Quantitative next-generation sequencing-based analysis indicates progressive accumulation of microsatellite instability between atypical hyperplasia/endometrial intraepithelial neoplasia and paired endometrioid endometrial carcinoma.

Atypical hyperplasia/endometrial intraepithelial neoplasia is an accepted precursor to endometrioid-type endometrial carcinoma. Mismatch repair-deficient endometrial carcinomas are also known to be a biologically and clinically distinct subset of tumors. However, the development of microsatellite instability in endometrial carcinogenesis has not yet been evaluated by novel next-generation sequencing-based methods. We examined 17 mismatch repair-deficient endometrioid endometrial carcinomas and their paired atypical hyperplasia/endometrial intraepithelial neoplasia precursors using a next-generation sequencing panel with quantitative microsatellite instability detection at 336 loci. Findings were compared to histological features, polymerase chain reaction-based microsatellite instability testing, immunohistochemical expression of mismatch repair proteins, and tumor mutational burden calculations. All 17 endometrial carcinomas and 8/17 atypical hyperplasia/endometrial intraepithelial neoplasia showed microsatellite instability by next-generation sequencing-based testing. Endometrial carcinoma specimens showed significantly more unstable microsatellite loci than paired atypical hyperplasia/endometrial intraepithelial neoplasia (mean: 40.0% vs 19.9 unstable loci, respectively). Out of nine microsatellite-stable atypical hyperplasia/endometrial intraepithelial neoplasia specimens, four showed mismatch repair loss by immunohistochemistry. All atypical hyperplasia/endometrial intraepithelial neoplasia and endometrial carcinoma specimens with microsatellite instability were also mismatch repair-deficient by immunohistochemistry. Tumor mutational burden was significantly greater in endometrial carcinoma than in paired atypical hyperplasia/endometrial intraepithelial neoplasia specimens, and tumor mutational burden was significantly correlated with percent unstable microsatellite loci. Paired atypical hyperplasia/endometrial intraepithelial neoplasia and endometrial carcinoma specimens show progressive accumulation of unstable microsatellite loci following loss of mismatch repair protein expression. Comprehensive next-generation sequencing-based testing of endometrial carcinomas offers new insights into endometrial carcinogenesis and opportunities for improved tumor surveillance, diagnosis, and management.

Hedgehog pathway plays a vital role in HIV-induced epithelial-mesenchymal transition of podocyte.

HIV-associated nephropathy (HIVAN) is characterized by heavy proteinuria, rapidly progressive renal failure, and distinct morphological features in the kidney. HIV-induced epithelial-mesenchymal transition (EMT) is critically important for the progression of kidney injury. In this study, we tested the role of hedgehog pathway in the HIV-induced EMT and fibrosis of kidney. We used the Tg26 mice, the abundantly used HIVAN mouse model, to investigate the activation of hedgehog pathway by HIV. Western blotting and real time PCR results showed that renal tissue expression of hedgehog pathway related molecules, including hedgehog homologous (Shh, Ihh, Dhh), PTCH, and Gli1, were increased in HIVAN (Tg26) mice; while immunofluorescent staining displayed localization PTCH expression in podocytes. For in vitro studies, we used recombinant sonic hedgehog (Shh) and HIV for their expression by podocytes. Both the methods activated the hedgehog pathway, enhanced the expression of EMT markers, and decreased impermeability. Overexpression of Gli1 by human podocytes also augmented their expression of EMT markers. On the other hand, the blockade of hedgehog pathway with Gant 58, a specific blocker for Gli1-induced transcription, dramatically decreased HIV-induced podocyte EMT and permeability. These results indicate that hedgehog pathway plays an important role in HIV-induced podocyte injury. The present study provides mechanistical insight into a new target for therapeutic strategy.

Magnesium protects against cisplatin-induced acute kidney injury by regulating platinum accumulation.

