Project description:Kidney transplant recipients with biopsy-proven microvascular injury (MVI) have increased risk for allograft failure. MVI is often caused by antibody-mediated injury that is resistant to available treatments. Current diagnostic methods are also inadequate, with interobserver variability in traditional pathology reads, variable assessment of circulating donor-specific antibody between HLA laboratories, and peritubular capillary C4d staining. Molecular assessments of kidney biopsies can provide improved sensitivity for diagnosing MVI and other allograft pathology, while improving reproducibility and objectivity. Most molecular classifiers have been based on whole genome sequencing to develop diagnostic tests, but have provided limited therapeutic targets. In this study, we pursued a candidate gene approach to measure WNT pathway genes in residual clinical FFPE biopsies with and without MVI. We focused on the WNT pathway because of previous translational studies that implicated this pathway in chronic renal allograft injury as well as vascular injury in native chronic kidney disease. Case-control study of 95 residual FFPE biopsies with MVI (g+ptc score >= 2, n=50) or Stable (g+ptc score < 2 and no other major abnormalities, n=45). Biopsies were retrieved from a biorepository of over 500 kidney transplant biopsies. We compared expression of 180 WNT pathway genes and 30 custom skipe-in targets (derived from previous studies of endothelial injury in transplantation) between MVI and Stable groups, with correction for multiple comparisons using FDR < 5%. This dataset is part of the TransQST collection.
Project description:Kidney transplant recipients with biopsy-proven microvascular injury (MVI) have increased risk for allograft failure. MVI is often caused by antibody-mediated injury that is resistant to available treatments. Current diagnostic methods are also inadequate, with interobserver variability in traditional pathology reads, variable assessment of circulating donor-specific antibody between HLA laboratories, and peritubular capillary C4d staining. Molecular assessments of kidney biopsies can provide improved sensitivity for diagnosing MVI and other allograft pathology, while improving reproducibility and objectivity. Most molecular classifiers have been based on whole genome sequencing to develop diagnostic tests, but have provided limited therapeutic targets. In this study, we pursued a candidate gene approach to measure WNT pathway genes in residual clinical FFPE biopsies with and without MVI. We focused on the WNT pathway because of previous translational studies that implicated this pathway in chronic renal allograft injury as well as vascular injury in native chronic kidney disease.
Project description:Hypothesis and proof of concept:
Our hypothesis is that increase in cellular iron import proteins (TfR1, DMT1) occur early in the adenoma-carcinoma sequence through mutations in APC and lead to cellular iron loading. As demonstrated in our previous work the effects of this iron loading is to mediate increased Wnt signalling resulting in c-myc induction. This in turn serves to increase the expression of iron import proteins (TfR1, DMT1) and decrease the expression of iron export (ferroportin [FPN]) and storage (ferritin) proteins. Such a hypothesis explains how Wnt signalling controls iron metabolism and ensures that there is adequate cellular iron for ATP generation and cellular proliferation.
Experimental design:
To test such a hypothesis we aim to prospectively collect the following colorectal tissue from patients attending for colonoscopy:
1. Normal colonic mucosa in patients with no colorectal pathology (n = 30)
2. Polyps and matched normal colon (n = 30)
3. Colorectal cancers and matched normal colon (n = 30)
We also intend to collect serum and urine from the following patient groups:
4. Normal colonoscopy (n = 30)
5. Colorectal adenomas (n = 30)
6. Colorectal cancers (n = 30)
Primary outcome(s): Measured at baseline, using the expression of proteins in the tissue and serum to detect the cellular and systemic iron transport proteins. The techniques used will include mass spectrometry, western blotting, real time PCR and immunohistochemistry.
