Background In Henoch–Schönlein nephritis (HSN), a risk factor for unfavorable outcome is prolonged proteinuria, but the value of renal biopsies in prognosis assessment is debatable. Methods We evaluated serial renal biopsies from 26 HSN patients. Follow-up biopsy occurred at median 2.1 years after diagnostic biopsy. Patients formed two groups at the follow-up biopsy: patients without proteinuria (group I; n = 11) and with proteinuria (group II; n = 15). Biopsies underwent evaluation according to three classifications: International Study of Kidney Disease in Children (ISKDC), Oxford (MEST-C), and semiquantitative classification (SQC) including an activity and chronicity score. Analysis also included expression of pro-fibrotic (alpha-smooth muscle actin and vimentin) and inflammatory (P-selectin glycoprotein ligand-1) molecules in the diagnostic biopsy specimens. Definition of unfavorable outcome was active renal disease or reduced renal function at last follow-up. Results Between the biopsies, SQC chronicity score increased in 22 (85%) patients, whereas activity score and ISKDC grade decreased in 21 (81%) and 17 (65%), respectively. Of the MEST-C parameters, endocapillary proliferation (from 83 to 13%; p < 0.001) and crescents (from 63 to 25%; p = 0.022) showed significant reduction, and segmental glomerulosclerosis (from 38 to 79%; p = 0.006) significant increment. These changes occurred similarly in groups I and II. Expression of the pro-fibrotic and inflammatory molecules showed no clinically significant differences between groups I and II. None in group I and five (33%) patients in group II had unfavorable outcome ( p = 0.053). Conclusions Our results suggest that follow-up biopsies provide limited additional information to clinical symptoms in HSN outcome prediction.

Histological findings from primary kidney biopsies were correlated with patient outcomes in a national cohort of paediatric Henoch–Schönlein nephritis (HSN) patients.

Mitochondrial fatty acid synthesis (mtFAS) is an underappreciated but highly conserved metabolic process, indispensable for mitochondrial respiration. It was recently reported that dysfunction of mtFAS causes childhood onset of dystonia and optic atrophy in humans (MEPAN). To study the role of mtFAS in mammals, we generated three different mouse lines with modifications of the Mecr gene, encoding mitochondrial enoyl-CoA/ACP reductase (Mecr). A knock-out-first type mutation, relying on insertion of a strong transcriptional terminator between the first two exons of Mecr, displayed embryonic lethality over a broad window of time and due to a variety of causes. Complete removal of exon 2 or replacing endogenous Mecr by its functional prokaryotic analogue fabI (Mecrtm(fabI)) led to more consistent lethality phenotypes and revealed a hypoplastic placenta. Analyses of several mitochondrial parameters indicate that mitochondrial capacity for aerobic metabolism is reduced upon disrupting mtFAS function. Further analysis of the synthetic Mecrtm(fabI) models disclosed defects in development of placental trophoblasts consistent with disturbed peroxisome proliferator-activated receptor signalling. We conclude that disrupted mtFAS leads to deficiency in mitochondrial respiration, which lies at the root of the observed pantropic effects on embryonic and placental development in these mouse models.

Tubulointerstitial nephritis (TIN) is an inflammatory disease of unknown pathogenesis. To evaluate a possible role of regulatory T cells (Tregs) in the pathophysiology of TIN with (TINU) and without uveitis, we investigated the presence and quantity of FOXP3(+) T regulatory lymphocytes in diagnostic kidney biopsies from pediatric patients. A total of 33 patients (14 TIN and 19 TINU) were enrolled. The quantity of CD4(+), FOXP3(+) and double-positive T cells in formalin-fixed kidney biopsies was determined using double label immunohistochemistry with anti-human CD4 and FOXP3 antibodies. FOXP3 staining was successful in all 33 patients. In patients with chronic uveitis, the density of FOXP3(+) cells was significantly lower (p = 0.046) than in TIN patients without uveitis or with uveitis lasting < 3 months. CD4(+) staining was successful in 23 patients. The density of all lymphocytes (CD4(+), CD4(+)FOXP3(+) and FOXP3(+) cells) was significantly lower (p = 0.023) in patients with chronic uveitis than in other patients. FOXP3(+) T cells are present in kidney biopsy samples from TIN and TINU patients. In patients with chronic uveitis, the density of FOXP3(+) T cells is significantly lower than in other patients, suggesting a different pathomechanism for these clinical conditions.

