Up-Regulation of Osteopontin, Chemokines, Adhesion Molecule, and Heat Shock Proteins in 1-Hour Biopsy From Cardiac Death Donor Kidneys

AIMS

Since April 1979, 471 kidneys were retrieved from donors after cardiac death (DCD) using an in situ regional cooling technique, with excellent renal function and good long-term graft survival. However, the precise cascade of events following transplantation of DCD kidneys and the influence of ischemia-reperfusion injury remain unclear. In this study, we performed gene expression profiling using 1-hour biopsy samples from DCD kidneys versus those from living sources.

METHODS

All kidney grafts were procured at our center using an in situ regional cooling technique from DCD. Living donor kidneys (LD) were harvested by open nephrectomy. All graft biopsies were performed 1 hour after reperfusion (DCD n = 8, LD n = 9). We analyzed the expression profile of 20,173 genes.

RESULTS

One hundred seventy eight genes were up-regulated (>2-fold difference and DCD/LD > 1.5) and 120 down-regulated (<1/2-fold and LD/DCD > 1.5) in DCD kidneys. Expression of osteopontin (22.5 +/- 2.6-fold DCD vs 7.7 +/- 1.7 LD; P < .001), chemokines (CCL4 4.4 +/- 0.7 vs 2.5 +/- 0.3; P < .01), (CCL2 6.0 +/- 1.3 vs 2.8 +/- 0.5), CXCL1 (9.5 +/- 0.4 vs 2.0 +/- 0.2), and CXCL2 (16.7 +/- 5.3 vs 4.8 +/- 1.3; P < .05), adhesion molecule (ICAM-1 4.7 +/- 0.7 vs 2.5 +/- 0.4; P < .05), and heat shock proteins (HSPA1L 6.7 +/- 0.7 vs 1.6 +/- 0.3, HSPA1A 17.7 +/- 2.6 vs 2.4 +/- 0.5, HSPA1B 13.3 +/- 0.2 vs 3.0 +/- 0.7, HSPA5 6.7 +/- 0.8 vs 3.2 +/- 0.3, HSPB1 2.9 +/- 0.2 vs 1.0 +/- 0.1, and HSPH1 19.4 +/- 3.0 vs 5.9 +/- 1.1; P < .001) were up-regulated in the kidneys from DCD.

CONCLUSION

This report analyzed global gene expression using 1-hour biopsy samples from DCD kidneys. These results may provide new insight into the identification of novel target genes for the development of therapeutic approaches and for determining graft viability of kidneys from DCD.

CDH1 is a specific marker for undifferentiated spermatogonia in mouse testes

In the mammalian testis, spermatogenesis is initiated from a subset of stem cells belonging to undifferentiated type A spermatogonia. In spite of the biologic significance of undifferentiated type A spermatogonia, little is known about their behavior and properties because of a lack of specific cell surface markers. Here we show that CDH1 (previously known as E-cadherin) is expressed specifically in undifferentiated type A spermatogonia in the mouse testis. Histologic analysis showed that CDH1-positive cells had all the characteristics of undifferentiated type A spermatogonia. Whole-mount immunohistochemistry showed that CDH1-positive cells made clusters mainly comprising one, two, four, or eight cells. They survived after administration of the cytotoxic agent busulfan to mice, and then regenerated seminiferous epithelia. Transplantation experiments showed that only CDH1-positive cells had colonizing activity in the recipient testis. Our data clearly demonstrated that spermatogenic stem cells reside among undifferentiated type A spermatogonia, which express CDH1.

Meiotic recombination and spatial proximity in the etiology of the recurrent t(11;22)

