Keratiinit suoliston epiteelisoluissa ja paksusuolisyövän analytiikassa

Keratiinien muodostamat välikokoiset säikeet ovat välttämättömiä suoliston epiteelisolujen toiminnalle. Solun sisäinen keratiiniverkosto vaikuttaa solurakenteen tukemisen lisäksi moniin muihin prosesseihin, esimerkiksi kudosten läpäisevyyteen ja solujen signalointiin. Ihmisellä tavataan kymmeniä eri keratiineja ja monilla epiteeleillä on tunnusomaiset keratiiniprofiilinsa. Suolistoepiteelin keratiiniprofiili eroaa monien muiden elimien vastaavista eikä keskimäärin muutu edes adenokarsinooman kehittyessä tai sen etäpesäkkeissä. Tätä hyödynnetään immunohistokemiaan perustuvassa syöpädiagnostiikassa, jossa suolistolle tyypillisten keratiinien perusteella on tunnistettu paksusuolisyövän etäpesäkkeitä monista eri kudoksista ja näin voitu päästä emokasvaimen jäljille.</p

Keratins modulate colonocyte electrolyte transport via protein mistargeting

The function of intestinal keratins is unknown, although keratin 8 (K8)–null mice develop colitis, hyperplasia, diarrhea, and mistarget jejunal apical markers. We quantified the diarrhea in K8-null stool and examined its physiologic basis. Isolated crypt-units from K8-null and wild-type mice have similar viability. K8-null distal colon has normal tight junction permeability and paracellular transport but shows decreased short circuit current and net Na absorption associated with net Cl secretion, blunted intracellular Cl/HCO3-dependent pH regulation, hyperproliferation and enlarged goblet cells, partial loss of the membrane-proximal markers H,K-ATPase-β and F-actin, increased and redistributed basolateral anion exchanger AE1/2 protein, and redistributed Na-transporter ENaC-γ. Diarrhea and protein mistargeting are observed 1–2 d after birth while hyperproliferation/inflammation occurs later. The AE1/2 changes and altered intracellular pH regulation likely account, at least in part, for the ion transport defects and hyperproliferation. Therefore, colonic keratins have a novel function in regulating electrolyte transport, likely by targeting ion transporters to their cellular compartments

High Volume Hydraulic Fracturing In Michigan Integrated Assessment Final Report

This report is part of the Hydraulic Fracturing in Michigan Integrated Assessment (IA) which has been underway since 2012. The guiding question of the IA is, “What are the best environmental, economic, social, and technological approaches for managing hydraulic fracturing in the State of Michigan?” The purpose of the IA is to present information that: • expands and clarifies the scope of policy options, and • allows a wide range of decision makers to make choices based on their preferences and values. As a result, the IA does not advocate for recommended courses of action. Rather, it presents information about the likely strengths, weaknesses, and outcomes of various options to support informed decision making. The project’s first phase involved the preparation of technical reports on key topics related to hydraulic fracturing in Michigan which were released by the University of Michigan’s Graham Sustainability Institute in September 2013. This document is the final report for the IA. The IA report has been informed by the technical reports, input from an Advisory Committee with representatives from corporate, governmental, and non-governmental organizations, a peer review panel, and numerous public comments received throughout this process. However, the report does not necessarily reflect the views of the Advisory Committee or any other group which has provided input. As with preparation of the technical reports, all decisions regarding content of project analyses and reports have been determined by the IA Report and Integration Teams. While the IA has attempted to provide a comprehensive review of the current status and trends of high volume hydraulic fracturing (HVHF), specifically, in Michigan (the technical reports) and an analysis of policy options (this report) there are certain limitations which must be recognized: • The assessment does not and was not intended to provide a quantitative assessment (human health or environmental) of the potential risks associated with HVHF. Completing such assessments is currently a key point of national discussion related to HVHF despite the challenges of uncertainty and limited available data–particularly baseline data. • The assessment does not provide an economic analysis or a cost-benefit analysis of the presented policy options. While economic strengths and/or weaknesses were identified for many of the options, these should not be viewed as full economic analyses. Additional study would be needed to fully assess the economic impact of various policy actions, including no change of current policy.U-M Graham Sustainability InstituteU-M Energy InstituteU-M Erb Institute for Global Sustainable EnterpriseU-M Risk Science CenterPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113663/1/HF-IA-Final-Report.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/113663/2/HF-IA-Final-Exec-Summary.pdf-1Description of HF-IA-Final-Report.pdf : Full ReportDescription of HF-IA-Final-Exec-Summary.pdf : Executive Summar