As the second most common skin malignancy, cutaneous squamous cell carcinoma (cSCC) is an increasing health concern, while its pathogenesis at molecular level remains largely unknown. We studied the expression and localisation of two homologous basement membrane (BM) collagens, types XV and XVIII, at different stages of cSCC. These collagens are involved in angiogenesis and tumorigenesis, but their role in cancer development is incompletely understood. Quantitative RT-PCR analysis revealed upregulation of collagen XVIII, but not collagen XV, in primary cSCC cells in comparison with normal human epidermal keratinocytes. In addition, the Ha-ras-transformed invasive cell line II-4 expressed high levels of collagen XVIII mRNA, indicating upregulation in the course of malignant transformation. Immunohistochemical analyses of a large human tissue microarray material showed that collagen XVIII is expressed by tumor cells from grade 1 onwards, while keratinocytes in normal skin and in premalignant lesions showed negative staining for it. Collagen XV appeared instead as deposits in the tumor stroma. Our findings in human cSCCs and in mouse cSCCs from the DMBA-TPA skin carcinogenesis model showed that collagen XVIII, but not collagen XV or the BM markers collagen IV or laminin, was selectively reduced in the tumor vasculature, and this decrease associated significantly with cancer progression. Our results demonstrate that collagens XV and XVIII are expressed in different sites of cSCC and may contribute in a distinct manner to processes related to cSCC tumorigenesis, identifying these collagens as potential biomarkers in the disease.

Collagen XVII has a well-established role as an adhesion molecule and a cell surface receptor located in the type I hemidesmosome of stratified epithelia. Its ectodomain is constitutively shed from the cell surface and suggested to regulate the adhesion, migration, and signaling of cutaneous epithelial cells. Collagen XVII was not previously thought to be expressed by colon epithelial cells. Immunohistochemical analysis of tissue microarray samples of 141 cases of colorectal carcinoma showed that collagen XVII is expressed in normal human colonic mucosa and colorectal carcinoma. In colorectal carcinoma, increased collagen XVII expression was significantly associated with higher TNM stage. It also correlated with infiltrative growth pattern and tumor budding as well as lymph node and distant metastasis. Increased collagen XVII expression was associated with decreased disease-free and cancer-specific survival. Immunofluorescence staining of collagen XVII and its well-known binding partner laminin γ2 chain demonstrated a partial colocalization in normal and tumor tissue. In vitro, the overexpression of murine collagen XVII promoted the invasion of CaCo-2 colon carcinoma cells through Matrigel (BD Biosciences; Bedford, MA). To conclude, this study reports for the first time the expression of collagen XVII in colon epithelium and the association of increased collagen XVII immunoexpression with poor outcome in colorectal carcinoma.

Long-term fructose consumption has been shown to evoke leptin resistance, to elevate triglyceride levels and to induce insulin resistance and hepatic steatosis. Autophagy has been suggested to function in processes such as lipid storage in adipose tissue and inflammation in liver. Autophagy and the leptin system have also been suggested to regulate each other. This study aimed to identify the changes caused by fetal undernourishment and postnatal fructose diet in the gene expression of leptin, its receptors (LEPR-a, LEPR-b, LEPR-c, LEPR-e and LEPR-f) and autophagy genes in the white adipose tissue (WAT) and liver of adult male rats in order to clarify the mechanism behind the metabolic alterations. The data clearly revealed that the long-term postnatal fructose diet decreased leptin levels (p < 0.001), LEPR (p < 0.001), especially LEPR-b (p = 0.011) and LEPR-f (p = 0.005), as well as SOCS3 (p < 0.001), ACC (p = 0.006), ATG7 (p < 0.001), MAP1LC3β (p < 0.001) and LAMP2 (p = 0.004) mRNA expression in WAT. Furthermore, LEPR (p < 0.001), especially LEPR-b (p = 0.001) and LEPR-f (p < 0.001), ACC (p = 0.010), ATG7 (p = 0.024), MAP1LC3β (p = 0.003) and LAMP2 (p < 0.001) mRNA expression in the liver was increased in fructose-fed rats. In addition, the LEPR expression in liver and MAP1LC3β expression in WAT together explained 55.7 % of the variation in the plasma triglyceride levels of the rats (R adj. 2  = 0.557, p < 0.001). These results, together with increased p62 levels in WAT (p < 0.001), could indicate decreased adipose tissue lipid storing capacity as well as alterations in liver metabolism which may represent a plausible mechanism through which fructose consumption could disturb lipid metabolism and result in elevated triglyceride levels.

