxations, which were independent of its solvent dimethylsulfoxide (DMSO), in endothelium-denuded phenylephrine-precontracted thoracic aorta preparations. While incubation with the RAR antagonist (AGN193109, 10-5 M) had no effect on these relaxations; nitric oxide synthase inhibitor (L-NG-Nitro arginine methyl ester (L-NAME), 10-4 M), adenylyl cyclase inhibitor (SQ2253, 10-5 M), guanylyl cyclase inhibitor (oxadiazolo [4,3-a] quinoxalin-1-one (ODQ), 10-6 M), and potassium channel blocker (tetraethylammonium (TEA), 10-2 M) significantly eliminated the relaxation responses induced by acitretin. Acitretin induces relaxation in rat isolated thoracic aorta preparations without endothelium, which may be mediated by nitric oxide, cyclic adenosine monophosphate, and cyclic guanosine monophosphate-dependent kinases and potassium channels.

IL-22 Downregulates Peptidylarginine Deiminase-1 in Human Keratinocytes: Adding Another Piece to the IL-22 Puzzle in Epidermal Barrier Formation.

Increased presence of IL-22+ cells in the skin is a characteristic finding in skin barrier defects, such as psoriasis and atopic dermatitis. However, mechanistic insight into effects of IL-22 on epidermal functioning is yet to be elucidated. One crucial step during epidermal differentiation is deimination or citrullination. Here, we show reduced levels of peptidylarginine deiminase 1, an enzyme that converts peptidylarginine into citrulline in lesional psoriatic skin. IL-22 signaling through the IL-22 receptor complex was found to suppress expression of peptidylarginine deiminase 1 in epidermal keratinocytes. Subsequently, total peptidylarginine deiminase activity and extent of protein deimination in keratinocytes treated with IL-22 were reduced together with a significant decrease in deimination of keratin 1 and FLG, both important for epidermal differentiation. Vitamin D and acitretin partly restored the peptidylarginine deiminase 1 defect caused by IL-22. Collectively, we show that IL-22 downregulates deimination, thus identifying a potential target for treatment of skin barrier defects.

Shotgun lipidomics of liver and brain tissue of Alzheimer's disease model mice treated with acitretin.

Alzheimer's disease (AD) is a very frequent neurodegenerative disorder characterized by an accumulation of amyloid-ß (Aß). Acitretin, a retinoid-derivative and approved treatment for Psoriasis vulgaris, increases non-amyloidogenic Amyloid-Precursor-Protein-(APP)-processing, prevents Aß-production and elicits cognitive improvement in AD mouse models. As an unintended side effect, acitretin could result in hyperlipidemia. Here, we analyzed the impact of acitretin on the lipidome in brain and liver tissue in the 5xFAD mouse-model. In line with literature, triglycerides were increased in liver accompanied by increased PCaa, plasmalogens and acyl-carnitines, whereas SM-species were decreased. In brain, these effects were partially enhanced or similar but also inverted. While for SM and plasmalogens similar effects were found, PCaa, TAG and acyl-carnitines showed an inverse effect in both tissues. Our findings emphasize, that potential pharmaceuticals to treat AD should be carefully monitored with respect to lipid-homeostasis because APP-processing itself modulates lipid-metabolism and medication might result in further and unexpected changes. Moreover, deducing effects of brain lipid-homeostasis from results obtained for other tissues should be considered cautiously. With respect to acitretin, the increase in brain plasmalogens might display a further positive probability in AD-treatment, while other results, such as decreased SM, indicate the need of medical surveillance for treated patients.

Acitretin mitigates uroporphyrin-induced bone defects in congenital erythropoietic porphyria models.

