Ida Perrotta

Human male gamete endocrinology: 1alpha, 25-dihydroxyvitamin D3 (1,25(OH)2D3) regulates different aspects of human sperm biology and metabolism

BackgroundA wider biological role of 1alpha,25-Dihydroxyvitamin D3 (1,25(OH)2D3), the active metabolite of vitamin D3, in tissues not primarily related to mineral metabolism was suggested. Recently, we evidenced the ultrastructural localization the 1,25(OH)2D3 receptor in the human sperm. However, the 1,25(OH)2D3 action in human male reproduction has not yet been clarified.Methods and ResultsBy RT-PCR, Western blot and Immunofluorescence techniques, we demonstrated that human sperm expresses the 1,25(OH)2D3 receptor (VDR). Besides, 25(OH)D3-1 alpha-hydroxylase, evidenced by Western blot analysis, indicated that in sperm 1,25(OH)2D3 is locally produced, highlighting the potential for autocrine-paracrine responses. 1,25(OH)2D3 through VDR, increased intracellular Ca2+ levels, motility and acrosin activity revealing an unexpected significance of this hormone in the acquisition of fertilizing ability. In sperm, 1,25(OH)2D3 through VDR, reduces triglycerides content concomitantly to the increase of lipase activity. Rapid responses stimulated by 1,25(OH)2D3 have been observed on Akt, MAPK and GSK3 implying that this secosteroid is involved in different sperm signalling pathways.ConclusionOur data extended the role of 1,25(OH)2D3 beyond its conventional physiological actions, paving the way for novel therapeutic opportunities in the treatment of the male reproduction disorders.

PEG-templated mesoporous silica nanoparticles exclusively target cancer cells

Mesoporous silica nanoparticles (MSNs) have been proposed as DNA and drug delivery carriers, as well as efficient tools for fluorescent cell tracking. The major limitation is that MSNs enter cells regardless of a target-specific functionalization. Here we show that non functionalized MSNs, synthesized using a PEG surfactant-based interfacial synthesis procedure, do not enter cells, while a highly specific, receptor mediated, cellular internalization of folic acid (FOL) grafted MSNs (MSN-FOL), occurs exclusively in folate receptor (FR) expressing cells. Neither the classical clathrin pathway nor macropinocytosis is involved in the MSN endocytic process, while fluorescent MSNs (MSN-FITC) enter cells through aspecific, caveolae-mediated, endocytosis. Moreover, internalized particles seem to be mostly exocytosed from cells within 96 h. Finally, cisplatin (Cp) loaded MSN-FOL were tested on cancerous FR-positive (HeLa) or normal FR-negative (HEK293) cells. A strong growth arrest was observed only in HeLa cells treated with MSN-FOL-Cp. The results presented here show that our mesoporous nanoparticles do not enter cells unless opportunely functionalized, suggesting that they could represent a promising vehicle for drug targeting applications.

Human sperm anatomy: ultrastructural localization of 1α,25-dihydroxyvitamin D3 receptor and its possible role in the human male gamete

Previous studies have suggested that 1α,25‐dihydroxyvitamin D3[1,25(OH)2D3] has a role in reproductive function. Gonadal insufficiencies were observed as a result of 1,25(OH)2D3 deficiency and in 1,25(OH)2D3 receptor (VDR) null mutant mice. To study human sperm anatomy at the molecular level, we first evaluated the ultrastructural localization of VDR by immunogold electron microscopy using a monoclonal antibody against amino acids 344–424 of human VDR, in normozoospermic samples. Intriguingly, VDR was associated predominantly with the cell nucleus. In fact, it is known that VDR is a transcription factor, and that in vitamin‐D‐depleted animals, VDR is largely localized in the cell nucleus. To assess the significance of VDR in the male gamete, we investigated the role of 1,25(OH)2D3/VDR in sperm survival and capacitation. Our results revealed that the action of 1,25(OH)2D3 depended on its concentration because although lower doses induced cholesterol efflux, protein phosphorylation and sperm survival, a higher concentration seemed to be ineffective or did not show an increased effect. These results increase our knowledge of human sperm anatomy at the molecular level and suggest that 1,25(OH)2D3/VDR may have an important role in sperm survival and the acquisition of fertilizing ability.