The kidney filtration barrier consists of the capillary endothelium, the glomerular basement membrane and the slit diaphragm localized between foot processes of neighbouring podocytes. We report that collagen XVII, a transmembrane molecule known to be required for epithelial adhesion, is expressed in podocytes of normal human and mouse kidneys and in endothelial cells of the glomerular filtration barrier. Immunoelectron microscopy has revealed that collagen XVII is localized in foot processes of podocytes and in the glomerular basement membrane. Its role in kidney has been analysed in knockout mice, which survive to birth but have high neonatal mortality and skin blistering and structural abnormalities in their glomeruli. Morphometric analysis has shown increases in glomerular volume fraction and surface densities of knockout kidneys, indicating an increased glomerular amount in the cortex. Collagen XVII deficiency causes effacement of podocyte foot processes; however, major slit diaphragm disruptions have not been detected. The glomerular basement membrane is split in areas in which glomerular and endothelial basement membranes meet. Differences in the expression of collagen IV, integrins α3 or β1, laminin α5 and nephrin have not been observed in mutant mice compared with controls. We propose that collagen XVII has a function in the attachment of podocyte foot processes to the glomerular basement membrane. It probably contributes to podocyte maturation and might have a role in glomerular filtration.

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endoplasmic reticulum TO THE EDITOR Transmembrane collagen XVII is a hemidesmosomal component that is essential for the anchorage of epithelial cells to the basement membrane (Franzke et al., 2005Franzke C.W. Bruckner P. Bruckner-Tuderman L. Collagenous transmembrane proteins: recent insights into biology and pathology.J Biol Chem. 2005; 280: 4005-4008Crossref PubMed Scopus (147) Google Scholar). Mutations in the collagen XVII gene, COL17A1, are associated with junctional epidermolysis bullosa. The majority of COL17A1 mutations lead to a premature termination codon and the absence of collagen XVII in the skin, whereas missense mutations or deletions of amino acids are less common (Aumailley et al., 2006Aumailley M. Has C. Tunggal L. Bruckner-Tuderman L. Molecular basis of inherited blistering skin disorders, and therapeutic implications.Expert Rev Mol Med. 2006; 8: 1-21Crossref PubMed Scopus (66) Google Scholar; Varki et al., 2006Varki R. Sadowski S. Pfender E. Uitto J. Epidermolysis bullosa. Molecular genetics of the junctional and hemidesmosomal variants.J Med Genet. 2006; 43: 641-652Crossref PubMed Scopus (129) Google Scholar). Analogously to other collagens, the glycine substitutions located in the largest collagenous domain of collagen XVII, Col15, interrupt the triple-helix formation and lead to partial unfolding of the ectodomain (Väisänen et al., 2005Väisänen L. Has C. Franzke C. Hurskainen T. Tuomi M.L. Bruckner-Tuderman L. et al.Molecular mechanisms of junctional epidermolysis bullosa: Col15 domain mutations decrease the thermal stability of collagen XVII.J Invest Dermatol. 2005; 125: 1112-1118Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar). However, it is possible that glycine substitutions also interfere with the transport of collagen XVII within the secretory pathway and its post-translational modifications and membrane targeting. Here we have analyzed the subcellular localization of collagen XVII with glycine substitutions G539E, G609D, G612R, G627V, and G633D, and the in-frame deletion of amino acids 779–787 (Δ779–787) expressed transiently in COS-7 cells (McGrath et al., 1996McGrath J.A. Gatalica B. Li K. Giles M. Dunnill S. McMillan J. et al.Compound heterozygosity for a dominant glycine substitution and a recessive internal duplication mutation in type XVII collagen gene results in junctional epidermolysis bullosa and abnormal dentition.Am J Pathol. 1996; 148: 1787-1796PubMed Google Scholar; Chavanas et al., 1997Chavanas S. Gache Y. Tadini G.L. Pulkkinen L. Uitto J. Ortonne J.P. et al.A homozygous in-frame deletion in the collagenous domain of bullous pemphigoid antigen BP180 (type XVII collagen) causes generalized atrophic benign epidermolysis bullosa.J Invest Dermatol. 