Hypermethylation of FOXA1 and allelic loss of PTEN drive squamous differentiation and promote heterogeneity in bladder cancer

Intratumoral heterogeneity in bladder cancer is a barrier to accurate molecular sub-classification and treatment efficacy. However, individual cellular and mechanistic contributions to tumor heterogeneity are controversial. We examined potential mechanisms of FOXA1 and PTEN inactivation in bladder cancer and their contribution to tumor heterogeneity. These analyses were complemented with inactivation of FOXA1 and PTEN in intermediate and luminal mouse urothelium. We show inactivation and reduced expression of FOXA1 and PTEN is prevalent in human disease, where PTEN and FOXA1 are downregulated by allelic loss and site-specific DNA hypermethylation, respectively. Conditional inactivation of both Foxa1 and Pten in intermediate/luminal cells in mice results in development of bladder cancer exhibiting squamous features as well as enhanced sensitivity to a bladder-specific carcinogen. In addition, FOXA1 is hypermethylated in basal bladder cancer cell lines, and this is reversed by treatment with DNA methyltransferase inhibitors. By integrating human correlative and in vivo studies, we define a critical role for PTEN loss and epigenetic silencing of FOXA1 in heterogeneous human disease and show genetic targeting of luminal/intermediate cells in mice drives squamous differentiation.

Mitochondrial lipid droplet formation as a detoxification mechanism to sequester and degrade excessive urothelial membranes

The apical surface of the terminally differentiated mammalian urothelial umbrella cell is mechanically stable and highly impermeable, in part due to its coverage by urothelial plaques consisting of 2D crystals of uroplakin particles. The mechanism for regulating the uroplakin/plaque level is unclear. We found that genetic ablation of the highly tissue-specific sorting nexin Snx31, which localizes to plaques lining the multivesicular bodies (MVBs) in urothelial umbrella cells, abolishes MVBs suggesting that Snx31 plays a role in stabilizing the MVB-associated plaques by allowing them to achieve a greater curvature. Strikingly, Snx31 ablation also induces a massive accumulation of uroplakin-containing mitochondria-derived lipid droplets (LDs), which mediate uroplakin degradation via autophagy/lipophagy, leading to the loss of apical and fusiform vesicle plaques. These results suggest that MVBs play an active role in suppressing the excessive/wasteful endocytic degradation of uroplakins. Failure of this suppression mechanism triggers the formation of mitochondrial LDs so that excessive uroplakin membranes can be sequestered and degraded. Because mitochondrial LD formation, which occurs at a low level in normal urothelium, can also be induced by disturbance in uroplakin polymerization due to individual uroplakin knockout and by arsenite, a bladder carcinogen, this pathway may represent an inducible, versatile urothelial detoxification mechanism.

[Pathogenic gene variants and clinical phenotype features of 26 children with progressive myoclonic epilepsy]

Objective: To identify the pathogenic gene variants and clinical phenotype features of 26 children with progressive myoclonic epilepsy (PME). Methods: In this cross-sectional study, 26 PME children (11 boys and 15 girls) sent to neurological outpatient clinics and admitted to wards of the Department of Pediatrics, Peking University First Hospital were enrolled prospectively from January 2014 to October 2018. The pathogenic gene variants of PME children and their parents were identified by Sanger sequencing, next generation sequencing panels of epilepsy or trio-based whole exome sequencing and so on. The genotypes and phenotypes of the PME children were anaylzed. Results: The clinical features of 26 children include myoclonus, multiple types of seizures and progressive neurological regression. Their onset ages ranged from 3 months to 15 years. Several pathogenic gene variants were identified in the 15 patients, including TPP1 gene variantions in 3 patients; NEU1, GBA, TBC1D24 and KCNC1 gene variantions in 2 patients respectively; CLN6, MFSD8, ASAH1 and ATN1 gene variantions in 1 patient respectively. Several variants of uncertain significance were identified in 4 patients, including GOSR2 gene compound heterozygous variants in 2 patients, KCTD7 gene compound heterozygous variants in 1 patient, and compound heterozygous variants of an unreported TARS gene in 1 patient. No pathogenic gene variant was identified in 7 patients. In 15 children with the identified pathogenic gene variants, 5 patients were diagnosed with neuronal ceroid lipofuscinoses (NCL), 2 patients with sialidosis, 2 patients with neuronopathic Gaucher disease, 1 patient with dentatorubral-pallidoluysian atrophy (DRPLA), and 1 patient with spinal muscular atrophy-progressive myoclonic epilepsy (SMA-PME). Conclusions: PME include a group of diseases with genetic heterogeneity. Identification of the pathogenic gene variants of PME could help to predict the prognosis and guide the genetic counseling.