Although balanced translocations are among the most common human chromosomal aberrations, the constitutional t(11;22)(q23;q11) is the only known recurrent non-Robertsonian translocation. Evidence indicates that de novo formation of the t(11;22) occurs during meiosis. To test the hypothesis that spatial proximity of chromosomes 11 and 22 in meiotic prophase oocytes and spermatocytes plays a role in the rearrangement, the positions of the 11q23 and 22q11 translocation breakpoints were examined. Fluorescence in situ hybridization with use of DNA probes for these sites demonstrates that 11q23 is closer to 22q11 in meiosis than to a control at 6q26. Although chromosome 21p11, another control, often lies as close to 11q23 as does 22q11 during meiosis, chromosome 21 rarely rearranges with 11q23, and the DNA sequence of chromosome 21 appears to be less susceptible than 22q11 to double-strand breaks (DSBs). It has been suggested that the rearrangement recurs as a result of the palindromic AT-rich repeats at both 11q23 and 22q11, which extrude hairpin structures that are susceptible to DSBs. To determine whether the DSBs at these sites coincide with normal hotspots of meiotic recombination, immunocytochemical mapping of MLH1, a protein involved in crossing over, was employed. The results indicate that the translocation breakpoints do not coincide with recombination hotspots and therefore are unlikely to be the result of meiotic programmed DSBs, although MRE11 is likely to be involved. Previous analysis indicated that the DSBs appear to be repaired by a mechanism similar to nonhomologous end joining (NHEJ), although NHEJ is normally suppressed during meiosis. Taken together, these studies support the hypothesis that physical proximity between 11q23 and 22q11--but not typical meiotic recombinational activity in meiotic prophase--plays an important role in the generation of the constitutional t(11;22) rearrangement.

The mildest form of acute necrotizing encephalopathy associated with influenza A

We experienced the mildest form of acute necrotizing encephalopathy associated with influenza A. A previously healthy 13-year-old girl had mildly decreased consciousness and delirious behavior lasting for a week. Diffusion-weighted imaging showed mildly high signal intensities in the bilateral thalami, deep white matter in the centrum semiovale, and frontal lobes. Conventional T (1)- or T (2)-weighted images revealed no abnormalities.

Microarray analysis of differentially expressed fetal genes in placental tissue derived from early and late onset severe pre-eclampsia

Although it has been well documented that pre-eclampsia is caused by a combination of maternal and fetal susceptibility genes, little is known about the precise etiology of this complicated disorder. To investigate how the expression of fetal genes contributes to the mechanisms underlying the progression of this disease, we have analyzed differentially expressed genes using placentas from 13 normal pregnancies and 14 pregnancies with severe pre-eclampsia. We performed genome-wide expression profiling using high-density oligonucleotide microarrays, followed by validation using real-time PCR. Among the 47,000 genes that were screened in the microarray, 137 genes were found to be differentially expressed between normal and pre-eclamptic tissues. Among these candidates, 70 were up-regulated and 67 were down-regulated. The up-regulated genes included leptin and inhibin A, which are well-known biological markers for pre-eclampsia, as well as FLT1, which was recently proved to be tightly linked with the etiology of this disease. Gene ontology analysis further revealed several biological processes that could be associated with the development of pre-eclampsia, including response to stress, host-pathogen interactions, lipid metabolism, and carbohydrate metabolism. Analyses of biological mechanisms highlighted some important pathways that may be involved in this disorder, such as the TGF-beta and CEBPA-related pathways. Furthermore, when our present subjects were classified as either severe cases of early onset or late onset pre-eclampsia, the expression of 11 genes could be correlated with the severity of this disorder. These genes may therefore prove to be novel biological markers by which the severity of this condition could be predicted. Our data are likely to be a useful future resource in the elucidation of the disease-process and in the identification of novel markers for pre-eclampsia.

Palindrome-mediated chromosomal translocations in humans

Recently, it has emerged that palindrome-mediated genomic instability contributes to a diverse group of genomic rearrangements including translocations, deletions, and amplifications. One of the best studied examples is the recurrent t(11;22) constitutional translocation in humans that has been well documented to be mediated by palindromic AT-rich repeats (PATRRs) on chromosomes 11q23 and 22q11. De novo examples of the translocation are detected at a high frequency in sperm samples from normal healthy males, but not in lymphoblasts or fibroblasts. Cloned breakpoint sequences preferentially form a cruciform configuration in vitro. Analysis of the junction fragments implicates frequent double-strand-breaks (DSBs) at the center of both palindromic regions, followed by repair through the non-homologous end joining (NHEJ) pathway. We propose that the PATRR adopts a cruciform structure in male meiotic cells, creating genomic instability that leads to the recurrent translocation.