Despite its success as a potent antineoplastic agent, ∼25% of patients receiving cisplatin experience acute kidney injury (AKI) and must discontinue therapy. Impaired magnesium homeostasis has been linked to cisplatin-mediated AKI, and because magnesium deficiency is widespread, we examined the effect of magnesium deficiency and replacement on cisplatin-induced AKI in physiologically relevant older female mice. Magnesium deficiency significantly increased cisplatin-associated weight loss and markers of renal damage (plasma blood urea nitrogen and creatinine), histological changes, inflammation, and renal cell apoptosis and modulated signaling pathways (e.g., ERK1/2, p53, and STAT3). Conversely, these damaging effects were reversed by magnesium. Magnesium deficiency alone significantly induced basal and cisplatin-mediated oxidative stress, whereas magnesium replacement attenuated these effects. Similar results were observed using cisplatin-treated LLC-PK1 renal epithelial cells exposed to various magnesium concentrations. Magnesium deficiency significantly amplified renal platinum accumulation, whereas magnesium replacement blocked the augmented platinum accumulation after magnesium deficiency. Increased renal platinum accumulation during magnesium deficiency was accompanied by reduced renal efflux transporter expression, which was reversed by magnesium replacement. These findings demonstrate the role of magnesium in regulating cisplatin-induced AKI by enhancing oxidative stress and thus promoting cisplatin-mediated damage. Additional in vitro experiments using ovarian, breast, and lung cancer cell lines showed that magnesium supplementation did not compromise cisplatin's chemotherapeutic efficacy. Finally, because no consistently successful therapy to prevent or treat cisplatin-mediated AKI is available for humans, these results support developing more conservative magnesium replacement guidelines for reducing cisplatin-induced AKI in cancer patients at risk for magnesium deficiency.

Bone-derived mesenchymal stromal cells from HIV transgenic mice exhibit altered proliferation, differentiation capacity and paracrine functions along with impaired therapeutic potential in kidney injury.

Mesenchymal stem cells (MSCs) secrete paracrine factors that could be cytoprotective and serve roles in immunoregulation during tissue injury. Although MSCs express HIV receptors, and co-receptors, and are susceptible to HIV infection, whether HIV-1 may affect biological properties of MSCs needs more study. We evaluated cellular proliferation, differentiation and paracrine functions of MSCs isolated from compact bones of healthy control mice and Tg26 HIV-1 transgenic mice. The ability of MSCs to protect against cisplatin toxicity was studied in cultured renal tubular cells as well as in intact mice. We successfully isolated MSCs from healthy mice and Tg26 HIV-1 transgenic mice and found the latter expressed viral Nef, Vpu, NL4-3 and Vif genes. The proliferation and differentiation of Tg26 HIV-1 MSCs was inferior to MSCs from healthy mice. Moreover, transplantation of Tg26 HIV-1 MSCs less effectively improved outcomes compared with healthy MSCs in mice with acute kidney injury. Also, Tg26 HIV-1 MSCs secreted multiple cytokines, but at significantly lower levels than healthy MSCs, which resulted in failure of conditioned medium from these MSCs to protect cultured renal tubular cells from cisplatin toxicity. Therefore, HIV-1 had adverse biological effects on MSCs extending to their proliferation, differentiation, function, and therapeutic potential. These findings will help in advancing mechanistical insight in renal injury and repair in the setting of HIV-1 infection.

Rapamycin-induced modulation of miRNA expression is associated with amelioration of HIV-associated nephropathy (HIVAN).

Recent studies suggested that miRNAs are involved in the development of the pathogenesis of HIV-associated nephropathy (HIVAN). Rapamycin, a widely used mTOR inhibitor, has been demonstrated to slow down the progression of HIVAN. However, the role of miRNA in the regulation of these processes has not been investigated so far. In the current study, we have used a microarray-based approach in combination with real-time PCR to profile the miRNA expression patterns in rapamycin-treated HIVAN mice (Tg26). Our results demonstrated that 19 miRNAs belonging to 13 different families expressed differentially in renal tissues of rapamycin-receiving Tg26 mice when compared to Tg26 mice-receiving saline only. The patterns of miRNAs expression in rapamycin-receiving Tg26 mice took a reverse turn. These miRNAs were classified into 8 functional categories. In in vitro studies, we examined the expression of specific miRNAs in HIV-1 transduced human podocytes (HIV/HPs). HIV/HPs displayed attenuation of expression of miR-99a, -100a, -199a and miR-200, whereas, rapamycin inhibited this effect of HIV. These findings suggest that rapamycin-mediated up-regulation of specific miRNAs could contribute to amelioration of renal lesions in HIVAN mice.

mTOR plays a critical role in p53-induced oxidative kidney cell injury in HIVAN.