Characterization of Histone Deacetylase Expression Within In Vitro and In Vivo Bladder Cancer Model Systems

Epigenetic aberrations are prominent in bladder cancer (BC) and contribute to disease pathogenesis. We characterized histone deacetylase (HDAC) expression, a family of deacetylation enzymes, in both in vitro and in vivo BC model systems and analyzed expression data from The Cancer Genome Atlas (TCGA). Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting analysis was used to determine the expression status of Class I and II HDACs in ten human BC cell lines, while qRT-PCR was used to determine HDAC expression in 24 human tumor specimens. The TCGA cohort consists of 408 muscle invasive BC (MIBC) clinical samples and analysis of this data set identified expression of HDAC4 and -9 as being associated with basal–squamous disease. These findings agree with qRT-PCR results identifying increased expression of HDAC4, -7, and -9 in basal BC cell lines (p < 0.05; Kruskal–Wallis test) and in clinical specimens with invasive bladder cancer (not statistically significant). We also observed increased expression in Hdac4, -7, and -9 in commonly used BC mouse models. Here, we identify suitable preclinical model systems for the study of HDACs, and show increased expression of Class IIa HDACs, specifically HDAC4 and HDAC9, in basal BC cell lines and in invasive clinical specimens. These results suggest this class of HDACs may be best suited for targeted inhibition in patients with basal BC.

[Phenotype study of SCN2A gene related epilepsy]

Objective: To summarize the phenotype of epileptic children with SCN2A mutations. Methods: Epileptic patients who were treated in the Pediatric Department of Peking University First Hospital from September 2006 to October 2017 and detected with SCN2A mutations by targeted next-generation sequencing were enrolled. Clinical manifestations of all patients were analyzed retrospectively. Results: A total of 21 patients (16 boys and 5 girls) with SCN2A mutations were collected. Twenty-one SCN2A mutations were identified. Ten patients had mutations inherited from one of their parents and 11 patients had de novo mutations. The age of epilepsy onset was from 2 days to 2 years and 6 months: six patients with seizure onset in neonates (29%) , six patients with seizure onset between 1 month and 3 months of age (29%), three patients with seizure onset between 4 months and 6 months of age, two patients with seizure onset between 7 months and one year of age, and four patients with seizure onset beyond one year of age. Multiple seizure types were observed. The focal seizure was the most common seizure type which was observed in 18 patients (86%) . Spasm seizure was observed in 6 patients (29%) . Other seizure types were rare. In 19 patients, seizures manifested in clusters (90%) . In 3 patients, seizures manifested fever-sensitive. Nine of ten patients with inherited SCN2A mutations had normal development. However, all patients with de novo SCN2A mutations had mild or severer development delay. In 21 patients with SCN2A mutations, five were diagnosed with benign familial infantile epilepsy, 3 with benign familial neonatal-infantile epilepsy, 3 with Ohtahara syndrome, 3 with West syndrome, 2 with encephalopathy with early infantile onset epilepsy, one with febrile seizures plus, one with Dravet syndrome, one with encephalopathy with childhood-onset epilepsy, one with autism with epilepsy and one with intellectual disability with epilepsy. Conclusions: The clinical features of patients with SCN2A mutations include that main seizure onset is the neonate and early infancy, and the main seizure type is the focal seizure, manifested in clusters. The large spectrum of SCN2A-related epilepsy, which not only includes epilepsy with a comparatively favorable prognosis, but also epileptic encephalopathy. De novo mutations often lead to severe phenotype with development delay.