Analysis of gene-expression profiles by oligonucleotide microarray in children with influenza

In order to clarify the mechanism of the host response to influenza virus, gene-expression profiles of peripheral blood obtained from paediatric patients with influenza were investigated by oligonucleotide microarray. In the acute phase of influenza, 200 genes were upregulated and 20 genes were downregulated compared with their expression in the convalescent phase. Interferon-regulated genes, such as interferon-induced protein with tetratricopeptide repeats 2 (IFIT2) and vipirin, were strongly upregulated in the acute phase. Gene ontology analysis showed that immune response genes were highly overrepresented among the upregulated genes. Gene-expression profiles of influenza patients with and without febrile convulsion were also studied. In patients with febrile convulsion, 22 genes were upregulated and five were downregulated compared with their expression in patients without febrile convulsion. These results should help to clarify the pathogenesis of influenza and its neurological complications.

Increased water intake decreases progression of polycystic kidney disease in the PCK rat

Renal enlargement in polycystic kidney disease (PKD) is caused by the proliferation of mural epithelial cells and transepithelial fluid secretion into the cavities of innumerable cysts. Arginine vasopressin (AVP) stimulates the proliferation of human PKD cells in vitro via cAMP-dependent activation of the B-Raf/MEK (MAPK/ERK kinase/extracellular signal-regulated kinase (ERK) pathway. ERK activity is elevated in cells that line the cysts in animals with PKD, and AVP receptor antagonists reduce ERK activity and halt disease progression. For suppression of the effect of AVP physiologically, water intake was increased in PCK rats, a model of PKD, and the effect on renal morphology, cellular mechanism, and function was determined. The addition of 5% glucose in the drinking water increased fluid intake approximately 3.5-fold compared with rats that received tap water. In PCK rats, increased water intake for 10 wk reduced urinary AVP excretion (68.3%), and urine osmolality fell below 290 mOsmol/kg. High water intake was associated with reduced renal expression of AVP V2 receptors (41.0%), B-Raf (15.4%), phosphorylated ERK (38.1%), and proliferating cell nuclear antigen-positive renal cells (61.7%). High water intake reduced the kidney/body weight ratio 28.0% and improved renal function. Taken together, these data demonstrate that water intake that is sufficient to cause persistent water diuresis suppresses B-Raf/MEK/ERK activity and decreases cyst and renal volumes in PCK rats. It is suggested that limiting serum AVP levels by increased water intake may be beneficial to some patients with PKD.

Chromosomal translocations mediated by palindromic DNA

There is evidence accumulating to suggest that non-B DNA structures have a potential for genomic instability that induces genomic rearrangements including translocations and deletions. One of the best studied examples is the recurrent t(11;22) constitutional translocation in humans that is mediated by palindromic AT-rich repeats (PATRRs) on chromosomes 11q23 and 22q11. Cloned breakpoint sequences favor adopting a cruciform configuration in vitro. Analysis of the junction fragments implicates frequent double-strand-breaks at the center of both palindromic regions, followed by repair through the nonhomologous end joining pathway. De novo examples of the translocation are detected at a substantial frequency in sperm samples from normal healthy males, but not in other normal somatic tissues or cell lines derived from humans. Further our recent findings indicate that polymorphism of the PATRR affects the frequency of de novo translocation events and symmetrical alleles preferentially generate the translocation. We propose that the symmetric PATRR is likely to adopt a cruciform structure in male meiotic cells, creating genomic instability that leads to the recurrent translocation.

Expression analysis of a mouse orthologue of HSFY, a candidate for the azoospermic factor on the human Y chromosome

Heat shock transcription factor on Y (HSFY) is located in one of three candidate regions for azoospermic factor (AZF), AZFb on the Y chromosome. We and others have already revealed that some azoospermic males are missing the regions of the Y chromosome including HSFY. Previously, we showed that murine HSFY-like sequence [mHSFYL (Riken cDNA 4933413G11Rik)], which is the mouse orthologue of HSFY, is exclusively expressed in testis. The sequences encoding the presumed DNA-binding domain in HSFY and mHSFYL were found in other mammals such as dogs, cows and chickens. To elucidate mHSFYL expression in the testes in detail, we carried out in situ hybridization. mHSFYL was predominantly expressed in round spermatids. Furthermore, we clarified the intracellular distribution of mHSFYL in COS1 cells with HA- or GFP-tagged proteins. Both HA-mHSFYL and GFP-mHSFYL were located in the nucleus. Our results suggest that HSFY/mHSFYL may have evolutionarily conserved functions for spermatogenesis.

Expression profiling of muscles from Fukuyama-type congenital muscular dystrophy and laminin-α2 deficient congenital muscular dystrophy; is congenital muscular dystrophy a primary fibrotic disease?