Oxidative stress has been implicated to contribute to HIV-induced kidney cell injury; however, the role of p53, a modulator of oxidative stress, has not been evaluated in the development of HIV-associated nephropathy (HIVAN). We hypothesized that mammalian target of rapamycin (mTOR) may be critical for the induction of p53-mediated oxidative kidney cell injury in HIVAN. To test our hypothesis, we evaluated the effect of an mTOR inhibitor, rapamycin, on kidney cell p53 expression, downstream signaling, and kidney cell injury in both in vivo and in vitro studies. Inhibition of the mTOR pathway resulted in downregulation of renal tissue p53 expression, associated downstream signaling, and decreased number of sclerosed glomeruli, tubular microcysts, and apoptosed and 8-hydroxy deoxyguanosine (8-OHdG)-positive (+ve) cells in Tg26 mice. mTOR inhibition not only attenuated kidney cell expression of p66ShcA and phospho-p66ShcA but also reactivated the redox-sensitive stress response program in the form of enhanced expression of manganese superoxide dismutase (MnSOD) and catalase. In in vitro studies, the mTOR inhibitor also provided protection against HIV-induced podocyte apoptosis. Moreover, mTOR inhibition downregulated HIV-induced podocyte (HP/HIV) p53 expression. Since HP/HIV silenced for mTOR displayed a lack of expression of p53 as well as attenuated podocyte apoptosis, this suggests that mTOR is critical for kidney cell p53 activation and associated oxidative kidney cell injury in the HIV milieu.

Deficit of p66ShcA restores redox-sensitive stress response program in cisplatin-induced acute kidney injury.

Overwhelming oxidative stress and compromised tubular cell antioxidant response have been incriminated for cisplatin (Cis)-induced acute kidney injury (AKI). We hypothesized that Cis-induced AKI was the outcome of the deactivated redox-sensitive stress response program (RSSRP). Wild type (WT) and heterozygous p66ShcA(p66(+/-)) mice in groups of six were administered either normal saline (WT) or Cis (12.5 mg/kg, intraperitoneal, Cis/WT). Renal biomarkers were collected and kidneys were harvested for renal histology. Cis/WT showed elevated blood urea nitrogen levels and enhanced tubular cell apoptosis, necrosis, and dilated tubules filled with casts when compared to Cis/p66(+/-). Cis/p66(+/-) developed only a clinically occult AKI (normal blood urea levels and only microscopic alterations). Immunoblots from the lysates of renal tissues of Cis/WT displayed enhanced expression of phospho-p66ShcA, and phospho-Foxo3A but attenuated expression of MnSOD and catalase; conversely, p66 deficit prevented these alterations in Cis milieu. In in vitro studies, Cis treated mouse proximal tubular cells (MPTCs) displayed enhanced phosphorylation of p66ShcA and no increase in tubular cell expression of MnSOD. In addition, renal tissues of Cis/WT and Cis-treated MPTCs displayed enhanced phosphorylation of p53 and Bax expression. However, MPTC partially silenced for p66ShcA displayed partial inhibition of Cis-induced tubular cell apoptosis as well as necrosis. These findings indicate that Cis-induced AKI is the outcome of the deactivated RSSRP (attenuated anti-oxidant response) and activation of pro-apoptotic (p53-induced Bax expression) pathway.

MicroRNAs in HIV-associated nephropathy (HIVAN).

MicroRNAs (miRNAs) play a critical role in multiple biological and metabolic processes. Recent studies suggested that miRNAs are critical in the maintenance of glomerular homeostasis in both physiological and pathological states. However, the role of miRNAs in the pathogenesis of HIV-associated nephropathy (HIVAN) has not been studied. In the present study, we have used a microarray-based approach in combination with real-time PCR to profile the miRNA expression patterns in HIV-1 transgenic mice (Tg26). Our results showed that 13 miRNAs, which belong to 11 miRNA families, were downregulated in HIVAN when compared with control mice. These miRNAs were classified into 20 functional categories. In in vitro studies, we examined the expression of specific miRNAs in HIV-1 transduced human podocytes. Our results showed that HIV-1 downregulated miRNA expression, specifically of miR-200 and miR-33. These studies suggest that miRNAs contributed to the development of the proliferative phenotype of HIVAN. Further functional analysis of these miRNAs in HIVAN animal model will not only enhance understanding of the pathogenesis but would also lead to the development of therapeutic strategies for HIVAN patients.