Uromodulin deficiency alters tubular injury and interstitial inflammation but not fibrosis in experimental obstructive nephropathy

Human GWAS and Mendelian genetic studies have linked polymorphic variants and mutations in the human uromodulin gene (UMOD) with chronic kidney disease. The primary function of this kidney‐specific and secreted protein remains elusive. This study investigated whether UMOD deficiency modified responses to unilateral ureteral obstruction (UUO)‐induced kidney injury. Kidneys harvested from groups of wild‐type (UMOD+/+) and knockout (UMOD−/−) male mice (n = 7–10 each) were studied on days 7, 14, and 21. Compared to sham kidneys, UMOD protein levels increased 9–13x after UUO and were associated with increased urinary UMOD levels. Kidney KIM‐1 protein levels were higher in the UMOD−/− groups at all time‐points (4–14x). The UMOD−/− groups also had higher KIM‐1 kidney‐to‐urine relative ratios (5–35x). In vitro studies using KIM‐1 expressing 769‐P cells showed lower KIM‐1 levels in the presence of UMOD protein. Levels of proapoptotic genes and the epithelial cell apoptotic protein marker M30 were significantly lower in the UMOD−/− groups. Both M30 and KIM‐1 colocalized with intraluminal UMOD protein deposits. Interstitial inflammation was less intense in the UMOD−/− groups. Renal fibrosis severity (kidney collagen mRNA and protein) was similar in both genotypic groups on days 7, 14, and 21. Our findings suggest a role for UMOD‐dependent inhibition of KIM‐1 expression and its apoptotic cell scavenging responses during chronic obstruction‐associated tubular injury.

The RING domain in the anti-apoptotic protein XIAP stabilizes c-Myc protein and preserves anchorage-independent growth of bladder cancer cells

X-linked inhibitor of apoptosis protein (XIAP) suppresses apoptosis and plays key roles in the development, growth, migration, and invasion of cancer cells. Therefore, XIAP has recently attracted much attention as a potential antineoplastic therapeutic target, requiring elucidation of the molecular mechanisms underlying its biological activities. Here, using shRNA-mediated gene silencing, immunoblotting, quantitative RT-PCR, anchorage-independent growth assay, and invasive assay, we found that XIAP's RING domain, but not its BIR domain, is crucial for XIAP-mediated up-regulation of c-Myc protein expression in human bladder cancer (BC) cells. Mechanistically, we observed that the RING domain stabilizes c-Myc by inhibiting its phosphorylation at Thr-58 and that this inhibition is due to activated ERK1/2-mediated phosphorylation of glycogen synthase kinase-3β (GSK-3β) at Ser-9. Functional studies further revealed that c-Myc protein promotes anchorage-independent growth and invasion stimulated by the XIAP RING domain in human BC cells. Collectively, the findings in our study uncover that the RING domain of XIAP supports c-Myc protein stability, providing insight into the molecular mechanism and role of c-Myc overexpression in cancer progression. Our observations support the notion of targeting XIAP's RING domain and c-Myc in cancer therapy.

MEG3, as a Competing Endogenous RNA, Binds with miR-27a to Promote PHLPP2 Protein Translation and Impairs Bladder Cancer Invasion

Muscle-invasive and metastatic bladder cancer have an extremely poor 5-year survival rate of 5%. In comparison, all other bladder cancers (BCs) have a 5-year survival rate of 77%. This striking contrast indicates that one of the therapeutic kernels for bladder cancer is to elucidate the molecular mechanisms underlying its invasiveness and metastasis. In the current study, we demonstrated that maternally expressed gene 3 (MEG3) is significantly downregulated in human invasive bladder cancers in comparison to non-invasive bladder cancers, and that ectopic expression of MEG3 dramatically inhibits the invasiveness of human bladder cancer cells. Consistently, ectopic expression of MEG3 also attenuates metastatic ability of T24T cells, a cell line derived from T24 cells, in the lungs of nude mice. Our mechanistic studies reveal that MEG3, as a ceRNA, inhibits the invasiveness of human bladder cancer cells via negative regulation of c-Myc by competing with PHLPP2 mRNA for miR-27a. These findings not only provide a novel insight into understanding the mechanisms behind the MEG3 inhibition of bladder cancer cell invasion, but also reveal the potential for use of MEG3 as a tool for the prevention and therapy of invasive bladder cancer.

