Combination of everolimus and tacrolimus: a potentially effective regimen for recalcitrant psoriasis

Systemic calcineurin inhibitors tacrolimus and voclosporin: A review of off-label dermatologic uses

BACKGROUND

Systemic calcineurin inhibitors, cyclosporine, tacrolimus, and voclosporin, have been utilized in various dermatologic conditions. Although there have been numerous off-label dermatologic indications with published guidelines for cyclosporine, there is no established strong consensus for tacrolimus and voclosporin.

OBJECTIVE

To conduct a review of off-label use of systemic tacrolimus and voclosporin in various dermatoses to better inform treatment methods.

METHODS

A literature search was conducted using PubMed and Google Scholar. Relevant clinical trials, observational studies, case series, and reports regarding off-label dermatologic uses of systemic tacrolimus and voclosporin were included.

RESULTS

Tacrolimus shows promise for numerous dermatologic conditions, including psoriasis, atopic dermatitis/eczema, pyoderma gangrenosum, chronic urticaria, and Behcet's disease. Randomized controlled trial data are only available for voclosporin in psoriasis, which showed efficacy but did not meet noninferiority to cyclosporine.

LIMITATIONS

Data were limited and extracted from published papers. Studies differed in methodology, and nonstandardized outcomes limited the conclusions drawn.

CONCLUSIONS

In comparison to cyclosporine, tacrolimus can be considered for treatment-refractory disease or in patients with cardiovascular risk factors or inflammatory bowel disease. Voclosporin has only been utilized in psoriasis currently, and clinical trials in psoriasis show voclosporin's efficacy. Voclosporin can be considered for patients with lupus nephritis.

Psoriasis in the transplant population

Solid organ and stem cell transplants are increasingly common, and dermatologists will more frequently encounter and need to manage common skin diseases, such as psoriasis, in transplant patients. This review explores psoriasis remission and occurrence in recipients of solid organ and stem cell transplants. Hematopoietic and mesenchymal stem cell transplants may show potential for treating psoriasis in patients with leukemia or who have other medical conditions requiring stem cell transplant. The effects of solid organ transplant are less clear, partly due to limitations in the breadth of the literature. De novo psoriasis has been reported in recipients of solid organ transplants, but the reasons for this development have yet to be fully understood. Overall, the literature on this subject is limited to primarily case reports. Feasibility of studies on the subject may be a considerable barrier to further research assessing the use of transplant for treating psoriasis, but there is potential benefit from transplant for psoriasis patients. This subject should receive further exploration to fully understand these benefits.

The PI3K-Akt-mTOR and Associated Signaling Pathways as Molecular Drivers of Immune-Mediated Inflammatory Skin Diseases: Update on Therapeutic Strategy Using Natural and Synthetic Compounds

The dysregulated phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) signaling pathway has been implicated in various immune-mediated inflammatory and hyperproliferative dermatoses such as acne, atopic dermatitis, alopecia, psoriasis, wounds, and vitiligo, and is associated with poor treatment outcomes. Improved comprehension of the consequences of the dysregulated PI3K/Akt/mTOR pathway in patients with inflammatory dermatoses has resulted in the development of novel therapeutic approaches. Nonetheless, more studies are necessary to validate the regulatory role of this pathway and to create more effective preventive and treatment methods for a wide range of inflammatory skin diseases. Several studies have revealed that certain natural products and synthetic compounds can obstruct the expression/activity of PI3K/Akt/mTOR, underscoring their potential in managing common and persistent skin inflammatory disorders. This review summarizes recent advances in understanding the role of the activated PI3K/Akt/mTOR pathway and associated components in immune-mediated inflammatory dermatoses and discusses the potential of bioactive natural products, synthetic scaffolds, and biologic agents in their prevention and treatment. However, further research is necessary to validate the regulatory role of this pathway and develop more effective therapies for inflammatory skin disorders.

