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.

Outcomes of pregnancies in patients with Gaucher Disease: The experience of a center of excellence on rare metabolic Disease-Gaucher Disease, in Greece.

OBJECTIVE: Pregnancy is reported to exacerbate manifestations in women with Gaucher Disease (GD). The objective of our study was to examine the outcome of pregnancies of Caucasian women with GD in a Greek Center of Excellence on GD. STUDY DESIGN: Fifteen GD women were enrolled. All data were collected by questionnaire: fertility, normal pregnancies, spontaneous-elective-therapeutic abortions, maternal -neonatal status, birth weight and chromosomal abnormalities. RESULTS: Forty-one pregnancies were reported among 15 women: mean conception age (±SD) 27.7 ±â€¯5.8years (range 17-42years). Thirty-seven conceptions were spontaneous, 4 were after in vitro fertilization (IVF). Twenty three out of the 41 (56.1 %) pregnancies were normal. Eleven out of the 41 (26.8 %) pregnancies resulted in spontaneous abortions, 3 out of 41 (7.3 %) in elective and 3 out of 41 (7.3 %) in therapeutic abortions. Therapeutic abortions were due to worsening of GD manifestations, fetal chromosomal abnormalities and GD type 2 embryo. Nine out of 15 women had maternal complications: gestational diabetes, splenomegaly, hepatomegaly, thrombocytopenia, osteoporosis and postpartum hemorrhage. Twenty three out of the 41 pregnancies resulted in live births. Nine out of the 23 (39.1 %) deliveries were caesarian sections and 14 out of 23 (60.9 %) were vaginal. The total number of neonates was 24 (14 females / 10 males). Mean gestational age on delivery (± SD) was 35.9 ±â€¯3.1 weeks (range 26-38 w). Average female birth weight (±SD) was 2671.4 ±â€¯851.6 g (range 900-4100 grams) and male was 3333 ±â€¯996.4 g (range 1930-4700 grams). Nine out of 24 (37.5 %) neonates had low birth weight. Average low birth weight (±SD) was 1931.1 ±â€¯420.52 g (range 900-2300 grams). Twenty out of the 24 (83.3 %) neonates were healthy. Four out of 24 neonates had neonatal complications: two neonates had GD type 1, one had GD type 3 and one neonate died two days after delivery (it was born at 26 weeks). Four neonates were hospitalized in incubators at the intensive neonatal care unit due to low birth weight. Thirty-nine women did not receive enzyme replacement therapy for GD during pregnancy, while, in two pregnancies, treatment was discontinued during the first trimester and re-administered after that. Mean first menarche age (±SD) was 13.6 ±â€¯0.7 years. Thirteen out of 15 women were menopausal, mean menopausal age (± SD) 466 ±â€¯2.6 years. CONCLUSION: Most of GD women experience uncomplicated pregnancies and deliver normal, healthy infants, although the rate of complications and the rate of abortions is high in this population.

Polycystin-1 induces activation of the PI3K/AKT/mTOR pathway and promotes angiogenesis in renal cell carcinoma.

In the present study we investigated the expression and the functional role of mechanosensitive polycystins in renal cell carcinoma (RCC). In 115 RCC patients we evaluated the protein expression of polycystin-1 (PC1), polycystin-2 (PC2), VEGF and protein components of the PI3K/Akt/mTOR pathway, which have been implicated both in RCC and polycystic kidney disease. PC1 and PC2 demonstrated reduced expression throughout the RCC tissue compared to the adjacent normal tissue. PC1 and PC2 revealed high expression when they were associated with higher grade and decreased 5-year survival respectively. PC1 and PC2 were positively correlated with p110γ subunit of PI3K and high PC1 expressing cells tended to display activation/phosphorylation of Akt. There was also a positive association between PC1 and VEGF expression, whereas PC1 augmented the tumor's microvascular network in stage IV carcinomas. In human RCC cells, functional inhibition of PC1 resulted in upregulation of the PI3K/Akt/mTOR pathway, enhanced cell proliferation and led to inhibition of cell migration. Conclusively, aberrant PC1 regulation is associated with increased angiogenesis and features of advanced disease in RCC tissues.

Molecular mechanisms of mechanotransduction in psoriasis.

Psoriasis is an immune disease of the skin that frequently develops upon triggering events of mechanical nature and leads to increased proliferation and damaged differentiation of keratinocytes of the epidermis. Mechanical forces are mediated through mechanotransduction, which is the process that translates physical cues into biochemical signaling networks. Latest updates underline the role of mechanotransduction during the acquisition of aberrant properties by the keratinocytes of the skin, therefore implying a potential contribution that promotes psoriasis pathogenesis. The present review discusses the mechano-induced signaling pathways and individual molecules that become activated in psoriasis and in keratinocytes, along with mechano-based putative treatment strategies. We also suggest emerging mechanosensitive molecules for further investigation with potential diagnostic and therapeutic utility in psoriasis.

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.