Rapamycin promotes autophagy cell death of Kaposi's sarcoma cells through P75NTR activation.

The mammalian target of rapamycin inhibitor (mTOR-I) Rapamycin, a drug widely used in kidney transplantation, exerts important anti-cancer effects, particularly in Kaposi's Sarcoma (KS), through several biological interactions. In this in vivo and in vitro study, we explored whether the activation of the autophagic pathway through the low-affinity receptor for nerve growth factor, p75NTR , may have a pivotal role in the anti-cancer effect exerted by Rapamycin in S. Our Kimmunohistochemistry results revealed a significant hyper-activation of the autophagic pathway in KS lesions. In vitro experiments on KS cell lines showed that Rapamycin exposure reduced cell viability by increasing the autophagic process, in the absence of apoptosis, through the transcriptional activation of p75NTR via EGR1. Interestingly, p75NTR gene silencing prevented the increase of the autophagic process and the reduction of cell viability. Moreover, p75NTR activation promoted the upregulation of phosphatase and tensin homolog (PTEN), a tumour suppressor that modulates the PI3K/Akt/mTOR pathway. In conclusion, our in vitro data demonstrated, for the first time, that in Kaposi's sarcoma, autophagy triggered by Rapamycin through p75NTR represented a major mechanism by which mTOR inhibitors may induce tumour regression. Additionally, it suggested that p75NTR protein analysis could be proposed as a new potential biomarker to predict response to Rapamycin in kidney transplant recipients affected by Kaposi's sarcoma.

Proinflammatory profile of visceral adipose tissue and oxidative stress in severe obese patients carrying the variant rs4612666 C of NLRP3 gene.

BACKGROUND: The activation of NLRP3 inflammasome machinery has a central role in obesity-induced inflammation. Genetic studies well support the involvement of functional variants of NLRP3 and its negative regulator, CARD8, in the pathogenesis of complex diseases with an inflammatory background. We have investigated the influence of NLRP3 (rs4612666; rs10754558) and CARD8 (rs204321) genetic variants in both the inflammatory status of visceral adipose tissue (VAT) from patients with severe obesity and in the systemic oxidative stress before and after sleeve-gastrectomy (SLG). METHODS: Twenty-three consecutive severe obese patients candidate to SLG were enrolled in the study. Visceral adipose tissue (VAT) biopsies, obtained during SLG, were used to evaluate the expression of NLRP3, IL-1ß, IL-6, and MCP-1 by real-time RT-PCR. DNA was extracted from peripheral blood lymphocytes and genotyped by RFLP analysis. Before and 3 months after SLG, all patients underwent the assessment of oxidative stress, biochemical parameters, and body composition as measured by bioelectrical impedance analysis (BIA). RESULTS: Increased expression of NLRP3, IL-6, IL-1ß, and MCP-1 mRNA was observed in VAT of rs4612666 C variant carriers, in which higher oxidative stress was also detected as compared to non-carrier individuals. In all patients, oxidative stress, biochemical and BIA parameters improved after SLG, regardless of genotype. No significant correlations were found with the other genetic variants. CONCLUSIONS: Our results suggest that the NLRP3 rs4612666 C variant may promote a worse pro-inflammatory milieu and higher oxidative stress, thus leading patients to a more severe obesity phenotype. A larger study is needed to confirm this assumption and to investigate the impact of the NLRP3 rs4612666 C variant on severe obesity.

An Olive Leaf Extract Rich in Polyphenols Promotes Apoptosis in Cervical Cancer Cells by Upregulating p21Cip/WAF1 Gene Expression.