Fukuyama-type congenital muscular dystrophy (FCMD) and laminin-alpha2 deficient congenital muscular dystrophy (MDC1A) are congenital muscular dystrophies (CMDs) and they both are categorized into the same clinical entity of muscular dystrophy as Duchenne muscular dystrophy (DMD). All three disorders share a common etiologic defect in the dystrophin-glycoprotein complex, which connects muscle structural proteins with the extracellular basement membrane. To investigate the pathophysiology of these CMDs, we generated microarray gene expression profiles of skeletal muscle from patients in various clinical stages. Despite diverse pathological changes, the correlation coefficient of overall gene expression among these samples was considerably high. We performed a multi-dimensional statistical analysis, the Distillation, to extract determinant genes that distinguish CMD muscle from normal controls. Up-regulated genes were primarily extracellular matrix (ECM) components, whereas down-regulated genes included structural components of mature muscle. These observations reflect active interstitial fibrosis with less active regeneration of muscle cell components in the CMDs, characteristics that are clearly distinct from those of DMD. Although the severity of fibrosis varied among the specimens tested, ECM gene expression was consistently high without substantial changes through the clinical course. Further, in situ hybridization showed more prominent ECM gene expression on muscle cells than on interstitial tissue cells, suggesting that ECM components are induced by regeneration process rather than by 'dystrophy.' These data imply that the etiology of FCMD and MDC1A differs from that of the chronic phase of classical muscular dystrophy, and the major pathophysiologic change in CMDs might instead result from primary active fibrosis.

Aberrant neuromuscular junctions and delayed terminal muscle fiber maturation in alpha-dystroglycanopathies

Recent studies have revealed an association between post-translational modification of alpha-dystroglycan (alpha-DG) and certain congenital muscular dystrophies known as secondary alpha-dystroglycanopathies (alpha-DGpathies). Fukuyama-type congenital muscular dystrophy (FCMD) is classified as a secondary alpha-DGpathy because the responsible gene, fukutin, is a putative glycosyltransferase for alpha-DG. To investigate the pathophysiology of secondary alpha-DGpathies, we profiled gene expression in skeletal muscle from FCMD patients. cDNA microarray analysis and quantitative real-time polymerase chain reaction showed that expression of developmentally regulated genes, including myosin heavy chain (MYH) and myogenic transcription factors (MRF4, myogenin and MyoD), in FCMD muscle fibers is inconsistent with dystrophy and active muscle regeneration, instead more of implicating maturational arrest. FCMD skeletal muscle contained mainly immature type 2C fibers positive for immature-type MYH. These characteristics are distinct from Duchenne muscular dystrophy, suggesting that another mechanism in addition to dystrophy accounts for the FCMD skeletal muscle lesion. Immunohistochemical analysis revealed morphologically aberrant neuromuscular junctions (NMJs) lacking MRF4 co-localization. Hypoglycosylated alpha-DG indicated a lack of aggregation, and acetylcholine receptor (AChR) clustering was compromised in FCMD and the myodystrophy mouse, another model of secondary alpha-DGpathy. Electron microscopy showed aberrant NMJs and neural terminals, as well as myotubes with maturational defects. Functional analysis of NMJs of alpha-DGpathy showed decreased miniature endplate potential and higher sensitivities to d-Tubocurarine, suggesting aberrant or collapsed formation of NMJs. Because alpha-DG aggregation and subsequent clustering of AChR are crucial for NMJ formation, hypoglycosylation of alpha-DG results in aberrant NMJ formation and delayed muscle terminal maturation in secondary alpha-DGpathies. Although severe necrotic degeneration or wasting of skeletal muscle fibers is the main cause of congenital muscular dystrophies, maturational delay of muscle fibers also underlies the etiology of secondary alpha-DGpathies.

Genetic variation affects de novo translocation frequency

Translocation is one of the most frequently occurring human chromosomal aberrations. The constitutional t(11;22)(q23;q11), which is the only known recurrent non-Robertsonian translocation, represents a good model for studying translocations in humans. Here we demonstrate polymorphisms of the palindromic sequence at the t(11;22) breakpoint that affect the frequency of de novo translocations in sperm from normal males. A typical allele consists of a perfect palindrome, producing ~10-5 de novo t(11;22) translocations. Alleles with an asymmetric center do not form the t(11;22). Our data show the importance of genome sequence on chromosomal rearrangements, a class of human mutation that is thought to be random.