Project description:Microarray analysis of human kidneys with acute kidney injury (AKI) has been limited because such kidneys are seldom biopsied. However, all kidney transplants experience AKI, and early kidney transplants without rejection are an excellent model for human AKI: they are screened to exclude chronic kidney disease, frequently biopsied, and have extensive follow-up. We used histopathology and microarrays to compare indication biopsies from 28 transplants with AKI to 11 pristine protocol biopsies of stable transplants. Kidneys with AKI showed increased expression of 394 injury-repair response associated transcripts, including many known epithelial injury molecules (e.g. ITGB6, LCN2), tissue remodeling molecules (e.g. VCAN), and inflammation molecules (S100A8, ITGB3). Many other genes also predict the phenotype, depending on statistical filtering rules, including AKI biomarkers as HAVCR1 and IL18. Most mouse orthologs of the top injury-repair transcripts were increased in published mouse AKI models. Pathway analysis of the injury-repair transcripts revealed similarities to cancer, development, and cell movement. The injury-repair transcript score AKI kidneys correlated with reduced function, future recovery, brain death, and need for dialysis, but not future graft loss. In contrast, histologic features of "acute tubular injury" did not correlate with function or with the molecular changes. Thus the injury-repair associated transcripts represent a massive coordinate injury-repair response of kidney parenchyma to AKI, similar to mouse AKI models, and provide an objective measure for assessing the severity of AKI in kidney biopsies and validation for the use of many AKI biomarkers.
Project description:Microarray analysis of human kidneys with acute kidney injury (AKI) has been limited because such kidneys are seldom biopsied. However, all kidney transplants experience AKI, and early kidney transplants without rejection are an excellent model for human AKI: they are screened to exclude chronic kidney disease, frequently biopsied, and have extensive follow-up. We used histopathology and microarrays to compare indication biopsies from 28 transplants with AKI to 11 pristine protocol biopsies of stable transplants. Kidneys with AKI showed increased expression of 394 injury-repair response associated transcripts, including many known epithelial injury molecules (e.g. ITGB6, LCN2), tissue remodeling molecules (e.g. VCAN), and inflammation molecules (S100A8, ITGB3). Many other genes also predict the phenotype, depending on statistical filtering rules, including AKI biomarkers as HAVCR1 and IL18. Most mouse orthologs of the top injury-repair transcripts were increased in published mouse AKI models. Pathway analysis of the injury-repair transcripts revealed similarities to cancer, development, and cell movement. The injury-repair transcript score AKI kidneys correlated with reduced function, future recovery, brain death, and need for dialysis, but not future graft loss. In contrast, histologic features of "acute tubular injury" did not correlate with function or with the molecular changes. Thus the injury-repair associated transcripts represent a massive coordinate injury-repair response of kidney parenchyma to AKI, similar to mouse AKI models, and provide an objective measure for assessing the severity of AKI in kidney biopsies and validation for the use of many AKI biomarkers. AKI biopsies sample names and CEL files are from GSE21374. All consenting renal transplant patients undergoing biopsies for cause as standard of care between 09/2004 and 10/2007 at the university of Alberta or between 11/2006 and 02/2007 at the University of Illinois were included in the analysis. In addition to the cores required for standard histopathology, we collected one core for gene expression studies. the relationship between gene expression in the biopsy and subsequent graft loss was analyzed. This dataset is part of the TransQST collection.
Project description:The function of the FAM83F protein, like the functions of many members of the FAM83 family, is poorly understood. Here we show that injection of Fam83f mRNA into Xenopus embryos causes axis duplication, a phenotype indicative of enhanced Wnt signalling. Consistent with this, overexpression of FAM83F activates Wnt signalling, whilst ablation of FAM83F from human colorectal cancer (CRC) cells attenuates it. We demonstrate that FAM83F is farnesylated and interacts and co-localises with CK1α at the plasma membrane. This interaction with CK1α is essential for FAM83F to activate Wnt signalling, and FAM83F mutants that do not interact with CK1α fail to induce axis duplication in Xenopus embryos and to activate Wnt signalling in cells. FAM83F acts upstream of GSK-3β, because the attenuation of Wnt signalling caused by loss of FAM83F can be rescued by GSK-3 inhibition. Introduction of a farnesyl-deficient mutant of FAM83F in cells through CRISPR/Cas9 genome editing redirects the FAM83F-CK1α complex away from the plasma membrane and significantly attenuates Wnt signalling, indicating that FAM83F exerts its effects on Wnt signalling at the plasma membrane.
Project description:The aim of the present work was to investigate the effect of monensin on the in vitro growth of T. gondii tachyzoites and on the host cells (human brain microvascular endothelial cells - hBMECs). The hypotheses were that (1) inhibition of the WNT signalling pathway by monensin can reduce the growth of T. gondii infecting human brain microvascular endothelial cells (hBMECs) and (2) by suppression of the growth of T. gondii using monensin, impairment of the BBB integrity can be restored (3) inhibition of WNT pathway by monensin can be detected by microarray experiment.