Keratin intermediate filaments in the colon: guardians of epithelial homeostasis

Keratin intermediate filament proteins are major cytoskeletal components of the mammalian simple layered columnar epithelium in the gastrointestinal tract. Human colon crypt epithelial cells express keratins 18, 19 and 20 as the major type I keratins, and keratin 8 as the type II keratin. Keratin expression patterns vary between species, and mouse colonocytes express keratin 7 as a second type II keratin. Colonic keratin patterns change during cell differentiation, such that K20 increases in the more differentiated crypt cells closer to the central lumen. Keratins provide a structural and mechanical scaffold to support cellular stability, integrity and stress protection in this rapidly regenerating tissue. They participate in central colonocyte processes including barrier function, ion transport, differentiation, proliferation and inflammatory signaling. The cell-specific keratin compositions in different epithelial tissues has allowed for the utilization of keratin-based diagnostic methods. Since the keratin expression pattern in tumors often resembles that in the primary tissue, it can be used to recognize metastases of colonic origin. This review focuses on recent findings on the biological functions of mammalian colon epithelial keratins obtained from pivotal in vivo models. We also discuss the diagnostic value of keratins in chronic colonic disease and known keratin alterations in colon pathologies. This review describes the biochemical properties of keratins and their molecular actions in colonic epithelial cells and highlights diagnostic data in colorectal cancer and inflammatory bowel disease patients, which may facilitate the recognition of disease subtypes and the establishment of personal therapies in the future

Keratin 7 is a constituent of the keratin network in mouse pancreatic islets and is upregulated in experimental diabetes

Keratin (K) 7 is an intermediate filament protein expressed in ducts and glands of simple epithelial organs and in urothelial tissues. In the pancreas, K7 is expressed in exocrine ducts, and apico-laterally in acinar cells. Here, we report K7 expression with K8 and K18 in the endocrine islets of Langerhans in mice. K7 filament formation in islet and MIN6 β-cells is dependent on the presence and levels of K18. K18-knockout (K18‒/‒) mice have undetectable islet K7 and K8 proteins, while K7 and K18 are downregulated in K8‒/‒ islets. K7, akin to F-actin, is concentrated at the apical vertex of β-cells in wild-type mice and along the lateral membrane, in addition to forming a fine cytoplasmic network. In K8‒/‒ β-cells, apical K7 remains, but lateral keratin bundles are displaced and cytoplasmic filaments are scarce. Islet K7, rather than K8, is increased in K18 over-expressing mice and the K18-R90C mutation disrupts K7 filaments in mouse β-cells and in MIN6 cells. Notably, islet K7 filament networks significantly increase and expand in the perinuclear regions when examined in the streptozotocin diabetes model. Hence, K7 represents a significant component of the murine islet keratin network and becomes markedly upregulated during experimental diabetes.</p

Keratin 7 Is a Constituent of the Keratin Network in Mouse Pancreatic Islets and Is Upregulated in Experimental Diabetes

Keratin (K) 7 is an intermediate filament protein expressed in ducts and glands of simple epithelial organs and in urothelial tissues. In the pancreas, K7 is expressed in exocrine ducts, and apico-laterally in acinar cells. Here, we report K7 expression with K8 and K18 in the endocrine islets of Langerhans in mice. K7 filament formation in islet and MIN6 ?-cells is dependent on the presence and levels of K18. K18-knockout (K18?/?) mice have undetectable islet K7 and K8 proteins, while K7 and K18 are downregulated in K8?/? islets. K7, akin to F-actin, is concentrated at the apical vertex of ?-cells in wild-type mice and along the lateral membrane, in addition to forming a fine cytoplasmic network. In K8?/? ?-cells, apical K7 remains, but lateral keratin bundles are displaced and cytoplasmic filaments are scarce. Islet K7, rather than K8, is increased in K18 over-expressing mice and the K18-R90C mutation disrupts K7 filaments in mouse ?-cells and in MIN6 cells. Notably, islet K7 filament networks significantly increase and expand in the perinuclear regions when examined in the streptozotocin diabetes model. Hence, K7 represents a significant component of the murine islet keratin network and becomes markedly upregulated during experimental diabetes

Absence of keratin 8 or 18 promotes antimitochondrial autoantibody formation in aging male mice