Differential expression of caveolin-3 in mouse smooth muscle cells in vivo

Expression of caveolin-1 and -3 in mouse smooth muscle cells in vivo was examined by immunohistochemistry. Caveolin-1 was detected in almost all smooth muscles examined, except for the pupillary dilator muscle, whereas caveolin-3 was present only in smooth muscles of some specific tissues. In the eye, the pupillary sphincter muscle was intensely positive for caveolin-3, whereas the ciliary muscle and pupillary dilator muscle were negative. In the gastrointestinal tract, caveolin-3 was detected in the inner circular layer, but not in the outer longitudinal layer. Vascular smooth muscle cells of the resistance-sized artery in the uterus and corpus cavernosum were intensely positive for caveolin-3, whereas those of the aorta were only weakly positive and those of the vena cava were negative. Caveolin-3 was also detected in smooth muscle cells of the urinary bladder, ureter, prostatic vas deferens, and seminal vesicle. The different levels of caveolin-3 expression among various smooth muscle tissues were confirmed by Western blot analysis. Even within the same muscle, the relative expression levels of caveolin-1 and -3 were variable among neighboring cells, suggesting distinct fine regulation of expression of these two caveolins. Moreover, even in the same cell, caveolin-1 and -3 showed different distributions. These results indicate that the two caveolins form distinct caveolae in smooth muscles, and that caveolin-1 and -3 serve different functions. Their differential expression may therefore be related to the functional diversity of smooth muscles.

Genomic rearrangement at 10q24 in non-syndromic split-hand/split-foot malformation

Split-hand/split-foot malformation (SHFM) is a congenital limb malformation characterized by a median cleft of hand and/or foot due to the absence of central rays. Five loci for syndromic and non-syndromic SHFM, termed SHFM1-5, have been mapped to date. Recently, a 0.5 Mb tandem genomic duplication was found at chromosome 10q24 in SHFM3 families. To refine the minimum duplicated region and to further characterize the SHFM3 locus, we screened 28 non-syndromic SHFM families for tandem genomic duplication of 10q24 by Southern blot and sequence analysis of the dactylin gene. Of 28 families, only two showed genomic rearrangements. Representative patients from the two families exhibit typical SHFM, with symmetrically affected hands and feet. One patient is a familial case with a 511,661 bp tandem duplication, whereas the second is a sporadic case arising from a de novo, 447,338 bp duplication of maternal origin. The smaller duplication in the second patient contained the LBX1, BTRC, POLL, and DPCD genes and a disrupted extra copy of the dactylin gene, and was nearly identical to the smallest known duplicated region of SHFM3. Our results indicate that genomic rearrangement of SHFM3 is rare among non-syndromic SHFM patients and emphasize the importance of screening for genomic rearrangements even in sporadic cases of SHFM.

Fukutin and alpha-dystroglycanopathies

Fukuyama-type congenital muscular dystrophy (FCMD), Walker-Warburg syndrome (WWS), and muscle-eye-brain (MEB) disease are clinically similar autosomal recessive disorders characterized by congenital muscular dystrophy, lissencephaly, and eye anomalies. We identified the gene for FCMD and MEB, which encodes the fukutin protein and the protein O-linked mannose beta1, 2-N-acetylglucosaminyltransferase (POMGnT1), respectively. Recent studies have revealed that posttranslational modification of alpha-dystroglycan is associated with these congenital muscular dystrophies with brain malformations. All are characterized by hypoglycosylated alpha-dystroglycan. Fukutin's function and the relation with other alpha-dystroglycanopathies are discussed.

Palindromic AT-rich repeat in the NF1 gene is hypervariable in humans and evolutionarily conserved in primates