Maintenance of the bladder cancer precursor urothelial hyperplasia requires FOXA1 and persistent expression of oncogenic HRAS

Tumorigenesis requires accumulation of genetic and epigenetic alterations, some of which drive tumor initiation. "Oncogene addiction" describes the phenomenon that (1) well-established cancers are dependent on one mutated oncogene or pathway for the maintenance of a malignant phenotype and that (2) withdrawal of the single oncogenic event leads to growth arrest and/or cancer regression. While oncogene addiction has been experimentally validated in advanced tumor models, its role in tumor precursors has not been investigated. We utilized the requirement of Forkhead box A1 (Foxa1) for transcriptional activation of the Upk2-promoter to temporally control the expression of Upk2-HRAS* oncogene, an inducer of urothelial hyperplasia in transgenic mice. Inducible homozygous knockout of Foxa1 in Upk2-HRAS*/UBC-CreERT2/Foxa1loxp/loxp mice results in reduced HRAS* levels. This led to a marked reduction of urothelial proliferation as evidenced by urothelial thinning, degenerative changes such as intracellular vacuole formation, and reduced Ki67 expression. Reduced proliferation did not affect basal, Krt14-positive cells, supporting the fact that Foxa1-regulated Upk2-HRAS* expression occurs primarily in supra-basal cells. Our results indicate that maintenance of urothelial hyperplasia in Upk2-HRAS* mice depends on continuous expression of Foxa1 and activated HRAS, and that mutated receptor tyrosine kinases, FOXA1 and/or other downstream effectors may mediate oncogene addiction in urothelial hyperplasia.

[Genotype-phenotype correlation in patients with alternating hemiplegia of childhood]

Objective: To explore the correlation between ATP1A3 genotype and phenotype in children with alternating hemiplegia of childhood (AHC). Methods: This was a retrospective study. The clinical data and peripheral blood DNA of AHC patients were collected in Peking University First Hospital from August 2005 to December 2017. ATP1A3 gene mutations were screened by Sanger sequencing or next generation sequencing (NGS). AHC patients were divided into difference groups according to different hotspot mutations. SPSS 23.0 was used to analyze the correlation between genotype and phenotype. Variance analysis was used to compare the measurement data between groups. Chi square test was used to compare the categorical data between groups. Kruskal-Wallis test was used to compare the unidirectional ordered data between groups. Least-significant difference(LSD) was used to compare the data between two groups. Results: A total of 119 AHC patients were recruited, including 68 males and 51 females. The onset age of 113 (95.0%) patients was within 18 months. There were 119 cases (100.0%) with hemiplegic seizures, 109 cases (91.6%) with abnormal eyeball movements, 104 cases (87.4%) with dystonia, 31 cases (26.1%) with autonomic neurological symptoms, 31 cases (26.1%) with epileptic seizures and 117 cases (98.3%) with long-term developmental delay. In 113 patients (95.0%) with ATP1A3 gene mutations, 111 were de novo mutation and 2 were genetic mutations. A total of 39 mutation types were found, including 37 missense mutations and 2 deletion mutations. Seventeen of them were novel mutations. The three hotspot mutations were D801N (n=34, 30.1%), E815K (n=20, 17.7%) and G947R (n=13, 11.5%). The age of onset of D801N and E815K were earlier than G947R ((3.1±2.1)and (2.3±2.3)vs.(6.4±7.7) months, P=0.004 and 0.003). The age of first hemiplegic events of D801N and E815K were earlier than G947R((6.4±3.1) and (6.8±3.3) vs. (11.4±10.1) months, P=0.004 and 0.016). More patients with E815K mutations presented epilepsy than those with D801N (P=0.003) and G947R (P=0.001). More patients with E815K mutations presented greater motor and intellectual disability than the patients with D801N (P=0.001) and G947R mutations (P=0.001). Conclusions: ATP1A3 gene is the main causative gene of AHC. Three hotspot mutations, D801N, E815K and G947R, were found. Hotspot mutation E815K is associated with the most severe phenotype, which presented an earlier age at the time of the first paroxysmal manifestation and first hemiplegic event, severer developmental delay and a greater proportion of epilepsy.