Molecular treatment trajectories within psoriatic T lymphocytes: a mini review

Multiple biological processes in mammalian cells are implicated in psoriasis (Ps) development and progression, as well as in the pathogenic mechanisms associated with this chronic immune-mediated inflammatory disease (IMID). These refer to molecular cascades contributing to the pathological topical and systemic reactions in Ps, where local skin-resident cells derived from peripheral blood and skin-infiltrating cells originating from the circulatory system, in particular T lymphocytes (T cells), are key actors. The interplay between molecular components of T cell signalling transduction and their involvement in cellular cascades (i.e. throughout Ca²⁺/CaN/NFAT, MAPK/JNK, PI3K/Akt/mTOR, JAK/STAT pathways) has been of concern in the last few years; this is still less characterised than expected, even though some evidence has accumulated to date identifying them as potential objects in the management of Ps. Innovative therapeutic strategies for the use of compounds such as synthetic Small Molecule Drugs (SMDs) and their various combinations proved to be promising tools for the treatment of Ps via incomplete blocking, also known as modulation of disease-associated molecular tracks. Despite recent drug development having mainly centred on biological therapies for Ps, yet displaying serious limitations, SMDs acting on specific pathway factor isoforms or single effectors within T cell, could represent a valid innovation in real-world treatment patterns in patients with Ps. Of note, due to the intricate crosstalk between intracellular pathways, the use of selective agents targeting proper tracks is, in our opinion, a challenge for modern science regarding the prevention of disease at its onset and also in the prediction of patient response to Ps treatment.

Dual targeting of mTOR/IL-17A and autophagy by fisetin alleviates psoriasis-like skin inflammation

Psoriasis is a chronic autoimmune inflammatory skin disorder characterized by epidermal hyperplasia and aberrant immune response. In addition to aberrant cytokine production, psoriasis is associated with activation of the Akt/mTOR pathway. mTOR/S6K1 regulates T-lymphocyte activation and migration, keratinocytes proliferation and is upregulated in psoriatic lesions. Several drugs that target Th1/Th17 cytokines or their receptors have been approved for treating psoriasis in humans with variable results necessitating improved therapies. Fisetin, a natural dietary polyphenol with anti-oxidant and anti-proliferative properties, covalently binds mTOR/S6K1. The effects of fisetin on psoriasis and its underlying mechanisms have not been clearly defined. Here, we evaluated the immunomodulatory effects of fisetin on Th1/Th17-cytokine-activated adult human epidermal keratinocytes (HEKa) and anti-CD3/CD28-stimulated inflammatory CD4+ T cells and compared these activities with those of rapamycin (an mTOR inhibitor). Transcriptomic analysis of HEKa revealed 12,713 differentially expressed genes (DEGs) in the fisetin-treated group compared to 7,374 DEGs in the rapamycin-treated group, both individually compared to a cytokine treated group. Gene ontology analysis revealed enriched functional groups related to PI3K/Akt/mTOR signaling pathways, psoriasis, and epidermal development. Using in silico molecular modeling, we observed a high binding affinity of fisetin to IL-17A. In vitro, fisetin significantly inhibited mTOR activity, increased the expression of autophagy markers LC3A/B and Atg5 in HEKa cells and suppressed the secretion of IL-17A by activated CD4+ T lymphocytes or T lymphocytes co-cultured with HEKa. Topical administration of fisetin in an imiquimod (IMQ)-induced mouse psoriasis model exhibited a better effect than rapamycin in reducing psoriasis-like inflammation and Akt/mTOR phosphorylation and promoting keratinocyte differentiation and autophagy in mice skin lesions. Fisetin also significantly inhibited T-lymphocytes and F4/80+ macrophage infiltration into skin. We conclude that fisetin potently inhibits IL-17A and the Akt/mTOR pathway and promotes keratinocyte differentiation and autophagy to alleviate IMQ-induced psoriasis-like disease in mice. Altogether, our findings suggest fisetin as a potential treatment for psoriasis and possibly other inflammatory skin diseases.

mTORC1 Activity in Psoriatic Lesions Is Mediated by Aberrant Regulation through the Tuberous Sclerosis Complex

In the basal, proliferative layer of healthy skin, the mTOR complex 1 (mTORC1) is activated, thus regulating proliferation while preventing differentiation. When cells leave the proliferative, basal compartment, mTORC1 signaling is turned off, which allows differentiation. Under inflammatory conditions, this switch is hijacked by cytokines and prevents proper differentiation. It is currently unknown how mTORC1 is regulated to mediate these effects on keratinocyte differentiation. In other tissues, mTORC1 activity is controlled through various pathways via the tuberous sclerosis complex (TSC). Thus, we investigated whether the TS complex is regulated by proinflammatory cytokines and contributes to the pathogenesis of psoriasis. TNF-α as well as IL-1β induced the phosphorylation of TSC2, especially on S939 via the PI3-K/AKT and MAPK pathway. Surprisingly, increased TSC2 phosphorylation could not be detected in psoriasis patients. Instead, TSC2 was strongly downregulated in lesional psoriatic skin compared to non-lesional skin of the same patients or healthy skin. In vitro inflammatory cytokines induced dissociation of TSC2 from the lysosome, followed by destabilization of the TS complex and degradation. Thus, we assume that in psoriasis, inflammatory cytokines induce strong TSC2 phosphorylation, which in turn leads to its degradation. Consequently, chronic mTORC1 activity impairs ordered keratinocyte differentiation and contributes to the phenotypical changes seen in the psoriatic epidermis.