Most of the common drugs used to treat the cervical cancer, which main etiological factor is the HPV infection, cause side effects and intrinsic/acquired resistance to chemotherapy. In this study we investigated whether an olive leaf extract (OLE), rich in polyphenols, was able to exert anti-tumor effects in human cervical cancer cells (HeLa). MTT assay results showed a reduction of HeLa cells viability OLE-induced, concomitantly with a gene and protein down-regulation of Cyclin-D1 and an up-regulation of p21, triggering intrinsic apoptosis. OLE reduced NFkB nuclear translocation, which constitutive activation, stimulated by HPV-oncoproteins, promotes cancer progression and functional studies revealed that OLE activated p21Cip/WAF1 in a transcriptional-dependent-manner, by reducing the nuclear recruitment of NFkB on its responsive elements. Furthermore, OLE treatment counteracted epithelial-to-mesenchymal-transition and inhibited anchorage-dependent and -independent cell growth EGF-induced. Finally, MTT assay results revealed that OLE plus Cisplatin strengthened the reduction of cells viability Cisplatin-induced, as OLE inhibited NFkB, AkT and MAPK pathways, all involved in Cisplatin chemoresistance. In conclusion, we demonstrated that in HeLa cells OLE exerts pro-apoptotic effects, elucidating the molecular mechanism and that OLE could mitigate Cisplatin chemoresistance. Further studies are needed to explore the potential coadiuvant use of OLE for cervical cancer treatment.

NFKB1 promoter polymorphism: A new predictive marker of cytomegalovirus infection after kidney transplantation.

INTRODUCTION: Cytomegalovirus (CMV) infection represents a common cause of morbidity and mortality in kidney transplant recipients (KTR). The NF-kB signaling pathway is highly involved in the pathogenesis of CMV infection. The -94ins/delATTG functional polymorphism in the promoter of NFKB1 has been associated with low intracellular levels of the protein and high incidence of inflammatory and autoimmune disease. In this study, we evaluated the association of this NFKB1 polymorphism with the risk of CMV infection. METHODS: CMV infection was defined as virus isolation or detection of viral antigens or nucleic acid in any body fluid or tissue specimen. Using Cox regression and survival analysis, we analyzed the association between the polymorphism and CMV infection as well as recurrence in the first 12 months after transplantation. RESULTS: We analyzed the -94ins/delATTG NFKB1 polymorphism of 189 KTRs. The 65% of CMV infections occurred in ins/ins group. Survival free from CMV infection was 54.7% for ins/ins group and 79.4% for deletion carriers one year after transplantation (P < 0.0001). At multivariate regression, deletion carriers showed a lower risk of CMV infection and recurrence with respect to ins/ins KTRs (HR = 0.224 P = 0.0002; HR = 0.307, P = 0.012, respectively). CONCLUSIONS: In conclusion, pretransplantation screening for NFKB1 -94ins/delATTG polymorphism may predict CMV infection and improve the management of patients at higher risk of infection in the post-transplant period.

Testosterone in renal transplant patients: effect on body composition and clinical parameters.

BACKGROUND: Clinical studies have demonstrated that, after renal transplantation (TX), testosterone deficiency (TD) at the time of the procedure is independently associated with lower survival of the patient and graft. However, data between TD and the functional CAG polymorphism of the androgen receptor promoter (AR) are discordant. We investigated the prevalence of TD and its association with body composition, biochemical parameters, the Aging Males' Symptoms rating scale (AMS) domains and AR polymorphism. METHODS: In 112 TX patients, we assessed the AMS, biochemical/hormonal (FSH/LH/TT) anthropometric/bioimpedance analysis parameters, and AR CAG polymorphism of AR by gene sequencing. RESULTS: Median values of total testosterone (TT) were 340 ng/dl and 52% of TX patients were affected by TD. Significant correlations between TT and FSH and FSH and LH (p = 0.005, p < 0.0001, respectively) were found. TD patients had lower estimated glomerular filtration rate (eGFR) and hemoglobin (Hb) (p = 0.034, p = 0.022 respectively) and showed higher values of C-reactive protein (p = 0.023) and fat tissue index/adipose tissue mass (p = 0.034 and p = 0.021, respectively), and lower values of serum albumin (p = 0.003) and high-density lipoprotein-cholesterol (p = 0.038) levels. Significant differences were found in the number of patients on mammalian target of rapamycin inhibitors immunosuppressant therapy (p = 0.045). Logistic regression analysis did not show any correlation between age, AMS scores, TT or CAG repeat length, gonadotropins, time of the transplant, and dialysis. CONCLUSIONS: Our results suggest that in TX recipients an appropriate sexual hormonal evaluation should be performed, as we found a high prevalence of TD. However, further studies are needed to clarify the association between TD and patient and graft survival.