Congenital erythropoietic porphyria (CEP) is a rare genetic disorder leading to accumulation of uro/coproporphyrin-I in tissues due to inhibition of uroporphyrinogen-III synthase. Clinical manifestations of CEP include bone fragility, severe photosensitivity and photomutilation. Currently there is no specific treatment for CEP, except bone marrow transplantation, and there is an unmet need for treating this orphan disease. Fluorescent porphyrins cause protein aggregation, which led us to hypothesize that uroporphyrin-I accumulation leads to protein aggregation and CEP-related bone phenotype. We developed a zebrafish model that phenocopies features of CEP. As in human patients, uroporphyrin-I accumulated in the bones of zebrafish, leading to impaired bone development. Furthermore, in an osteoblast-like cell line, uroporphyrin-I decreased mineralization, aggregated bone matrix proteins, activated endoplasmic reticulum stress and disrupted autophagy. Using high-throughput drug screening, we identified acitretin, a second-generation retinoid, and showed that it reduced uroporphyrin-I accumulation and its deleterious effects on bones. Our findings provide a new CEP experimental model and a potential repurposed therapeutic.

Retinoic acid signaling is critical during the totipotency window in early mammalian development.

Totipotent cells hold enormous potential for regenerative medicine. Thus, the development of cellular models recapitulating totipotent-like features is of paramount importance. Cells resembling the totipotent cells of early embryos arise spontaneously in mouse embryonic stem (ES) cell cultures. Such '2-cell-like-cells' (2CLCs) recapitulate 2-cell-stage features and display expanded cell potential. Here, we used 2CLCs to perform a small-molecule screen to identify new pathways regulating the 2-cell-stage program. We identified retinoids as robust inducers of 2CLCs and the retinoic acid (RA)-signaling pathway as a key component of the regulatory circuitry of totipotent cells in embryos. Using single-cell RNA-seq, we reveal the transcriptional dynamics of 2CLC reprogramming and show that ES cells undergo distinct cellular trajectories in response to RA. Importantly, endogenous RA activity in early embryos is essential for zygotic genome activation and developmental progression. Overall, our data shed light on the gene regulatory networks controlling cellular plasticity and the totipotency program.

Circulating microRNA profile unveils mechanisms of action of acitretin for psoriasis vulgaris.

Psoriasis vulgaris is a common chronic and recurrent inflammatory skin disease. In clinical practice, acitretin is the first-line treatment drug for psoriasis vulgaris. MicroRNAs (miRNAs) play a vital role in the initiation and development of psoriasis vulgaris. However few studies focused on the mechanisms of acitretin in the treatment of psoriasis vulgaris from the perspective of miRNAs. Here, the expression profiles of circulating miRNAs in the plasma of 12 patients with psoriasis vulgaris before and after acitretin treatment were sequenced. Three miRNAs (miR-146a-5p, miR-122-5p and miR-21-5p) were identified using expression pattern analysis, and the levels were significantly decreased after acitretin treatment (P< 0.001). Receiver operating characteristic (ROC) analyses indicated that the three miRNAs have the potential to be utilized as molecular markers to evaluate the therapeutic effect of acitretin, and the values of the area under the curve (AUC) were 0.825, 0.831, and 0.796, respectively. In addition, we predicted target genes of the three miRNAs and performed signaling pathway enrichment analyses. The results demonstrated that the target genes were mainly involved in the MAPK, JAK-STAT, and NF-κB signaling pathways, which were further validated through in vitro experiments. In conclusion, acitretin can suppress miRNA-mediated MAPK, JAK-STAT, and NF-κB signaling pathways by decreasing miRNAs expression, thereby inhibiting the proliferation and inflammatory response of keratinocytes.

Acitretin and Retinoic Acid Derivatives Inhibit BK Polyomavirus Replication in Primary Human Proximal Renal Tubular Epithelial and Urothelial Cells.