Rapamycin-induced modulation of HIV gene transcription attenuates progression of HIVAN.

HIV-associated nephropathy (HIVAN) is the manifestation of HIV gene expression by kidney cells in the presence of specific host factors. Recently, rapamycin (sirolimus) has been demonstrated to modulate the progression of HIVAN. We hypothesized that rapamycin would modulate the progression of HIVAN by attenuating HIV gene expression. To test our hypothesis, three weeks old Tg26 mice (n=6) were administered either vehicle or rapamycin (5 mg/kg, every other day, intraperitoneal) for eight weeks. At the end of the experimental period, the kidneys were harvested. In in vitro studies, human podocytes were transduced with either HIV-1 (NL4-3) or empty vector (EV), followed by treatment with either vehicle or rapamycin. Total RNA and proteins were extracted from renal tissues/cellular lysates and HIV gene transcription/translation was measured by real time PCR and Western blotting studies. Renal histological slides were graded for glomerular sclerosis and tubular dilatation with microcyst formation. Rapamycin attenuated both glomerular and tubular lesions in Tg26 mice. Rapamycin decreased transcription of HIV genes both in renal tissues as well as in HIV-1 transduced podocytes. Our data strongly indicate that HIV-1 long terminal repeat-mediated transcriptional activity was targeted by rapamycin. Rapamycin enhanced podocyte NF-κB and CREB activities but then it decreased AP-1 binding activity. Since expression of HIV genes by kidney cells has been demonstrated to be the key factor in the development HIVAN, it appears that rapamycin-induced altered transcription of HIV genes might have partly contributed to its disease modulating effects.

Transplantation of bone marrow-derived MSCs improves cisplatinum-induced renal injury through paracrine mechanisms.

Mesenchymal stem cells (MSCs) have been reported to preserve renal function in various models of acute kidney injury (AKI). Different routes were used to transplant MSCs but the role of cell transplantation routes in directing outcomes has been unknown. In the present study, we evaluated organ bio-distributions of transplanted MSCs, and correlated survival of transplanted cells with outcomes in mice with cisplatinum-induced AKI. We found that after intravenous administration, MSCs were largely localized in pulmonary capillaries and only a minute fraction of MSCs entered kidneys and the cells survived only transiently. Therefore, we also transplanted MSCs via intraperitoneal and renal subcapsular routes. Transplanted MSCs survived longer in peritoneal cavity and renal subcapsular space. Interestingly, when MSC transplantation was followed by cisplatinum-induced AKI, renal morphology and renal functions were better preserved, irrespective of the cell transplantation route. As transplanted MSCs did not migrate to kidneys from either peritoneal cavity or renal subcapsular space, this finding suggested that migration of cells was not required for the beneficial response. The possibility of indirect mechanisms was confirmed when administration of the conditioned medium from MSCs also protected renal tubular cells from cisplatinum-induced cytotoxicity. We identified presence of over forty regulatory cytokines in the conditioned medium obtained from MSCs. Since paracrine factors released by transplanted cells accounted for improvements, it appears that the route of cell transplantation is not critical for realizing benefits of cell therapy with MSCs in AKI. Studies of specific cytokines secreted by MSCs will help to obtain new therapeutic mechanisms for renal protection.

Inhibition of renin activity slows down the progression of HIV-associated nephropathy.