Novel Therapeutic Target(s) for Psoriatic Disease

Psoriasis and psoriatic arthritis, together known as psoriatic disease, is highly prevalent chronic relapsing inflammatory disease affecting skin, joints or both and is associated with several comorbidities such as cardiovascular, metabolic, psychiatric, renal disease etc. The etiopathogenesis of psoriasis is complex and mainly driven by aberrant immune response owing to the genetic susceptibility and various environmental factors such as trauma, infections and drugs. Recent advances in understanding molecular and cellular pathways have identified tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), IL-23, IL-22 as major contributors in psoriasis pathogenesis. Advances in the knowledge of pathophysiology, the interaction of autoinflammation and clinical phenotypes have led to the development of highly effective targeted therapeutic agents which include TNF-α, IL-17, IL-23, IL-1 α/β or IL-36 inhibitors or receptor blockers, small molecule drugs like phosphodiesterase-4 inhibitors (apremilast), Janus kinase (JAK) inhibitors, retinoic acid receptor-related orphan receptor γt (RORγt) inhibitors. These novel drugs have promised the potential of improved disease control. In recent years, the transition from biologics to biosimilars especially with TNF-α inhibitors had significant impact on decreasing health care cost and increasing therapeutic options to the patients. However, selection of right treatment for an individual patient still remains challenging. Moreover, interplay between different epigenetic mechanisms such as the DNA methylation, chromatin modifications and noncoding RNA regulation has recently been started to be deciphered. Enzymes inhibitors involved in epigenetic pathways such as DNA methyltransferases and histone deacetylases demonstrated to restore normal epigenetic patterns in clinical settings and have provided the potential as novel therapeutic targets for psoriasis. In this review, we will discuss novel biologic agents and newer therapeutic approaches in treatment of psoriatic disease.

Predominant Role of mTOR Signaling in Skin Diseases with Therapeutic Potential

The serine/threonine kinase mechanistic target of rapamycin (mTOR) plays a pivotal role in the regulation of cell proliferation, survival, and motility in response to availability of energy and nutrients as well as mitogens. The mTOR signaling axis regulates important biological processes, including cellular growth, metabolism, and survival in many tissues. In the skin, dysregulation of PI3K/AKT/mTOR pathway may lead to severe pathological conditions characterized by uncontrolled proliferation and inflammation, including skin hyperproliferative as well as malignant diseases. Herein, we provide an update on the current knowledge regarding the pathogenic implication of the mTOR pathway in skin diseases with inflammatory features (such as psoriasis, atopic dermatitis, pemphigus, and acne) and malignant characteristics (such as cutaneous T cell lymphoma and melanoma) while we critically discuss current and future perspectives for therapeutic targeting of mTOR axis in clinical practice.

Rapamycin Alleviates 2,3,7,8-Tetrachlorodibenzo-p-dioxin-Induced Aggravated Dermatitis in Mice with Imiquimod-Induced Psoriasis-Like Dermatitis by Inducing Autophagy

Recently, the mTOR signaling has emerged as an important player in the pathogenesis of psoriasis. We previously found that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced psoriatic skin inflammation was related to the inhibition of autophagy in keratinocytes. However, the effects and detailed molecular mechanisms of the mTOR inhibitor rapamycin and TCDD on psoriasis in vivo remain to be elucidated. In this study, we aimed to evaluate the effects of rapamycin and TCDD on skin lesions in imiquimod (IMQ)-induced psoriasis using a mouse model. TCDD aggravated skin inflammation in an IMQ-induced psoriatic mouse model. Furthermore, TCDD increased the expression of aryl hydrocarbon receptor (AHR), CYP1A1, proinflammatory cytokines, oxidative stress markers (NADPH oxidase (Nox) 2, Nox4), and phosphorylated P65NF-ĸB, whereas the expression of autophagy-related factors and the antioxidant marker nuclear factor-erythroid 2-related factor 2 (NRF2) decreased. Rapamycin reduced the aggravated skin inflammation induced by TCDD and restored TCDD-induced autophagy suppression and the increase of AHR expression, oxidative stress, and inflammatory response in the skin lesions of a psoriatic mouse model. In conclusion, we demonstrated that rapamycin alleviates TCDD-induced aggravated dermatitis in mice with imiquimod-induced psoriasis-like dermatitis through AHR and autophagy modulation.