1997; 109: 74-78Crossref PubMed Scopus (41) Google Scholar; Floeth et al., 1998Floeth M. Fiedorowich J. Schäcke H. Hammami-Hauasli N. Owaribe K. Trüeb R.M. et al.Novel homozygous and compound heterozygous COL17A1 mutations associated with junctional epidermolysis bullosa.J Invest Dermatol. 1998; 111: 528-533Crossref PubMed Scopus (29) Google Scholar; Tasanen et al., 2000Tasanen K. Floeth M. Schumann H. Bruckner-Tuderman L. Hemizygosity for a glycine substitution in collagen XVII: unfolding and degradation of the ectodomain.J Invest Dermatol. 2000; 115: 207-212Crossref PubMed Scopus (26) Google Scholar; Väisänen et al., 2005Väisänen L. Has C. Franzke C. Hurskainen T. Tuomi M.L. Bruckner-Tuderman L. et al.Molecular mechanisms of junctional epidermolysis bullosa: Col15 domain mutations decrease the thermal stability of collagen XVII.J Invest Dermatol. 2005; 125: 1112-1118Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar). Wild-type collagen XVII was localized in the cell plasma membrane in immunofluorescence staining with the collagen XVII-specific polyclonal NC16A antibody (Figure 1a). Interestingly, the molecules carrying glycine substitutions G539E, G609D, or G627V were detectable mostly as patchy intracellular staining; there was less membrane-bound staining (Figure 1b and c). In immunoelectron microscopy analysis of cells transfected with wild-type collagen XVII, gold labeling was detected in the plasma membrane (Figure 1e). In cells transfected with the constructs containing the mutations G609D and G627V, gold particles were abundant in the endoplasmic reticulum (ER) (Figure 1f), but few gold particles were seen in the plasma membrane (not shown). However, in cells transfected with the construct containing the mutation G539E, gold particles were distributed in both the ER and cell membrane (Figure 1g and h). In the ER, collagens undergo multiple specific post-translational modifications, including hydroxylation of certain proline and lysine residues and glycosylation of some of the hydroxylysine residues, and fold into their native triple-helical conformation before export to the Golgi complex. Accumulation of mutated polypeptides in ER may expose them to overhydroxylation and overglycosylation, as shown for procollagens I (Baldwin et al., 1989Baldwin C.T. Constantinou C.D. Dumars K.W. Prockop D.J. A single base mutation that converts glycine 907 of the α2(I) chain of type I procollagen to aspartate in a lethal variant of osteogenesis imperfecta.J Biol Chem. 1989; 264: 3002-3006Abstract Full Text PDF PubMed Google Scholar; Westerhausen et al., 1990Westerhausen A. Kishi J. Prockop D.J. Mutations that substitute serine for glycine α1-598 and glycine α1-631 in type I procollagen.J Biol Chem. 1990; 265: 13995-14000Abstract Full Text PDF PubMed Google Scholar) and III (Tromp et al., 1989Tromp G. Kuivaniemi H. Stolle C. Pope F.M. Prockop D.J. Single base mutation in the type III procollagen gene that converts the codon for glycine 883 to aspartate in a mild variant of Ehlers-Danlos syndrome IV.J Biol Chem. 1989; 264: 19313-19317Abstract Full Text PDF PubMed Google Scholar). To investigate the post-translational modifications of mutated collagen XVII, the transfected cells and their culture media were analyzed by immunoblotting using 4–15% gradient gels and the NC16A antibody. Full-length collagen XVII molecules, both wild-type and mutated, migrated similarly. In contrast, the shed ectodomains containing the G609D, G612R, G627V, or G633D mutation migrated somewhat more slowly than the wild type (Figure 2a). In contrast, neither the mutant G539E nor Δ779–787 exhibited abnormal migration. The retarded mobility of the mutated polypeptides with Col15 glycine substitutions suggests post-translational overmodification due to conformational changes and disturbed triple-helix formation in the Col15 domain, but the ER accumulation alone due to NC16A glycine substitution G539E does not lead to overprocessing of mutated collagen XVII polypeptide. N-glycosylation is required for accurate cell surface integration of collagen XVII (Franzke et al., 2006Franzke C.W. Has C. Schulte C. Huilaja L. Tasanen K. Aumailley M. et al.C-terminal truncation impairs glycosylation of transmembrane collagen XVII and leads to intracellular accumulation.J Biol Chem. 2006; 281: 30260-30268Crossref PubMed Scopus (22) Google Scholar). To analyze how collagen XVII passes through the ER and the Golgi apparatus, we assessed the ability of two