Early subclinical rejection treated with low dose i.v. steroids is not associated to graft survival impairment: 13-years' experience at a single center.

Subclinical rejection (SCR) has been variably associated with reduced graft survival, development and progression of interstitial fibrosis/tubular atrophy and chronic allograft nephropathy, but data are controversial concerning SCR treatment in terms of graft survival improvement. In this single-center retrospective study, we enrolled 174 adult kidney transplant recipients with a protocol biopsy performed at 30 days after transplantation to evaluate the incidence rate and risk factors for early SCR and its impact on 10-year graft survival. Five patients showed primary non function and were excluded. Among 159/169 (94.08 %) patients with stable graft function who underwent protocol biopsy, 17 (10.7 %) showed signs of SCR and were treated with low-dose intravenous (i.v.) steroids. Ten patients showed functional impairment, 8 (4.73 %) resulting as acute rejection. At multivariate analysis, donor age [odds ratio (OR) 1.04, 95 % confidence interval (CI) 1.01-1.09], and delayed graft function (DGF) (OR 1.08, 95 % CI 1.03-1.12) were significantly associated with SCR. The 10-year graft survival rate in the SCR group was similar to that in the normal-findings group (76.5 vs. 74.9 % respectively; p = 0.61). At multivariate Cox regression, acute [hazard ratio (HR) 5.22, 95 % CI 1.70-16.01], but not sub-clinical, rejection was independently associated with long-term graft failure. In conclusion, early protocol biopsy is a useful and safe tool to detect early SCR which seems not to affect the long-term survival. We suggest that this could be, probably, linked to early SCR treatment with low dose i.v. steroids.

Adiponectin secreted by tubular renal cells during LPS exposure worsens the cellular inflammatory damage.

The pathogenetic role of adiponectin (ADPN) in kidney failure is not yet elucidated, since in vitro and in vivo studies have demonstrated that ADPN exerts both anti-inflammatory and pro-inflammatory effects. Starting from our previous findings demonstrating that HK-2 cells express and secrete ADPN, in this study we investigated the autocrine role of ADPN in tubular inflammatory damage induced by lipopolysaccharide (LPS) and the underlying molecular mechanisms. Firstly, we observed that short-term exposure to LPS enhanced ADPN protein expression as well as the adiponectin receptor ADIPOR1 mRNA content together with its signaling pathway downstream, pAMPK/pERK/pJNK, whose up-regulation status was reversed when ADPN gene knockdown occurred. Interestingly, in the same experimental conditions, we observed that ADPN mediated the nuclear translocation of the transcription factors nuclear factor kappa B (NFkB) and pcFos/pcJun (activator protein 1, AP-1), both induced by the pJNK pathway and involved in tumor necrosis factor (TNF)-α transactivation. Indeed, by transient transfection assay, we observed that the LPS-induced increase of TNF-α promoter activity was abrogated in cells pretreated with the inhibitors of NFkB and AP-1. Collectively our results suggest that in HK-2 cells, ADPN produced upon LPS stimulus could worsen the inflammatory damage in an autocrine-dependent manner.

Nerve growth factor exposure promotes tubular epithelial-mesenchymal transition via TGF-ß1 signaling activation.

Clinical studies showed that renal expression and serum levels of nerve growth factor (NGF) are increased in renal diseases characterized by progressive fibrosis, a pathologic process in which TGF-ß1 mediates most of the key events leading to tubular epithelial-mesenchymal transition (EMT). However, the pathogenic role of high NGF levels has not yet been elucidated. In this study, we found that in tubular renal cells, HK-2, NGF transcriptionally up-regulated TGF-ß1 expression and secretion and enhanced cell motility by activating EMT markers via its receptors, TrkA and p75(NTR). Interestingly, we observed that TGF-ß1-SMAD pathway activation and the up-regulation of EMT markers NGF-induced were both prevented when knockdown of TGF-ß1 gene occurred and that the pretreatment with an antibody anti-NGF reversed the nuclear translocation of pSMAD3/SMAD4 complex. Collectively, our results demonstrated that NGF promotes renal fibrosis via TGF-ß1-signaling activation, suggesting that in kidney diseases high NGF serum levels could contribute to worsen renal fibrosis.