Engineered antigen-specific regulatory T cells for autoimmune skin conditions

Regulatory T cells (Tregs) are a subset of T cells responsible for the regulation of immune responses, thereby maintaining immune homeostasis and providing immune tolerance to both self and non-self-antigens. An increasing number of studies revealed Treg numbers and functions in a variety of autoimmune diseases. Treg deficiency can cause the development of several autoimmune skin diseases including vitiligo, alopecia areata, pemphigoid and pemphigus, psoriasis, and systemic sclerosis. Many clinical trials have been performed for autoimmune conditions using polyclonal Tregs, but efficiency can be significantly improved using antigen-specific Tregs engineered using T cell receptor (TCR) or chimeric antigen receptor (CAR) constructs. In this review, we systematically reviewed altered frequencies, impaired functions, and phenotypic features of Tregs in autoimmune skin conditions. We also summarized new advances in TCR and CAR based antigen-specific Tregs tested both in animal models and in clinics. The advantages and limitations of each approach were carefully discussed emphasizing possible clinical relevance to patients with autoimmune skin diseases. Moreover, we have reviewed potential approaches for engineering antigen-specific Tregs, and strategies for overcoming possible hurdles in clinical applications. Thereby, antigen-specific Tregs can be infused using autologous adoptive cell transfer to restore Treg numbers and to provide local immune tolerance for autoimmune skin disorders.

Differential Roles of the mTOR-STAT3 Signaling in Dermal γδ T Cell Effector Function in Skin Inflammation

Dermal γδT cells play critical roles in skin homeostasis and inflammation. However, the underlying molecular mechanisms by which these cells are activated have not been fully understood. Here, we show that the mechanistic or mammalian target of rapamycin (mTOR) and STAT3 pathways are activated in dermal γδT cells in response to innate stimuli such as interleukin-1β (IL-1β) and IL-23. Although both mTOR complex 1 (mTORC1) and mTORC2 are essential for dermal γδT cell proliferation, mTORC2 deficiency leads to decreased dermal γδT17 cells. It appears that mitochondria-mediated oxidative phosphorylation is critical in this process. Notably, although the STAT3 pathway is critical for dermal Vγ4T17 effector function, it is not required for γδ6T17 cells. Transcription factor IRF-4 activation promotes dermal γδT cell IL-17 production by linking IL-1β and IL-23 signaling. The absence of mTORC2 in dermal γδT cells, but not STAT3, ameliorates skin inflammation. Taken together, our results demonstrate that the mTOR-STAT3 signaling differentially regulates dermal γδT cell effector function in skin inflammation.

Cai et al. demonstrate that the mTOR and STAT3 signaling pathways differentially regulate dermal Vγ4 and Vγ6 T cell effector function, leading to distinct outcomes in skin inflammation.

Updated therapies for the management of Psoriatic Arthritis

Psoriatic arthritis (PsA) is a large volume of our clinical practice and its management can be challenging. Traditional DMARDs have been used over last six decades and observational studies have substantiated an effective use of many of these drugs. However, in last two decades use of anti-TNF agents has brought a new dimension in treatment of PsA and in many other autoimmune diseases. Regulatory role of the Th17 cells and its cytokines in the pathogenesis of PsA has successfully paved the foundations of anti-IL antibody based therapies in PsA. Newer therapies targeting the IL-23/IL-17 cytokines and its signaling proteins are now in development and bringing new promises for management of PsA. Herein, we provide an overview of the landscape of drug therapies, including IL-17, IL-12/23, IL-23 inhibitors, and janus kinase (JAK) inhibitors, as well as those in development, such as RORγt inhibitors, anti-NGF agents, mTOR inhibitors and T cell ion-channel blockers.

Impact of Minor Structural Modifications on Properties of a Series of mTOR Inhibitors

Minor structural modifications-sometimes single atom changes-can have a dramatic impact on the properties of compounds. This is illustrated here on structures related to known mTOR inhibitor Sapanisertib. Subtle changes in the hinge binder lead to strikingly different overall profiles with changes in physical properties, metabolism, and kinase selectivity.

Epidermal mTORC1 Signaling Contributes to the Pathogenesis of Psoriasis and Could Serve as a Therapeutic Target

Although modern biologics targeting different inflammatory mediators show promising therapeutic success, comprehensive knowledge about the molecular events in psoriatic keratinocytes that contribute to the pathogenesis and could serve as therapeutic targets is still scarce. However, recent efforts to understand the deregulated signal transduction pathways have led to the development of small molecule inhibitors e.g., tofacitinib targeting the Jak/Stat cascade that opens additional therapeutic options. Recently, the PI3-K/Akt/mTOR signaling pathway has emerged as an important player in the control of epidermal homeostasis. This review summarizes the current knowledge on the role of this pathway in the pathogenesis of psoriasis, especially the epidermal manifestation of the disease and discusses current approaches to target the pathway therapeutically.