Small-molecule drugs inhibiting BK polyomavirus (BKPyV) represent a significant unmet clinical need in view of polyomavirus-associated nephropathy or hemorrhagic cystitis, which complicate 5% to 25% of kidney and hematopoietic cell transplantations. We characterized the inhibitory activity of acitretin on BKPyV replication in primary human renal proximal tubular epithelial cells (RPTECs). Effective inhibitory concentrations of 50% (EC50) and 90% (EC90) were determined in dilution series measuring BKPyV loads, transcripts, and protein expression, using cell proliferation, metabolic activity, and viability to estimate cytotoxic concentrations and selectivity indices (SI). The acitretin EC50 and EC90 in RPTECs were 0.64 (SI50, 250) and 3.25 µM (SI90, 49.2), respectively. Acitretin effectively inhibited BKPyV replication until 72 h postinfection when added 24 h before infection until 12 h after infection, but decreased to <50% at later time points. Acitretin did not interfere with nuclear delivery of BKPyV genomes, but it decreased large T-antigen transcription and protein expression. Acitretin did not inhibit the initial round of BKPyV replication following transfection of full-length viral genomes, but it affected subsequent rounds of reinfection. Acitretin also inhibited BKPyV replication in human urothelial cells and in Vero cells, but not in COS-7 cells constitutively expressing Simian virus 40 (SV40) large T antigen. Retinoic acid agonists (all-trans retinoic acid, 9-cis retinoic acid [9-cis-RA], 13-cis-RA, bexarotene, and tamibarotene) and the RAR/RXR antagonist RO41-5253 also inhibited BKPyV replication, pointing to an as-yet-undefined mechanism. IMPORTANCE Acitretin selectively inhibits BKPyV replication in primary human cell culture models of nephropathy and hemorrhagic cystitis. Since acitretin is an approved drug in clinical use reaching BKPyV-inhibiting concentrations in systemically treated patients, further studies are warranted to provide data for clinical repurposing of retinoids for treatment and prevention of replicative BKPyV-diseases.

Acitretin reverses early functional network degradation in a mouse model of familial Alzheimer's disease.

Aberrant activity of local functional networks underlies memory and cognition deficits in Alzheimer's disease (AD). Hyperactivity was observed in microcircuits of mice AD-models showing plaques, and also recently in early stage AD mutants prior to amyloid deposition. However, early functional effects of AD on cortical microcircuits remain unresolved. Using two-photon calcium imaging, we found altered temporal distributions (burstiness) in the spontaneous activity of layer II/III visual cortex neurons, in a mouse model of familial Alzheimer's disease (5xFAD), before plaque formation. Graph theory (GT) measures revealed a distinct network topology of 5xFAD microcircuits, as compared to healthy controls, suggesting degradation of parameters related to network robustness. After treatment with acitretin, we observed a re-balancing of those network measures in 5xFAD mice; particularly in the mean degree distribution, related to network development and resilience, and post-treatment values resembled those of age-matched controls. Further, behavioral deficits, and the increase of excitatory synapse numbers in layer II/III were reversed after treatment. GT is widely applied for whole-brain network analysis in human neuroimaging, we here demonstrate the translational value of GT as a multi-level tool, to probe networks at different levels in order to assess treatments, explore mechanisms, and contribute to early diagnosis.

Repurposing Acitretin as an Antipseudomonal Agent Targeting the Pseudomonas aeruginosa Iron-Regulated Heme Oxygenase.

Iron is an essential micronutrient for the survival and virulence of the bacterial pathogen Pseudomonas aeruginosa. To overcome iron withholding and successfully colonize a host, P. aeruginosa uses a variety of mechanisms to acquire iron, including the secretion of high-affinity iron chelators (siderophores) or the uptake and utilization of heme. P. aeruginosa heme oxygenase (HemO) plays pivotal roles in heme sensing, uptake, and utilization and has emerged as a therapeutic target for the development of antipseudomonal agents. Using a high-throughput fluorescence quenching assay combined with minimum inhibitory concentration measurements, we screened the Selleck Bioactive collection of 2100 compounds and identified acitretin, a Food and Drug Administration-approved oral retinoid, as a potent and selective inhibitor of HemO. Acitretin binds to HemO with a KD value of 0.10 ± 0.02 µM and inhibits the growth of P. aeruginosa PAO1 with an IC50 of 70 ± 18 µg/mL. In addition, acitretin showed good selectivity for HemO, which uniquely generates BVIXß/δ, over human heme oxygenase (hHO1) and other BVIXα-producing homologues such as the heme oxygenases from Neisseria meningitidis (nmHO) and Acinetobacter baumannii (abHO). The binding of acitretin within the HemO active site was confirmed by 1H-15N heteronuclear single-quantum coherence nuclear magnetic resonance, and molecular modeling provided further insight into potential interactions of acitretin with residues specific for orienting heme in the ß/δ selective HemO. Moreover, at 20 µM, acitretin inhibited the enzymatic activity of HemO in P. aeruginosa cells by >60% and effectively blocked the ability of P. aeruginosa to sense and acquire heme as demonstrated in the ß-galactosidase transcriptional reporter assay.