Uroplakins play conserved roles in egg fertilization and acquired additional urothelial functions during mammalian divergence

Uroplakin (UP) tetraspanins and their associated proteins are major mammalian urothelial differentiation products that form unique two-dimensional crystals of 16-nm particles (“urothelial plaques”) covering the apical urothelial surface. Although uroplakins are highly expressed only in mammalian urothelium and are often referred to as being urothelium specific, they are also expressed in several mouse nonurothelial cell types in stomach, kidney, prostate, epididymis, testis/sperms, and ovary/oocytes. In oocytes, uroplakins colocalize with CD9 on cell-surface and multivesicular body-derived exosomes, and the cytoplasmic tail of UPIIIa undergoes a conserved fertilization-dependent, Fyn-mediated tyrosine phosphorylation that also occurs in Xenopus laevis eggs. Uroplakin knockout and antibody blocking reduce mouse eggs’ fertilization rate in in vitro fertilization assays, and UPII/IIIa double-knockout mice have a smaller litter size. Phylogenetic analyses showed that uroplakin sequences underwent significant mammal-specific changes. These results suggest that, by mediating signal transduction and modulating membrane stability that do not require two-dimensional-crystal formation, uroplakins can perform conserved and more ancestral fertilization functions in mouse and frog eggs. Uroplakins acquired the ability to form two-dimensional-crystalline plaques during mammalian divergence, enabling them to perform additional functions, including umbrella cell enlargement and the formation of permeability and mechanical barriers, to protect/modify the apical surface of the modern-day mammalian urothelium.

[Targeting diagnosis and treatment value of chelating anti-IL-1β mAb-SPIONs in temporal lobe epilepsy model]

Objective: In order to study the diagnosis and treatment value of chelating anti-IL-1β mAb-SPIONs in temporal lobe epilepsy model induced by lithium chlorid and pilocarpine. Methods: Forty-five temporal lobe epilepsy model rats were randomly and equally divided into saline group, plain-SPIONs group, anti-IL-1β mAb-SPIONs group. Each group was injected with equal particles at day 3 and day 14 after the onset of seizures. MRI were conducteds before and 4 hours after particles injection and T₂ values were measured. The distribution of iron particles in the epileptic tissue was observed and the neuronal loss, astrocyte proliferation and microglia activation were detected. The expressions of IL-1β and NF-κBp65 in each group were detected meanwhile. Results: At day 14 after seizure, the value of T₂ was 84±14 after injecting anti-IL-1β mAb-SPIONs. Compared with the control group, the value of T₂ obviously declined. These phenomena of neuron loss, astrocyte proliferation and microglia activation had been improved obviously. IL-1βand NF-κBp65 expression also significantly reduced. Conclusion: Anti-IL-1β mAb-SPIONs can penetrate blood brain barrier and plays an important role in targeting positioning and targeting therapy in temporal lobe epilepsy.

[Clinical phenotypes of TBC1D24 gene related epilepsy]

Objective: To summarize the clinical features of TBC1D24 gene mutations associated with epilepsy. Methods: All the patients with TBC1D24 gene compound heterozygous mutations were retrospectively collected at the Pediatric Department of Peking University First Hospital from March 2015 to July 2017, and the features of clinical manifestations, electroencephalogram, and neuroimaging were analyzed. Results: Eighteen cases with TBC1D24 gene compound heterozygous mutations were included. The age of seizure onset was 1 day to 8 months, and the median age was 90 days. Seizure types included generalized tonic-clonic seizures (GTCS) in 3 cases, focal seizures in 18 cases, myoclonus in 18 cases, and 17 cases had focal myoclonus and myoclonus status. The focal myoclonus involving one or multiple muscle groups, sometimes migrating and alternating, lasting up to minutes to several days, and could be terminated by sleep or sedation drugs. In 11 cases, myoclonus was exacerbated by fever or infections, and 2 cases developed into myoclonic status during infection, in a severe case with the loss of consciousness. The magnetic resonance imaging (MRI) of seven patients was abnormal, including cerebral atrophy or cerebellar atrophy with abnormal signals. Segment myoclonus was captured in 10 patients, but without correlated epileptiform discharges. There were ten cases had varying degrees of developmental delay, 7 were normal, and one patient died of status epilepticus at the age of 4 months. Three cases had hearing disorders. In the 18 patients, the clinical phenotype of 4 cases consisted of epilepsy of infancy with migrating focal seizures, 2 with progressive myoclonus epilepsies, 1 with Dravet syndrome, 1 with DOORS syndrome, and 3 with unclassified epileptic encephalopathy. Conclusions: The clinical feature of TBC1D24 gene mutation related epilepsy was focal myoclonus, and tended to develop into myoclonic status epilepticus, and could be aggravated by infections, and terminated by sleep or sedation drugs. Mental retardation involved or not, neuroimaging could present with cerebral atrophy or cerebellar atrophy with abnormal signals.