Polycystin-1 downregulation induces ERK-dependent mTOR pathway activation in a cellular model of psoriasis

Psoriatic plaques tend to localize to the knees and elbows, areas that are particularly subject to mechanical stress resulting from bending and friction. Moreover, plaques often develop at sites of mechanical trauma or injury (Koebner phenomenon). Nevertheless, mechanotransduction has never been linked to psoriasis. Polycystins (polycystin-1, PC1; polycystin-2, PC2) are mechanosensitive molecules that function as key regulators of cellular mechanosensitivity and mechanotransduction. The aim of this in vitro study was to investigate the role of polycystins in the development of psoriasis. We showed that PC1 knockdown in HaCaT cells led to an elevated mRNA expression of psoriasis-related biomarkers Ki-67, IL-6, TNF-α, VEGF and Bcl-2, while PC1 functional inhibition was accompanied by increased cell proliferation and migration of HaCaT cells. In addition, PC1 knockdown via siRNA in HaCaT cells was followed by activation of critical molecules of the mTOR and MAPK pathways and this mTOR pathway activation was ERK-dependent. Furthermore, loss of PC1 protein expression and elevated levels of activated mTOR substrates were also observed in human samples of psoriatic plaques. Overall, our study suggests that the PC1/ERK/mTOR signaling axis represents a novel potential mechanism in psoriasis pathogenesis.

Active natural oil-based nanoemulsion containing tacrolimus for synergistic antipsoriatic efficacy

AIM

The current study is emphasized on development of a nanoemulsion system that simultaneously delivers two antipsoriatic agents viz. Tacrolimus and Kalonji oil (functional excepient) topically.

MATERIALS & METHODS

A nanoemulsion was characterized for quality attributes; a nanoemulsion gel was evaluated for spreadability, viscosity, dermal bioavailability, and in vitro efficacy in A-431 cell line, and so forth. In vivo performance was evaluated on psoriasis model in BALB/c mice.

RESULTS

Nanoemulsion depicted droplet size: 93.37 ± 2.58 nm with PDI (Polydispersity Index) 0.330 ± 0.025. The nanoemulsion gel exhibited desirable spreadability with sustained release pattern (biphasic). Dermal bioavailability enhancement (4.33-fold) accompanied significant in vitro results. A significant reduction in serum cytokines and improvement in psoriatic condition was achieved in vivo, indicating formulation efficacy compared with marketed formulation (Tacroz Forte, Glenmark Pharmaceuticals Ltd, Maharashtra, India).

CONCLUSION

Nanoemulsion gel thus provides an effective alternative for psoriasis treatment.

Replenishing Regulatory T Cells to Halt Depigmentation in Vitiligo

Vitiligo is a cutaneous autoimmune disease, especially devastating to patients with darker skin tones because of the contrast between unaffected and lesional skin. We studied immune cells infiltrating vitiligo skin and found very few regulatory T cells (Tregs). Vitiligo was not associated with a reduced frequency or function of circulating Tregs. To manipulate Treg function, we used mouse models expressing melanocyte-reactive TCRs, following changes in pelage color. We also isolated splenocytes to measure Treg function and evaluated cutaneous Treg abundance. Even small numbers of Tregs transferred into depigmenting mice could effectively interfere with depigmentation. The same holds true for treatment with rapamycin, readily translatable for use in human patients; such treatment may be well tolerated. Because vitiligo skin is relatively devoid of cells that produce the chemokine CCL22, whereas circulating Tregs express normal levels of its receptor CCR4, we overexpressed Ccl22 in the skin of vitiligo-prone mice to assess the resulting levels of depigmentation. Markedly reduced depigmentation was accompanied by Treg infiltration to the skin. With several options available to support a healthy balance between Tregs and effector T cells, the next challenge will be to render such treatment antigen specific and avoid general immunosuppression.