Palindromic sequences are dispersed in the human genome and may cause chromosomal translocations in humans. They constitute unsequenced gaps in the human genome because of their resistance to PCR amplification, cloning into vectors, and sequencing. We have overcome these difficulties by using a combination of optimized PCR conditions, cloning in a recombination-deficient E. coli strain, and RNA polymerases in sequencing. Using these methods, we analyzed a palindromic AT-rich repeat (PATRR) in the neurofibromatosis type 1 (NF1) gene on chromosome 17 (17PATRR). The 17PATRR manifests a size polymorphism due to a highly variable length of (AT)(n) dinucleotide repeats within the PATRR. 17PATRRs can be categorized into two types: a longer one that comprises a nearly or completely perfect palindrome, and a shorter one that represents its deleted asymmetric derivative. In vitro analysis shows that the longer 17PATRR is more likely to form a cruciform structure than the shorter one. Two reported t(17;22)(q11;q11) patients with NF1, whose breakpoints were identified within the 17PATRR, have translocations that are derived from perfect or nearly perfect palindromic alleles. This implies that the symmetric structure of a PATRR can induce a translocation. We identified conserved PATRRs within the NF1 gene in great apes and similar inverted repeats in two Old World monkeys, but not in New World monkeys or other mammals. This indicates that the palindromic region appeared approximately 25 million years ago and elongated during primate evolution. Although such palindromic regions are usually unstable and disappear rapidly due to deletion, the 17PATRR in the NF1 gene was stably conserved during evolution for reasons that are still unknown.

Basement membrane fragility underlies embryonic lethality in fukutin-null mice

Fukuyama-type congenital muscular dystrophy (FCMD), associated with brain malformation due to defects in neuronal migration, is caused by mutations in fukutin. Several lines of evidence suggest that the fukutin protein plays a pivotal role in synthesis of O-mannosyl sugar moieties of alpha-dystroglycan, a cell surface laminin receptor. Here, through targeted disruption of the orthologous mouse fukutin gene, we show that the fukutin protein is essential, as homozygous-null embryos die by E9.5 of gestation. Fukutin-null embryos show phenotypic diversity, features of which include growth retardation, folding of the egg cylinder, leakage of maternal red blood cells into the yolk sac cavity, and an increased number of apoptotic cells in the ectoderm. Loss of immunoreactivity against sugar moieties in alpha-dystroglycan suggests a reduced laminin-binding capacity. Ultrastructural analysis shows thin and breached basement membranes (BMs). BM fragility may underlie all of these abnormal phenotypes, and maintenance of BM function may require fukutin-mediated glycosylation of alpha-dystroglycan early in embryonic development.

Androgen Receptor Pathway in Rats with Autosomal Dominant Polycystic Kidney Disease

Androgens have been implicated in mediating disease escalation in autosomal dominant polycystic kidney disease (ADPKD). Dihydrotestosterone (DHT), an agonist, and flutamide (FLT), an antagonist, were administered to Han:SPRD rats with ADPKD, and the role of androgen receptor (AR) abundance and activation on the enlargement and function of cystic kidneys was evaluated. Renal AR abundance determined by immunoblots in 8- to 10-wk-old Cy/+ male rats was naturally increased four-fold above that of littermate +/+ controls. In male Cy/+, castration decreased AR abundance below control +/+ by -89.4%, and AR expression within cyst mural epithelial cells was strikingly decreased. Castration of Cy/+ male rats also reduced the usual increases in kidney weight by -49.7%, kidney cyst area by -34.0%, and serum urea nitrogen by -72.8%; these indices were restored to precastration levels by DHT. In Cy/+ male rats, FLT administration reduced the increase in kidney weight by -27.6% and serum urea nitrogen by -53.7% and decreased the increment in AR expression by -84.2% in comparison with untreated +/+ controls. There was no effect of FLT in female rats. Immunoblot expression of phospho-extracellular signal-regulated kinase 1/2 (P-ERK) and B-Raf, key intermediates in the mitogen-activated protein kinase pathway that are abnormally elevated in Cy/+, was unaffected by castration and/or administration of DHT or FLT. AR was not expressed in renal epithelial cell nuclei of androgen-deficient rats but was displayed in most tubule and mural cyst cell nuclei of androgen-replete rats. In androgen-deficient Cy/+, 80.6% of renal epithelial cells that had entered the cell cycle (proliferating cell nuclear antigen positive) also expressed P-ERK. In androgen-replete rats, proliferating cell nuclear antigen-positive cells co-expressed AR (12.7%), P-ERK (36.4%), and P-ERK + AR (45.0%); 5.9% were probably stimulated by other mitogenic mechanisms. It is concluded that androgens potentiate renal cell proliferation and cyst enlargement through ERK1/2-dependent and ERK1/2-independent signaling mechanisms in Han:SPRD. It is suggested that the basal rate of cell proliferation is determined by ERK1/2 signaling to a major extent and that androgens have additive effects.