endoglycosidases, Endo H and peptide N-glycosidase F, to remove N-linked sugars from mutated collagen XVII molecules. Although N-linked sugars remain sensitive to N-glycosidase F, they become resistant to Endo H after they are modified in the medial Golgi. Digestion with N-glycosidase F resulted in reduction of the molecular mass of both full-length and shed forms of wild-type and mutated collagen XVII (Figure S1a). In contrast, all forms were resistant to Endo H deglycosylation (Figure S1b). Taken together, these results indicate that glycine substitution mutations or Δ779–787 do not interfere with the N-glycosylation of collagen XVII and its further procession through the medial Golgi apparatus. Thus, the partial intracellular retention of glycine-substituted collagen XVII molecules is not due to disturbed N-glycosylation. Download .pdf (.48 MB) Help with pdf files Supplementary Figure S1Glycosidase digestions of mutated collagen XVII. For deglycosylation 100 μl of cell extract and 200 μl of cell media were treated with 2percnt; β-mercaptoethanol for 10 minutes at 60°C and digested overnight at 37°C with 5000 U/ml N-glycosidase F or 2.5 U/ml endoglycosidase H (both from New England Biolabs, Ipswich, MA). (a) Both the full-length forms and the shed ectodomains of wild-type, glycine-substituted and 779-787 collagen XVII molecules were sensitive to the N-glycosidase F digestions. (b) Similarly to the wild-type collagen XVII, the full-length forms and the shed ectodomains of glycine-substituted and 779-787 molecules were resistant to endoglycosidase H digestions. A post-translational process that distinguishes the transmembrane collagens from other members of the collagen superfamily is regulated through proteolysis of the ectodomain from the cell surface. The ectodomain of collagen XVII is shed from the cell surface by a disintegrin and metalloproteases (ADAMs) (Franzke et al., 2002Franzke C.W. Tasanen K. Schäcke H. Zhou Z. Tryggvason K. Mauch C. et al.Transmembrane collagen XVII, an epithelial adhesion protein, is shed from the cell surface by ADAMs.EMBO J. 2002; 21: 5026-5035Crossref PubMed Scopus (188) Google Scholar, Franzke et al., 2004Franzke C.W. Tasanen K. Borradori L. Huotari V. Bruckner-Tuderman L. Shedding of collagen XVII/BP180: structural motifs influence cleavage from cell surface.J Biol Chem. 2004; 279: 24521-24529Crossref PubMed Scopus (67) Google Scholar). To analyze the effect of COL17A1 mutations on ectodomain release, intact transfected COS-7 cells were surface biotinylated. Similar to the authentic ectodomain in keratinocytes, the wild-type ectodomain was detectable within 2 hours in the cell culture medium (Figure 2b). The glycine substitutions delayed shedding, as ectodomains with the G539E, G609D, and G627V mutations were not notably detectable in the media until after 6 hours (Figure 2b and c). In contrast, Δ779–787 was shed similarly to the wild type (Figure 2b and c). Delayed shedding might be explained by partial retention of mutated collagen XVII polypeptides in ER, as the signals were quite similar to those of the wild type after 4 hours. Alternatively, structural changes in the NC16A domain due to mutations in the NC16A or Col15 may affect ectodomain shedding (Väisänen et al., 2005Väisänen L. Has C. Franzke C. Hurskainen T. Tuomi M.L. Bruckner-Tuderman L. et al.Molecular mechanisms of junctional epidermolysis bullosa: Col15 domain mutations decrease the thermal stability of collagen XVII.J Invest Dermatol. 2005; 125: 1112-1118Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar). In the case of fibrillar collagens, glycine substitutions lead to the production of structurally altered polypeptides and usually cause a more severe phenotype than null mutations (Myllyharju and Kivirikko, 2001Myllyharju J. Kivirikko K.I. Collagens and collagen related diseases.Ann Med. 2001; 33: 7-21Crossref PubMed Scopus (549) Google Scholar). Collagen XVII is able to better tolerate glycine substitutions, which are associated with a milder phenotype than null mutations (Väisänen et al., 2005Väisänen L. Has C. Franzke C. Hurskainen T. Tuomi M.L. Bruckner-Tuderman L. et al.Molecular mechanisms of junctional epidermolysis bullosa: Col15 domain mutations decrease the thermal stability of collagen XVII.J Invest Dermatol. 