TNF stimulates IL-6, CXCL8 and VEGF secretion from human keratinocytes via activation of mTOR, inhibited by tetramethoxyluteolin

Psoriasis is an autoimmune skin disease characterized by keratinocyte hyperproliferation and chronic inflammation. The pathogenesis of psoriasis involves proinflammatory cytokines, such as tumor necrosis factor (TNF), but the mechanism of keratinocyte activation is not well understood. Here, we show that TNF (10 or 50 ng/mL) stimulates a significant (P < .0001) gene expression and secretion of proinflammatory IL-6, CXCL8 and VEGF from both cultured human HaCaT and normal epidermal human keratinocytes (NHEKs). This effect occurs via activation of the mammalian target of rapamycin (mTOR) signalling complex as shown by Western blot analysis and phospho-ELISAs. Pretreatment with the novel natural flavonoid tetramethoxyluteolin (10-100 μmol L^-1 ) significantly (P < .0001) inhibits gene expression and secretion (P < .0001) of all 3 mediators in a concentration-dependent manner. Moreover, tetramethoxyluteolin (50 μmol L^-1 ) appears to be a potent inhibitor of the phosphorylated mTOR substrates (pmTOR^Ser2448 , pp70S6K^Thr389 and p4EBP1^Thr37/46 ) as compared to known mTOR inhibitors in keratinocytes. The present findings indicate that TNF stimulates skin inflammation via mTOR signalling. Inhibition by tetramethoxyluteolin may be used in the treatment for psoriasis.

Sirolimus treatment for cirrhosis or hepatocellular carcinoma patients accompanied by psoriasis after liver transplantation: A single center experience

There is currently no consensus on the most suitable therapeutic approach for psoriasis (PS) co-existing with posthepatic cirrhosis (PCs) and hepatocellular carcinoma (HCC) following liver transplantation (LT). The present study provides an analysis of the therapeutic experience of such patients. Five LT recipients (two with PC and three with HCC) with accompanying PS were included. The induction program consisted of methylprednisolone plus basiliximab treatment. The initial postoperative treatment scheme consisted of tacrolimus (FK506) plus mycophenolate mofetil (MMF) and hormone; the latter was withdrawn 1 week after LT. The patients with PC had been using FK506 with or without a postoperative MMF program; the patients with HCC and recurrence of PS had been switched to a sirolimus (SRL)-based replacement therapy. Furthermore, all patients received anti-hepatitis B virus (HBV) therapy. The patients were followed up after 8.3±1.5 years. There was a positive correlation between HBV-DNA copy numbers, and psoriatic area and severity index (PASI) scores (r=0.97; P=0.006). The PASI scores were decreased significantly at 6 months following surgery compared with pre-transplantation (P<0.05). The patients who had received the FK506-based treatment experienced PS recurrence two years post-transplantation. The PASI scores increased significantly (P<0.05) and then declined gradually, maintaining a stable level (P<0.05) by 1 year after switching to the SRL-based treatment. The patients who had received the SRL-based treatment exhibited no recurrence of PS. The results of the present study suggest that SRL therapy provides a promising novel treatment method for patients with PS following LT that may be superior to tacrolimus treatment. When co-existing HBV is present pre-transplantation, regular injection of human hepatitis B immunoglobulin should be used to prevent the HBV from relapsing or aggravating the PS.

RHEB1 insufficiency in aged male mice is associated with stress-induced seizures

The mechanistic target of rapamycin (mTOR), a protein kinase, is a central regulator of mammalian metabolism and physiology. Protein mTOR complex 1 (mTORC1) functions as a major sensor for the nutrient, energy, and redox state of a cell and is activated by ras homolog enriched in brain (RHEB1), a GTP-binding protein. Increased activation of mTORC1 pathway has been associated with developmental abnormalities, certain form of epilepsy (tuberous sclerosis), and cancer. Clinically, those mTOR-related disorders are treated with the mTOR inhibitor rapamycin and its rapalogs. Because the effects of chronic interference with mTOR signaling in the aged brain are yet unknown, we used a genetic strategy to interfere with mTORC1 signaling selectively by introducing mutations of Rheb1 into the mouse. We created conventional knockout (Rheb1 ^+/- ) and gene trap (Rheb1 ^Δ/+ ) mutant mouse lines. Rheb1-insufficient mice with different combinations of mutant alleles were monitored over a time span of 2 years. The mice did not show any behavioral/neurological changes during the first 18 months of age. However, after aging (> 18 months of age), both the Rheb1 ^+/- and Rheb1 ^{Δ /-} hybrid males developed rare stress-induced seizures, whereas Rheb1 ^+/- and Rheb1 ^{Δ /-} females and Rheb1 ^Δ/+ and Rheb1 ^Δ/Δ mice of both genders did not show any abnormality. Our findings suggest that chronic intervention with mTORC1 signaling in the aged brain might be associated with major adverse events.