Estrogen receptor beta (ERβ) produces autophagy and necroptosis in human seminoma cell line through the binding of the Sp1 on the phosphatase and tensin homolog deleted from chromosome 10 (PTEN) promoter gene.

Testicular germ cell tumors are the most common tumor in male and the least studied. We focused on human seminoma using the TCAM2 cell line. Through ERβ, 10 nM estradiol (E2) was able to induce PTEN gene expression and promoter transactivation. Transient transfections, ChIP and EMSA assays evidenced the 5′-flanking region of PTEN gene promoter E2-responsive. The ERβ binding to the Sp1 on PTEN promoter decreased cell survival. The presence of ERβ or PTEN is necessary to induce the loss of cell survival upon E2, addressing their cooperation in this action. pAKT and AKT expression decreased under E2 and DPN, while known apoptotic markers appeared to be unchanged. The PI3K/AKT pathway inhibition also leads to autophagy: E2 and DPN enhanced the expression of autophagy-related markers such as PI3III, Beclin 1, AMBRA and UVRAG. MDC and TEM assays confirmed E2-induced autophagy. The absence of DNA fragmentation, caspase 9 and PARP1 cleavages suggested that necroptosis and/or parthanatos may occur. FACS analysis, LDH assay and RIP1 expression attested this hypothesis. Our study reveals a unique mechanism through which ERβ/PTEN signaling induces cell death in TCAM2 by autophagy and necroptosis. These data, supporting estrogen-dependency of human seminoma, propose ERβ ligands for therapeutic use in the treatment of this pathological condition.

The Role of Oxidative Stress and Autophagy in Atherosclerosis

Atherosclerosis is a multifactorial, multistep disorder of large- and medium-sized arteries involving, in addition to age, gender and menopausal status, a complex interplay between lifestyle and genetic risk factors. Atherosclerosis usually begins with the diffusion and retention of atherogenic lipoproteins into the subendothelial space of the artery wall where they become oxidized by local enzymes and accumulate, leading to the formation of a cushion called atheroma or atheromatous or fibrofatty plaque, composed of a mixture of macrophages, lymphocytes, smooth muscle cells (SMCs), cholesterol cleft, necrotic debris, and lipid-laden foam cells. The pathogenesis of atherosclerosis still remains incompletely understood but emerging evidence suggests that it may involve multiple cellular events, including endothelial cell (EC) dysfunction, inflammation, proliferation of vascular SMCs, matrix (ECM) alteration, and neovascularization. Actually, a growing body of evidence indicates that autophagy along with the chronic and acute overproduction of reactive oxygen species (ROS) is integral to the development and progression of the disease and may represent fruitful avenues for biological investigation and for the identification of new therapeutic targets. In this review, we give an overview of ROS and autophagy in atherosclerosis as background to understand their potential role in this vascular disease.

New evidence for a critical role of elastin in calcification of native heart valves: immunohistochemical and ultrastructural study with literature review.

Perrotta I, Russo E, Camastra C, Filice G, Di Mizio G, Colosimo F, Ricci P, Tripepi S, Amorosi A, Triumbari F & Donato G
(2011) Histopathology59, 504–513

The nuclear localization signal is required for nuclear GPER translocation and function in breast Cancer-Associated Fibroblasts (CAFs).

Cancer associated fibroblasts (CAFs) actively contribute to the growth and invasion of cancer cells. In recent years, the G protein estrogen receptor (GPER) has been largely involved in the estrogenic signals in diverse types of normal and tumor cells. In CAFs, GPER was localized into the nucleus, however the molecular mechanisms which regulate its nuclear shuttle remain to be clarified. In the present study, we demonstrate that in breast CAFs GPER translocates into the nucleus through an importin-dependent mechanism. Moreover, we show that a nuclear localization signal is involved in the nuclear import of GPER, in the up-regulation of its target genes c-fos and CTGF and in the migration of CAFs induced by estrogens. Our data provide novel insights into the nuclear localization and function of GPER in CAFs toward a better understanding of the estrogen action elicited through these key players of the tumor microenvironment.