2005; 125: 1112-1118Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar; Aumailley et al., 2006Aumailley M. Has C. Tunggal L. Bruckner-Tuderman L. Molecular basis of inherited blistering skin disorders, and therapeutic implications.Expert Rev Mol Med. 2006; 8: 1-21Crossref PubMed Scopus (66) Google Scholar; Varki et al., 2006Varki R. Sadowski S. Pfender E. Uitto J. Epidermolysis bullosa. Molecular genetics of the junctional and hemidesmosomal variants.J Med Genet. 2006; 43: 641-652Crossref PubMed Scopus (129) Google Scholar). Our data suggest that glycine substitutions in the Col15 domain interfere with the triple-helix formation, transmembrane targeting, and ectodomain shedding of collagen XVII, and that these disturbances lead to skin blistering. G539E located within the NC16A domain causes intracellular protein accumulation and delayed shedding similar to Col15 glycine substitutions, but does not lead to overmodification of mutated polypeptide. Thus, it is obvious that there are other, still unknown molecular mechanisms contributing to biological phenotypes of these mutations, given that both G539E and Δ779–787 result in the complete absence of collagen XVII in patients’ skin, whereas the glycine substitutions in Col15 cause reduced collagen XVII expression (McGrath et al., 1996McGrath J.A. Gatalica B. Li K. Giles M. Dunnill S. McMillan J. et al.Compound heterozygosity for a dominant glycine substitution and a recessive internal duplication mutation in type XVII collagen gene results in junctional epidermolysis bullosa and abnormal dentition.Am J Pathol. 1996; 148: 1787-1796PubMed Google Scholar; Tasanen et al., 2000Tasanen K. Floeth M. Schumann H. Bruckner-Tuderman L. Hemizygosity for a glycine substitution in collagen XVII: unfolding and degradation of the ectodomain.J Invest Dermatol. 2000; 115: 207-212Crossref PubMed Scopus (26) Google Scholar; Väisänen et al., 2005Väisänen L. Has C. Franzke C. Hurskainen T. Tuomi M.L. Bruckner-Tuderman L. et al.Molecular mechanisms of junctional epidermolysis bullosa: Col15 domain mutations decrease the thermal stability of collagen XVII.J Invest Dermatol. 2005; 125: 1112-1118Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar). The authors state no conflict of interest. We thank Anja Mattila for excellent technical assistance and Seija Leskelä for expert help with the illustrations. Risto Bloigu is acknowledged for his excellent advice in statistics. This study was supported by the Finnish National Graduate School of Clinical Investigation, the Finnish Dermatology Society, the Oulu University Pharmacy Foundation, the Oskar Öflund Foundation, and the Finnish–Norwegian Medical Foundation to LH; by the Finnish Medical Foundation, the Alexander von Humbolt Foundation, the Rene Touraine Foundation, and the Oulu University Hospital to KT; and by grants from the German Research Foundation (Br1475/9-1) and the Network of Excellence “Epidermolysis bullosa” via the German Federal Ministry of Education and Research to LB-T. Supplementary Materials and Methods Figure S1. Glycosidase digestion of mutated collagen XVII. Download .pdf (.06 MB) Help with pdf files Supplementary Material

Major cause of prematurity is spontaneous preterm birth (PTB) associated with intrauterine inflammation. Our aim was to establish a model of endotoxin Lipopolysaccharide-induced PTB of live-born pups and to study early immune activation in fetal and maternal compartments. Expression of several proteins that bind microbes (Toll-like receptors TLR4, TLR2; surfactant proteins SP-A, SP-D) was analyzed. At 16 or 17 d of gestation, C57BL/6 dams received a single dose of intraperitoneal LPS, leading to PTB within 17 h. Cytokine levels increased in maternal serum, followed by a modest increase in fetal serum and in amniotic fluid. In uterus, placenta, and fetal membranes, LPS mostly increased the expressions of TLR, SPs, and cytokines. The number of TLR2-positive macrophages increased in labyrinthine placenta. In fetal lung, intestine, liver, and brain there were modest changes in cytokine expressions. In fetal lung, SP and TLR mRNAs decreased and TLR2-positive macrophages redistributed around vessels. LPS-induced fetal deaths associated with early age (16 d gestation) rather than with proinflammatory activation. Here we propose that maternal LPS response leads to PTB and acute decrease of immune proteins in epithelial lining of fetal lung. Instead, acceleration of lung maturity has been previously observed in intraamniotic inflammation.