Soluble Klotho levels in adult renal transplant recipients are modulated by recombinant human erythropoietin.

BACKGROUND: Data on serum soluble Klotho levels in chronic kidney disease are contradictory and even less is known after renal transplantation. Experimental studies demonstrated that recombinant human erythropoietin (rhEPO) treatment mitigates Klotho reduction caused by renal damage. Therefore, this study aimed to determine serum Klotho levels in a cohort of kidney transplant recipients (KTR) and to evaluate whether rhEPO treatment can modulate, in vivo and in vitro, soluble Klotho. METHODS: 117 KTR and 22 healthy subjects (HS) were enrolled. In 17 KTR, rhEPO was discontinued for 5 weeks and Klotho levels were compared to 34 propensity score-matched controls. Moreover, we evaluated Klotho mRNA expression and protein secretion in HK-2 tubular cells treated with cyclosporin A (CyA) and rhEPO, alone or in combination. RESULTS: Serum Klotho levels in KTR were significantly higher than in HS (0.68 vs. 0.37, p = 0.002) and significantly associated with estimated glomerular filtration rate (r = -0.378, p = 0.003) and fibroblast growth factor 23 (r = -0.307, p < 0.0001). After 5 weeks of rhEPO discontinuation, treated KTR showed a sharper reduction of Klotho levels than controls (-0.56 vs. -0.11 ng/ml, p < 0.0001). In HK-2 cells CyA treatment induced a Klotho down-regulation that was mitigated by rhEPO pre-treatment. In the same experimental conditions, our results revealed that cells treated with CyA + rhEPO secreted higher soluble Klotho levels than those exposed to CyA or rhEPO alone. CONCLUSIONS: Our results demonstrate that KTR have higher serum Klotho levels than HS and that rhEPO treatment modulates these concentrations, suggesting a link between rhEPO and soluble Klotho in KTR.

Exposure to nerve growth factor worsens nephrotoxic effect induced by Cyclosporine A in HK-2 cells.

Nerve growth factor is a neurotrophin that promotes cell growth, differentiation, survival and death through two different receptors: TrkA(NTR) and p75(NTR). Nerve growth factor serum concentrations increase during many inflammatory and autoimmune diseases, glomerulonephritis, chronic kidney disease, end-stage renal disease and, particularly, in renal transplant. Considering that nerve growth factor exerts beneficial effects in the treatment of major central and peripheral neurodegenerative diseases, skin and corneal ulcers, we asked whether nerve growth factor could also exert a role in Cyclosporine A-induced graft nephrotoxicity. Our hypothesis was raised from basic evidence indicating that Cyclosporine A-inhibition of calcineurin-NFAT pathway increases nerve growth factor expression levels. Therefore, we investigated the involvement of nerve growth factor and its receptors in the damage exerted by Cyclosporine A in tubular renal cells, HK-2. Our results showed that in HK-2 cells combined treatment with Cyclosporine A + nerve growth factor induced a significant reduction in cell vitality concomitant with a down-regulation of Cyclin D1 and up-regulation of p21 levels respect to cells treated with Cyclosporine A alone. Moreover functional experiments showed that the co-treatment significantly up-regulated human p21promoter activity by involvement of the Sp1 transcription factor, whose nuclear content was negatively regulated by activated NFATc1. In addition we observed that the combined exposure to Cyclosporine A + nerve growth factor promoted an up-regulation of p75 (NTR) and its target genes, p53 and BAD leading to the activation of intrinsic apoptosis. Finally, the chemical inhibition of p75(NTR) down-regulated the intrinsic apoptotic signal. We describe two new mechanisms by which nerve growth factor promotes growth arrest and apoptosis in tubular renal cells exposed to Cyclosporine A.