Human sperm physiology: Estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) influence sperm metabolism and may be involved in the pathophysiology of varicocele-associated male infertility†

The mechanisms by which varicocele affects fertility remain undetermined. Estrogens play a key role in the human male reproduction and human sperm expresses the estrogen receptors (ERs) and aromatase. In this study, by Western blotting we evidenced the ERs content concomitantly in healthy sperm and in oligoastenoteratozoospermic (OAT) samples without and with varicocele. In varicocele a strong reduction of the ERβ was observed, while the ERα was almost absent. Besides, transmission electron microscopy (TEM) confirmed the reduction of ERs expression in “varicocele” sperm, indicating that varicocele has a detrimental effect on sperm structure at molecular level. To further define the estrogen significance in male gamete and the pathophysiology of varicocele we investigated both the expression of ERα and ERβ in normal and pathologic sperm samples as well as we evaluated estradiol (E2) action on lipid and glucose sperm metabolism. Responses to E2 treatments on cholesterol efflux, protein tyrosine phosphorylations, motility, and acrosin activity in varicocele sperm were reduced or absent. The evaluation of the triglycerides content, lipase and acyl‐CoA dehydrogenase activities, suggest that E2 exerts a lipolytic effect on human sperm metabolism. Concerning glucose metabolism, it appears that E2 induces G6PDH activity concomitantly to the insulin secretion. In “varicocele” sperm, the E2 did not induce energy expenditure. OAT sperm had E2‐responsiveness but in a lesser extent with respect healthy sperm. This study discovered a novel role for E2/ERs in human sperm physiology, since they modulate sperm metabolism and new detrimental effects related to the pathophysiology of the varicocele condition. J. Cell. Physiol. 226: 3403–3412, 2011.

Pathological findings in subsynovial connective tissue in idiopathic carpal tunnel syndrome.

Recent studies suggest that in patients with carpal tunnel syndrome, pathological changes occur in the subsynovial connective tissue. Such changes are non-inflammatory synovial fibrosis and vascular proliferation. Thickening of the tendon sheet may cause an increase of canal pressure and damages to the median nerve in the wrist; however, the causes of such events still remain to be clarified. We examined synovial specimens from 26 patients operated on for idiopathic carpal tunnel syndrome. Analysis included histological, ultrastructural and immunohistochemical examination in order to establish a pathological underlying pattern. An explanation for the pathogenesis of the found changes suggested. Our data confirm the presence of a non-inflammatory fibrosis with irregular bundles of collagen. De novo blood vessel formation was also noted. Interestingly the neo-angiogenesis consists of anomalous vessels and may be triggered from various cell types secreting vascular endothelial growth factor (VEGF), including macrophage-like elements similar to endothelial progenitor cells. Therefore, we believe that in the future a non-surgical management of carpal tunnel syndrome might be conjecturable via anti-VEGF drugs.

Human Sperm Anatomy: Ultrastructural Localization of the Cannabinoid1 Receptor and a Potential Role of Anandamide in Sperm Survival and Acrosome Reaction

Recently, the endocannabinoid (EC) system and the presence of CB1 receptor (CB1‐R), have been identified in human sperm. However, the effects of EC receptor ligands such as anandamide (N‐arachidonoylethanolamine) and the role of EC system in male fertility is still largely unexplored. In the present study, we investigated the ultrastructural compartmentalization of CB1‐R and analyzed the effects of its stimulation by using a stable analog of anandamide, 2‐methylarachidonyl‐2′‐fluoro‐ethylamide (MET‐F‐AEA). We focused particularly on sperm survival and acrosin activity. The study of human sperm anatomy by transmission electron microscopy with immunogold analysis revealed the location of the CB1‐R prevalently in the sperm membranes of the head and interestingly on the mitochondria. The effect of different concentrations of MET‐F‐AEA from 100 nM to 1 μM evidenced a significant decrease of sperm survival. Interestingly, we analyzed this negative effect at molecular level, testing the EC action on different known sperm survival targets. MET‐F‐AEA‐treatment decreased both pBCL2 and pAkt, two prosurvival proteins, and increased pPTEN expression which is the main regulator of the PI3K/Akt pathway. Moreover, a biphasic effect was observed with increasing MET‐F‐AEA concentrations on the acrosin activity. The blockage of the CB1‐R by using its selective antagonist SR141716 (rimonabant) induced an opposite action on sperm survival supporting a role for this receptor in the biology of the male gamete. Anat Rec, 2010.