Epithelial cells of mucosal surfaces are critical for maintaining immune homeostasis by aiding in the discrimination of pathogenic and commensal microorganisms and modulating the activities of antigen-presenting cells and lymphocytes. Functional breakdowns resulting in chronic infection and inflammation are associated with the development of hematologic and solid neoplasms for which detailed pathogenetic mechanisms are poorly understood. Mice heterozygous for a transgene Col13a1 expressing a mutant collagen XIII developed clonal mature B-cell lineage lymphomas originating in mesenteric lymph nodes (MLN). The tumors were associated with T cells and macrophages. The incidence of disease was reduced 2-fold in transgenic mice raised under specific pathogen-free conditions, suggesting a role for infectious agents. The lymphomas did not express the mutant collagen XIII, indicating that its influence on tumorigenesis was B-cell extrinsic and likely to be associated with collagen XIII–positive tissues drained by the MLN. Studies of the small intestines of transgenic mice showed that the subepithelial basement membranes (BM) were highly abnormal and that they exhibited heightened expression of genes involved in immune responses. These results define collagen XIII–dependent maintenance of the intestinal BM as a previously unappreciated component of immune responses and a critical determinant of cancer susceptibility. [Cancer Res 2008;68(24):10324–32]

Overexpression of type XIII collagen molecules with an 83-amino-acid residue in-frame deletion of part of the ectodomain leads to fetal lethality in Col13a1(COL2del) transgenic mice. We characterize here the functional disturbances in the cardiovascular system of mouse fetuses overexpressing mutant type XIII collagen. Doppler ultrasonography was performed at 12.5 days of gestation on 33 fetuses resulting from heterozygous matings of seven female mice and on 16 fetuses from two matings between heterozygous and wild-type mice. Nine fetuses had atrioventricular valve regurgitation (AVVR), and all of them were transgene-positive. The fetuses with AVVR had a lower outflow mean velocity (V-mean; P < 0.005) and a greater proportion of isovolumetric relaxation time (IRT%) in the cardiac cycle (P < 0.0001) than those without AVVR, and their ductus venosus pulsatility indices for veins (DV PIV) and the umbilical artery pulsatility indices were increased. A positive correlation was found between IRT% and DV PIV, and a negative correlation was seen between outflow V-mean and DV PIV. Morphological analysis of the heart revealed no differences between the two groups of fetuses, but histological analysis showed the trabeculation of the ventricles to be reduced and the myocardium to be thinner in the fetuses with AVVR. Based on in situ hybridization, type XIII collagen mRNAs were normal constituents of these structures. Moreover, a positive correlation was found between outflow V-mean and myocardial thickness. IRT% and DV PIV correlated negatively with myocardial thickness. Thus, overexpression of mutant type XIII collagen results in mid-gestation cardiac dysfunction in mouse fetuses, and these disturbances in cardiac function may lead to death in utero.

AbstractEpithelial cells of mucosal surfaces are critical for maintaining immune homeostasis by aiding in the discrimination of pathogenic and commensal microorganisms and modulating the activities of antigen-presenting cells and lymphocytes. Functional breakdowns resulting in chronic infection and inflammation are associated with the development of hematologic and solid neoplasms for which detailed pathogenetic mechanisms are poorly understood. Mice heterozygous for a transgene Col13a1del expressing a mutant collagen XIII developed clonal mature B-cell lineage lymphomas originating in mesenteric lymph nodes (MLN). The tumors were associated with T cells and macrophages. The incidence of disease was reduced 2-fold in transgenic mice raised under specific pathogen-free conditions, suggesting a role for infectious agents. The lymphomas did not express the mutant collagen XIII, indicating that its influence on tumorigenesis was B-cell extrinsic and likely to be associated with collagen XIII–positive tissues drained by the MLN. Studies of the small intestines of transgenic mice showed that the subepithelial basement membranes (BM) were highly abnormal and that they exhibited heightened expression of genes involved in immune responses. These results define collagen XIII–dependent maintenance of the intestinal BM as a previously unappreciated component of immune responses and a critical determinant of cancer susceptibility. [Cancer Res 2008;68(24):10324–31]