Uromodulin regulates renal magnesium homeostasis through the ion channel transient receptor potential melastatin 6 (TRPM6)

Up to 15% of the population have mild to moderate chronic hypomagnesemia, which is associated with type 2 diabetes mellitus, hypertension, metabolic syndrome, and chronic kidney disease. The kidney is the key organ for magnesium homeostasis, but our understanding of renal magnesium regulation is very limited. Uromodulin (UMOD) is the most abundant urinary protein in humans, and here we report that UMOD has a role in renal magnesium homeostasis. Umod-knockout (Umod ^-/-) mice excreted more urinary magnesium than WT mice and displayed up-regulation of genes promoting magnesium absorption. The majority of magnesium is absorbed in the thick ascending limb. However, both mouse strains responded similarly to the diuretic agent furosemide, indicating appropriate function of the thick ascending limb in the Umod ^-/- mice. Magnesium absorption is fine-tuned in the distal convoluted tubule (DCT) via the apical magnesium channel transient receptor potential melastatin 6 (TRPM6). We observed decreased apical Trpm6 staining in the DCT of Umod ^-/- mice. Applying biotinylation assays and whole-cell patch-clamp recordings, we found that UMOD enhances TRPM6 cell-surface abundance and current density from the extracellular space. UMOD physically interacted with TRPM6 and thereby impaired dynamin-dependent TRPM6 endocytosis. WT mice fed a low-magnesium diet had an increased urinary UMOD secretion compared with the same mice on a regular diet. Our results suggest that increased urinary UMOD secretion in low-magnesium states reduces TRPM6 endocytosis and thereby up-regulates TRPM6 cell-surface abundance to defend against further urinary magnesium losses.

Aldehydes are the predominant forces inducing DNA damage and inhibiting DNA repair in tobacco smoke carcinogenesis

Tobacco smoke (TS) contains numerous cancer-causing agents, with polycyclic aromatic hydrocarbons (PAHs) and nitrosamines being most frequently cited as the major TS human cancer agents. Many lines of evidence seriously question this conclusion. To resolve this issue, we determined DNA adducts induced by the three major TS carcinogens: benzo(a)pyrene (BP), 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanoe (NNK), and aldehydes in humans and mice. In mice, TS induces abundant aldehyde-induced γ-hydroxy-propano-deoxyguanosine (γ-OH-PdG) and α-methyl-γ-OH-PdG adducts in the lung and bladder, but not in the heart and liver. TS does not induce the BP- and NNK-DNA adducts in lung, heart, liver, and bladder. TS also reduces DNA repair activity and the abundance of repair proteins, XPC and OGG1/2, in lung tissues. These TS effects were greatly reduced by diet with polyphenols. We found that γ-OH-PdG and α-methyl-γ-OH-PdG are the major adducts formed in tobacco smokers' buccal cells as well as the normal lung tissues of tobacco-smoking lung cancer patients, but not in lung tissues of nonsmokers. However, the levels of BP- and NNK-DNA adducts are the same in lung tissues of smokers and nonsmokers. We found that while BP and NNK can induce BPDE-dG and O6-methyl-dG adducts in human lung and bladder epithelial cells, these inductions can be inhibited by acrolein. Acrolein also can reduce DNA repair activity and repair proteins. We propose a TS carcinogenesis paradigm. Aldehydes are major TS carcinogens exerting dominant effect: Aldehydes induce mutagenic PdG adducts, impair DNA repair functions, and inhibit many procarcinogens in TS from becoming DNA-damaging agents.

PHLPP2 stabilization by p27 mediates its inhibition of bladder cancer invasion by promoting autophagic degradation of MMP2 protein