Gene expression profile in rat renal isografts from brain dead donors

BACKGROUND

Brain death (BD) and the subsequent ischemia/reperfusion (I/R) injury have cardinal implications for the pathogenesis of kidney transplantation (Tx). However, the precise mechanistic pathway of BD and the subsequent I/R injury are unknown. In this study, we performed genome-wide analysis for differential gene expression in kidney isografts from BD donors. Their gene expressions were compared with those from living sources.

METHODS

Kidneys from BD rats were engrafted and their gene expressions were compared with those from living controls. Donors were intubated, and mechanically ventilated for 6 hours. Grafts were harvested 6 hours after BD, and 1 hour after engraftment. The expression profile of approximately 20,500 genes was analyzed.

RESULTS

Gene expression of chemokines (Scya2 and Gro1), cytokines (IL-1 and -6) and adhesion molecules (E- and P-selectin and ICAM-1) were upregulated in the BD kidneys and 1 hour after engraftment. An antiapoptotic gene (Birc2), IkappaB-zeta, and protective gene (HO-1) were also upregulated. Other upregulated genes included oncogenes (lipocalin2, Bcl3, and CCAAT/enhancer binding protein delta), Calgranulin B, DEXRAS1, insulin-like growth factor binding protein-1, inhibin beta-B-subunit gene, IgG Fc receptor, and FK 506 binding protein 5. We also observed downregulation of the genes Amphiphsin, Jagged 1, Pace 4, Slc15a2, Kcnn2, and gap junction membrane channel protein alpha5 only in kidneys from BD donors.

CONCLUSIONS

This is the first demonstration of global gene expression analysis using the rat brain-death isograft model. These results provide new insights for the detection of novel target genes for treatment and prognosis of grafts from brain-dead and extended marginal donors.

Human herpesvirus 6 (HHV-6) is transmitted from parent to child in an integrated form and characterization of cases with chromosomally integrated HHV-6 DNA

We obtained 7,566 peripheral blood mononuclear cell (PBMC) samples from 2,332 individuals and screened them for human herpesvirus infection. We identified five individuals who persistently harbored high copy numbers of human herpesvirus 6 (HHV-6) DNA in their PBMCs. HHV-6 DNA was also detected in other somatic tissues of these individuals. Five additional cases were identified among their family members. For two of these families, chromosomally integrated HHV-6 DNA (CIHHV-6) was detected in the PBMCs by fluorescence in situ hybridization. The prevalence of CIHHV-6 among all the subjects was 0.21%. The HHV-6 DNA was variant B in four families and variant A in one family. Antibodies to immediate early antigen and glycoprotein B were detected in 57 and 14% of individuals with CIHHV-6 and in 0 and 60% of healthy volunteers without CIHHV-6, respectively. HHV-6 could not be isolated from PBMCs with CIHHV-6. These cases shared no clinical features, and included three healthy individuals. Our data suggest that CIHHV-6 is rare but detectable in the general population and that hereditary transmission is one of the routes of HHV-6 transmission.

Cruciform DNA structure underlies the etiology for palindrome-mediated human chromosomal translocations

There is accumulating evidence to suggest that palindromic AT-rich repeats (PATRRs) represent hot spots of double-strand breakage that lead to recurrent chromosomal translocations in humans. As a mechanism for such rearrangements, we proposed that the PATRR forms a cruciform structure that is the source of genomic instability. To test this hypothesis, we have investigated the tertiary structure of a cloned PATRR. We have observed that a plasmid containing this PATRR undergoes a conformational change, causing temperature-dependent mobility changes upon agarose gel electrophoresis. The mobility shift is observed in physiologic salt concentrations and is most prominent when the plasmid DNA is incubated at room temperature prior to electrophoresis. Analysis using two-dimensional gel electrophoresis indicates that the mobility shift results from the formation of a cruciform structure. S1 nuclease and T7 endonuclease both cut the plasmid into a linear form, also suggesting cruciform formation. Furthermore, anti-cruciform DNA antibody reduces the electrophoretic mobility of the PATRR-containing fragment. Finally, we have directly visualized cruciform extrusions from the plasmid DNA with the size expected of hairpin arms using atomic force microscopy. Our data imply that for human chromosomes, translocation susceptibility is mediated by PATRRs and likely results from their unstable conformation.