Topical Aminosalicylic Acid Improves Keratinocyte Differentiation in an Inducible Mouse Model of Harlequin Ichthyosis.

Mutations in the lipid transport protein ABCA12 cause the life-threatening skin condition harlequin ichthyosis (HI), which is characterized by the loss of skin barrier function, inflammation, and dehydration. Inflammatory responses in HI increase disease severity by impairing keratinocyte differentiation, suggesting amelioration of this phenotype as a possible therapy for the condition. Existing treatments for HI are based around the use of retinoids, but their value in treating patients during the neonatal period has been questioned relative to other improved management regimens, and their long-term use is associated with side effects. We have developed a conditional mouse model to demonstrate that topical application of the aminosalicylic acid derivatives 5ASA or 4ASA considerably improves HI keratinocyte differentiation without the undesirable side effects of the retinoid acitretin and salicylic acid (aspirin). Analysis of changes in gene expression shows that 4ASA in particular elicits compensatory upregulation of a large family of barrier function-related genes, many of which are associated with other ichthyoses, identifying this compound as a lead candidate for developing topical treatments for HI.

5-aminolevulinic acid photodynamic therapy enhance the effect of acitretin on squamous cell carcinoma cells: An in vitro study.

Squamous cell carcinoma (SCC) remains the second most common nonmelanoma skin cancer (NMSC) worldwide. Both acitretin and 5-Aminolevulinic acid mediated photodynamic therapy (ALA-PDT) have validated effect on SCC. However, the effects of both treatmens remain limited, and there has been no report concerning the potential synergistic effect of both treatments for SCC. OBJECTIVE: To investigate the cytotoxic effect of acitretin on SCL-1 cells, and whether ALA-PDT enhances this effect. METHODS: CCK-8 and trypan blue exclusion array were used to detect the cell cytotoxicity after acitretin treatment with different concentrations (1.6 × 10-4mg/mL, 1.6 × 10-3 mg/mL, 1.6 × 10-2mg/mL and 1.6 × 10-1mg/mL) for 24 h, 48 h and 72 h. Flow cytometry and trypan blue exclusion assay were used to detect the apoptosis and viability of SCL-1 cells after treated with acitretin, ALA-PDT and ALA-PDT immediately followed by acitretin. Independent sample t test was used to analyze the different incubation time of acitretin and acitretin combined with ALA-PDT on SCL-1 cells. Bonferroni Test One-way Anova method was used to analyze the effect of different treatment on the SCL-1 cells. RESULTS: A significant cytotoxic effect was observed after acitretin treatment, in an acitretin concentration-dependent manner within the range of 1.6 × 10-4mg/mL to 1.6 × 10-1mg/mL and an acitretin incubation time-dependent manner within 24 h-72 h. The total apoptosis rate and dead cells rate in group of ALA-PDT combined with acitretin were both significantly higher than that of acitretin, ALA-PDT group. A stronger apoptotic and cytotoxic effect detected 24 h after treated with acitretin than that of 12 h was observed in this study. CONCLUSION: Acitretin has a cytotoxic effect on SCL-1 cells, and ALA-PDT treatment enhances the the cytotoxic effect of acitretin.