Human mutations in keratin 8 (K8) and keratin 18 (K18), the intermediate filament proteins of hepatocytes, predispose to several liver diseases. K8‐null mice develop chronic liver injury and fragile hepatocytes, dysfunctional mitochondria, and Th2‐type colitis. We tested the hypothesis that autoantibody formation accompanies the liver damage that associates with K8/K18 absence. Sera from wild‐type control, K8‐null, and K18‐null mice were analyzed by immunoblotting and immunofluorescence staining of cell and mouse tissue homogenates. Autoantibodies to several antigens were identified in 81 % of K8‐null male mice 8 mo or older. Similar autoantibodies were detected in aging K18‐null male mice that had a related liver phenotype but normal colon compared with K8‐null mice, suggesting that the autoantibodies are linked to liver rather than colonic disease. However, these autoantibodies were not observed in nontransgenic mice subjected to 4 chronic injury models. The autoantigens are ubiquitous and partition with mitochondria. Mass spectrometry and purified protein analysis identified, mitochondrial HMG‐CoA synthase, aldehyde dehydrogenase, and catalase as the primary autoantigens, and glutamate dehydrogenase and epoxide hydrolase‐2 as additional autoantigens. Therefore, absence of the hepatocyte keratins results in production of anti‐mitochondrial autoantibodies (AMA) that recognize proteins involved in energy metabolism and oxidative stress, raising the possibility that AMA may be found in patients with keratin mutations that associate with liver and other diseases.—Toivola, D. M., Habtezion, A., Misiorek, J. O., Zhang, L., Nyström, J. H., Sharpe, O., Robinson, W. H., Kwan, R., Omary, M. B. Absence of keratin 8 or 18 promotes antimitochondrial autoantibody formation in aging male mice. FASEB J. 29, 5081–5089 (2015). www.fasebj.orgPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154363/1/fsb2029012032.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154363/2/fsb2029012032-sup-0002.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154363/3/fsb2029012032-sup-0003.pd

Keratins Are Altered in Intestinal Disease-Related Stress Responses

Keratin (K) intermediate filaments can be divided into type I/type II proteins, which form obligate heteropolymers. Epithelial cells express type I-type II keratin pairs, and K7, K8 (type II) and K18, K19 and K20 (type I) are the primary keratins found in the single-layered intestinal epithelium. Keratins are upregulated during stress in liver, pancreas, lung, kidney and skin, however, little is known about their dynamics in the intestinal stress response. Here, keratin mRNA, protein and phosphorylation levels were studied in response to murine colonic stresses modeling human conditions, and in colorectal cancer HT29 cells. Dextran sulphate sodium (DSS)-colitis was used as a model for intestinal inflammatory stress, which elicited a strong upregulation and widened crypt distribution of K7 and K20. K8 levels were slightly downregulated in acute DSS, while stress-responsive K8 serine-74 phosphorylation (K8 pS74) was increased. By eliminating colonic microflora using antibiotics, K8 pS74 in proliferating cells was significantly increased, together with an upregulation of K8 and K19. In the aging mouse colon, most colonic keratins were upregulated. In vitro, K8, K19 and K8 pS74 levels were increased in response to lipopolysaccharide (LPS)-induced inflammation in HT29 cells. In conclusion, intestinal keratins are differentially and dynamically upregulated and post-translationally modified during stress and recovery.</p

Keratin intermediate filaments in the colon: guardians of epithelial homeostasis

Keratin intermediate filament proteins are major cytoskeletal components of the mammalian simple layered columnar epithelium in the gastrointestinal tract. Human colon crypt epithelial cells express keratins 18, 19 and 20 as the major type I keratins, and keratin 8 as the type II keratin. Keratin expression patterns vary between species, and mouse colonocytes express keratin 7 as a second type II keratin. Colonic keratin patterns change during cell differentiation, such that K20 increases in the more differentiated crypt cells closer to the central lumen. Keratins provide a structural and mechanical scaffold to support cellular stability, integrity and stress protection in this rapidly regenerating tissue. They participate in central colonocyte processes including barrier function, ion transport, differentiation, proliferation and inflammatory signaling. The cell-specific keratin compositions in different epithelial tissues has allowed for the utilization of keratin-based diagnostic methods. Since the keratin expression pattern in tumors often resembles that in the primary tissue, it can be used to recognize metastases of colonic origin. This review focuses on recent findings on the biological functions of mammalian colon epithelial keratins obtained from pivotal in vivo models. We also discuss the diagnostic value of keratins in chronic colonic disease and known keratin alterations in colon pathologies. This review describes the biochemical properties of keratins and their molecular actions in colonic epithelial cells and highlights diagnostic data in colorectal cancer and inflammatory bowel disease patients, which may facilitate the recognition of disease subtypes and the establishment of personal therapies in the future