Inflammation dependent mTORC1 signaling interferes with the switch from keratinocyte proliferation to differentiation

Psoriasis is a frequent and often severe inflammatory skin disease, characterized by altered epidermal homeostasis. Since we found previously that Akt/mTOR signaling is hyperactivated in psoriatic skin, we aimed at elucidating the role of aberrant mTORC1 signaling in this disease. We found that under healthy conditions mTOR signaling was shut off when keratinocytes switch from proliferation to terminal differentiation. Inflammatory cytokines (IL-1β, IL-17A, TNF-α) induced aberrant mTOR activity which led to enhanced proliferation and reduced expression of differentiation markers. Conversely, regular differentiation could be restored if mTORC1 signaling was blocked. In mice, activation of mTOR through the agonist MHY1485 also led to aberrant epidermal organization and involucrin distribution. In summary, these results not only identify mTORC1 as an important signal integrator pivotal for the cells fate to either proliferate or differentiate, but emphasize the role of inflammation-dependent mTOR activation as a psoriatic pathomechanism.

Tacrolimus for the management of psoriasis: clinical utility and place in therapy

Psoriasis affects 1%-3% of the population in the United Kingdom and can convey significant detriment to the physical and mental health of sufferers. Plaques of psoriasis typically affect the extensor skin surfaces and scalp. Less frequently inverse psoriasis can affect more sensitive skin such as the face, genitals, and intertriginous areas. Psoriasis is incurable, but there are a range of treatment modalities that can be used to manage the condition. Treatment options include topical preparations, phototherapy, systemic therapy, and biological agents. Tacrolimus is a macrolide calcineurin inhibitor licensed for immunosuppression in transplant patients and topical administration in atopic dermatitis. Tacrolimus administered orally and in topical form has been shown to produce successful outcomes in patients with psoriasis. Topical tacrolimus is particularly effective for inverse psoriasis, which is likely to be due to the reduced level of induration seen in these psoriatic lesions, which allows greater skin penetrance, compared with hyperkeratotic plaques of psoriasis on the body. It is also notable that the areas affected by inverse psoriasis are more susceptible to adverse effects of topical corticosteroid therapy, and thus a topical preparation without the risk of skin atrophy, telangiectasia, and striae could be a valuable addition to current topical treatment options. Oral tacrolimus has shown efficacy in the treatment of severe, refractory psoriasis. Compared to ciclosporin, systemic tacrolimus may be more suited to a patient population with increased cardiovascular risk. This review will draw together the current literature on topical and oral tacrolimus for the treatment of psoriasis. Efficacy and safety have been evaluated by case reports and randomized controlled trials and comparisons have been made between tacrolimus therapy and standard treatment.

Recurrent Psoriasis After Introduction of Belatacept in 2 Kidney Transplant Recipients

Organ transplant recipients may have skin diseases as a result of immunosuppression, but psoriasis is reported infrequently. This skin condition may be induced by immunosuppression imbalance. We present 2 cases of recurrent psoriasis in 2 kidney transplant patients with belatacept-based immunosuppressive regimens. Two years after transplant, upon suspicion of calcineurin inhibitor neurotoxicity in the first patient, tacrolimus was replaced with belatacept. The patient's neurological signs resolved but the patient presented with skin lesions compatible with psoriatic plaques, successfully treated with betamethasone dipropionate and hydrocortisone. The second patient had a history of obesity and dyslipidemia, left foot amputation, and psoriasis. He received a kidney transplant, and maintenance immunosuppression included prednisone, mycophenolate mofetil, and belatacept. At posttransplant month 15, the patient presented with cutaneous erythematosus, maculopapular, and desquamative lesions compatible with psoriasis, treated with betamethasone dipropionate. The belatacept-based immunosuppressive regimens were maintained and psoriasis resolved. Psoriasis is a potential complication in kidney recipients that may recur when belatacept is used and/or tacrolimus is withdrawn as it could have happened in the first patient. The characteristics of the second case may suggest that belatacept might not have been the inciting agent. Good results were obtained with topical treatment.

Metformin inhibits proliferation and proinflammatory cytokines of human keratinocytes in vitro via mTOR-signaling pathway

CONTEXT

The antidiabetic drug metformin exhibits antiproliferative and pro-apoptotic effects in various cells, suggesting its potential to treat a variety of malignant and non-malignant hyperplastic diseases. Clinical studies indicate that psoriasis patients with metformin treatment have a better response than those without metformin.

OBJECTIVE

The present study evaluates the antiproliferative activity and anti-inflammatory responses of metformin in human keratinocytes in vitro and explores the underlying mechanisms.

MATERIALS AND METHODS

HaCaT cells were incubated with metformin at 0, 25, 50, and 100 mM for 48 h. Antiproliferative activity was evaluated by MTT and apoptotic response was examined by flow cytometry. ELISA was used to detect IL-6, TNF-α, and VEGF protein expression. Western blot was used to investigate the expression of the mammalian target of rapamycin (mTOR) and its downstream effectors p70 ribosomal S6 kinase (p70S6K).