In the present study, we evaluated the effect of inhibition of renin activity (aliskiren) on the progression of renal lesions in two different mouse models (Vpr and Tg26) of human immunodeficiency virus (HIV)-associated nephropathy (HIVAN). In protocol A, Vpr mice were fed either water (C-VprA) or doxycycline [Doxy (D-VprA)] in their drinking water for 6 wk. In protocols B and C, Vpr mice received either normal saline (C-VprB/C), Doxy + normal saline (D-VprB/C), or Doxy + aliskiren (AD-VprB/C) for 6 wk (protocol B) or 12 wk (protocol C). In protocols D and E, Vpr mice were fed Doxy for 6 wk followed by kidney biopsy. Subsequently, half of the mice were administered either normal saline (D-VprD/E) or aliskiren (AD-VprD/E) for 4 wk (protocol D) or 8 (protocol E) wk. All D-VprA mice showed renal lesions in the form of focal segmental glomerular sclerosis and dilatation of tubules. In protocols B and C, aliskiren diminished both progression of renal lesions and proteinuria. In protocol C, aliskiren also diminished (P < 0.01) the rise in blood urea. In all groups, Doxy-treated mice displayed increased serum ANG I levels (the product of plasma renin activity); on the other hand, all aliskiren-treated mice displayed diminished serum ANG I levels. Renal tissues of D-VprC displayed increased ANG II content; however, aliskiren attenuated renal tissue ANG II production in AD-VprC. In protocol D, AD-VprD showed a 24.2% increase in the number of sclerosed glomeruli compared with 139.2% increase in sclerosed glomeruli in D-VprD (P < 0.01) from their baseline. The attenuating effect of aliskiren on the progression of renal lesions continued in AD-VprE. Aliskiren also diminished blood pressure, proteinuria, and progression of renal lesions in Tg26 mice. These findings indicate that inhibition of renin activity has a potential to slow down the progression of HIVAN.

An optimized color transformation for the analysis of digital images of hematoxylin & eosin stained slides.

Hematoxylin and eosin (H&E) staining is ubiquitous in pathology practice and research. As digital pathology has evolved, the reliance of quantitative methods that make use of H&E images has similarly expanded. For example, cell counting and nuclear morphometry rely on the accurate demarcation of nuclei from other structures and each other. One of the major obstacles to quantitative analysis of H&E images is the high degree of variability observed between different samples and different laboratories. In an effort to characterize this variability, as well as to provide a substrate that can potentially mitigate this factor in quantitative image analysis, we developed a technique to project H&E images into an optimized space more appropriate for many image analysis procedures. We used a decision tree-based support vector machine learning algorithm to classify 44 H&E stained whole slide images of resected breast tumors according to the histological structures that are present. This procedure takes an H&E image as an input and produces a classification map of the image that predicts the likelihood of a pixel belonging to any one of a set of user-defined structures (e.g., cytoplasm, stroma). By reducing these maps into their constituent pixels in color space, an optimal reference vector is obtained for each structure, which identifies the color attributes that maximally distinguish one structure from other elements in the image. We show that tissue structures can be identified using this semi-automated technique. By comparing structure centroids across different images, we obtained a quantitative depiction of H&E variability for each structure. This measurement can potentially be utilized in the laboratory to help calibrate daily staining or identify troublesome slides. Moreover, by aligning reference vectors derived from this technique, images can be transformed in a way that standardizes their color properties and makes them more amenable to image processing.

Modulation of renin angiotensin system predominantly alters sclerotic phenotype of glomeruli in HIVAN.

HIV-associated nephropathy (HIVAN) is a common complication of HIV-1 infection in patients with African ancestry in general and with APOL1 gene risk variants in particular. Although collapsing glomerulopathy is considered a hallmark of HIVAN, significant numbers of glomeruli in patients with HIVAN also display other variants of focal segmental glomerulosclerosis (FSGS). We propose that collapsed glomeruli as well as glomeruli with other variants of FSGS are manifestations of HIVAN and their prevalence depends on associated host factors. We explored the role of the renin-angiotensin system (RAS) in the manifestation of any specific glomerular phenotype in HIVAN. To evaluate the role of the RAS we have used a genetically engineered mouse model of HIVAN (Tg26) with two and four copies of angiotensinogen (Agt) gene (Tg26/Agt2 and Tg26/Agt4). In Tg26/Agt2, 1 out of 6 glomeruli exhibited sclerosed phenotype, whereas 1 out of 25 glomeruli displayed collapsed phenotype; on the other hand, in Tg26/Agt4, 1 out of 3 glomeruli exhibited sclerotic phenotype and only 1 out of 7 glomeruli showed collapsed phenotype. To inhibit the effect of RAS, Tg26/Agt2 were administered captopril, aliskiren, aliskiren plus captopril or aliskiren plus telmisartan by miniosmotic pumps for 4 weeks. In all experimental groups there was a significant reduction in percentage of sclerosed glomeruli and only minimal reduction in collapsed glomeruli compared to normal saline receiving Tg26/Agt2. These findings suggest that the manifestation of the sclerosed phenotype in HIVAN is predominantly dependent on activation of the RAS.