RESULTS

The survival rates of HaCaT cells treated with metformin at 50 mM were reduced to 75.6, 59.4, and 30.3% at 24, 48, and 72 h, respectively. The number of apoptotic HaCaT cells was significantly increased at 50 mM metformin after 48 h treatment. Metformin can exert an anti-inflammatory effect by direct inhibition of IL-6, TNF-α, and VEGF. Metformin at 50 mM significantly reduced the phosphorylation of mTOR and p70S6K, by 49.0 and 62.1%, respectively.

DISCUSSION AND CONCLUSION

Metformin treatment significantly inhibited proliferation and proinflammatory responses in HaCaT cells by a mechanism associated with inhibition of the mTOR signaling pathway. The results indicate that metformin may be used as a potential therapeutic agent for psoriasis.

Elucidation of the mTOR Pathway and Therapeutic Applications in Dermatology

The member of the phosphatidylinositol 3-kinase family, mammalian target of rapamycin, is involved in modulating inflammatory response and regulating cellular processes associated with growth, differentiation, and angiogenesis. Recent years have seen major advances in our understanding of the mammalian target of rapamycin signaling pathway and the implication of this pathway in multiple genetic and inflammatory diseases and tumors. The development of the mammalian target of rapamycin inhibitors has given rise to new treatment approaches that have led to substantially improved outcomes in many diseases. In this article, we review the role of the mammalian target of rapamycin signaling pathway in the different skin diseases with which it has been associated, examine the therapeutic applications of drugs targeting this pathway, and provide an overview of current trends and future directions in research.

Pilot Study to Evaluate the Efficacy and Safety of Oral Tacrolimus in Adult Patients With Refractory Severe Plaque Psoriasis

Background:

Tacrolimus, a congener of cyclosporine, has replaced cyclosporine as a first-line treatment for most transplant patients due to its superior efficacy and safety. Tacrolimus has not been extensively studied for the treatment of psoriasis.

Objectives:

To study the efficacy and safety of oral tacrolimus in adult patients with severe refractory plaque psoriasis.

Methods:

This was an open-label pilot study. Patients with severe plaque type psoriasis who were unresponsive to at least 1 systemic treatment were treated with oral tacrolimus.

Results:

Thirty patients were treated. After 12 weeks, improvement in mean Psoriasis Area Severity Index (PASI) score was 80.37% ( P < .001), PASI 75 was observed in 19 of 26 (73.1%) patients, and PASI 90 was observed in 11 of 26 (42.3%) patients. No severe side effects were noted.

Conclusion:

Oral tacrolimus is an effective and safe option for the short-term treatment of severe plaque psoriasis.

Proteogenomic analysis of psoriasis reveals discordant and concordant changes in mRNA and protein abundance

BACKGROUND

Psoriasis is a chronic disease characterized by the development of scaly red skin lesions and possible co-morbid conditions. The psoriasis lesional skin transcriptome has been extensively investigated, but mRNA levels do not necessarily reflect protein abundance. The purpose of this study was therefore to compare differential expression patterns of mRNA and protein in psoriasis lesions.

METHODS

Lesional (PP) and uninvolved (PN) skin samples from 14 patients were analyzed using high-throughput complementary DNA sequencing (RNA-seq) and liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

We identified 4122 differentially expressed genes (DEGs) along with 748 differentially expressed proteins (DEPs). Global shifts in mRNA were modestly correlated with changes in protein abundance (r = 0.40). We identified similar numbers of increased and decreased DEGs, but 4-fold more increased than decreased DEPs. Ribosomal subunit and translation proteins were elevated within lesions, without a corresponding shift in mRNA expression (RPL3, RPS8, RPL11). We identified 209 differentially expressed genes/proteins (DEGPs) with corresponding trends at the transcriptome and proteome levels. Most DEGPs were similarly altered in at least one other skin disease. Psoriasis-specific and non-specific DEGPs had distinct cytokine-response patterns, with only the former showing disproportionate induction by IL-17A in cultured keratinocytes.

CONCLUSIONS

Our findings reveal global imbalance between the number of increased and decreased proteins in psoriasis lesions, consistent with heightened translation. This effect could not have been discerned from mRNA profiling data alone. High-confidence DEGPs were identified through transcriptome-proteome integration. By distinguishing between psoriasis-specific and non-specific DEGPs, our analysis uncovered new functional insights that would otherwise have been overlooked.