Pleckstrin homology domain leucine-rich repeat protein phosphatase 2 (PHLPP2) is a tumor suppressor that catalyzes the de-phosphorylation of the AGC kinases, while p27 acts as a tumor suppressor that regulates cell cycle, apoptosis, and cell motility. Our previous studies have identified that PHLPP2 participates in inhibition of transformation of human bronchial epithelial cells following lung carcinogen B[a]P/B[a]PDE exposure. However, nothing was known about the association of p27 with regulation of PHLPP2 expression and the role of PHLPP2 in bladder cancer (BC) invasion. In our current studies, we demonstrated that PHLPP2 inhibited BC invasion through promoting MMP2 degradation via p62-mediated autophagy; and p27 expression was able to stabilize PHLPP2 protein by inhibiting protein degradation of Hsp90, which could directly bind to PHLPP2 and protect it from degradation. More in-depth studies discovered that stabilization of Hsp90 by p27 was mediated by calpain1 proteolysis system, whereas p27 inhibited calpain1 gene transcription by attenuating Jak1/Stat1 cascade in human invasive BC cells. Collectively, we for the first time revealed PHLPP2 downregulation in BCs and its participating in promotion of BC invasion, as well as novel role of p27 and mechanisms underlying its regulation of PHLPP2 protein degradation through Hsp90-dependent manner. Our findings improve our understanding of p27 and PHLPP2 roles and their crosstalk in regulation of BC invasion, which further contributes to improve the current strategy for invasive bladder cancer therapy.

Uromodulin-SlpA binding dictates Lactobacillus acidophilus uptake by intestinal epithelial M cells

Bacterial access to the gut immune system is a crucial process to promote host immune responses. The probiotic L-92 strain of Lactobacillus acidophilus exerts anti-allergic immunomodulatory effects upon oral administration in mice. Here, we show that microfold cells (M cells) are responsible for L-92 internalization for evoking L-92-mediated immune responses. L-92 specifically bound to uromodulin, a glycosylphosphatidylinositol-anchored protein expressed exclusively on M cells among intestinal epithelial cells. Internalization of L-92 into M cells was significantly reduced in uromodulin-deficient (Umod-/-) mice compared to Umod+/+ mice. Furthermore, the binding of L-92 to uromodulin was significantly decreased after removal of surface layer protein A (SlpA) from the bacteria. Our study thus revealed a crucial role of uromodulin on the M-cell surface for the uptake of SlpA-positive lactic acid bacteria into M cells, possibly leading to subsequent delivery of the bacteria to dendritic cells closely associated with M cells for immunomodulation. Our study also shed light on the possibility that SlpA and uromodulin could be used as vehicle and target, respectively, for efficient mucosal vaccine delivery.

XIAP overexpression promotes bladder cancer invasion in vitro and lung metastasis in vivo via enhancing nucleolin-mediated Rho-GDIβ mRNA stability

Our recent studies demonstrate that X-linked inhibitor of apoptosis protein (XIAP) is essential for regulating colorectal cancer invasion. Here, we discovered that RhoGDIβ was a key XIAP downstream effector mediating bladder cancer (BC) invasion in vitro and in vivo. We found that both XIAP and RhoGDIβ expressions were consistently elevated in BCs of N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-treated mice in comparison to bladder tissues from vehicle-treated mice and human BCs in comparison to the paired adjacent normal bladder tissues. Knockdown of XIAP attenuated RhoGDIβ expression and reduced cancer cell invasion, whereas RhoGDIβ expression was attenuated in BBN-treated urothelium of RING-deletion knockin mice. Mechanistically, XIAP stabilized RhoGDIβ mRNA by its positively regulating nucleolin mRNA stability via Erks-dependent manner. Moreover, ectopic expression of GFP-RhoGDIβ in T24T(shXIAP) cells restored its lung metastasis in nude mice. Our results demonstrate that XIAP-regulated Erks/nucleolin/RhoGDIβ axis promoted BC invasion and lung metastasis.

[Spectrum of mutations in benign familial neonatal-infantile epilepsy]

Objective: To investigate the spectrum of mutations in families with benign familial neonatal-infantile epilepsy (BFNIE) . Methods: Clinical data and peripheral blood DNA samples of all BFNIE probands and their family members were collected from Peking University First Hospital between December 2012 and April 2016. Clinical phenotypes of affected members were analyzed. Genomic DNA was extracted from peripheral blood samples with standard protoco1. Mutations in PRRT2 were screened using Sanger sequencing. For families that PRRT2 mutations were not detected by Sanger sequencing, candidate gene mutations were further screened by next-generation sequencing for epilepsy. Results: A total of 7 families were collected. Of the 30 affected members, 15 were male and 15 were female. The age of epilepsy onset was from 2 days to 6 months. Genetic testing led to the identification of gene mutations in all families. One family had the PRRT2 hotspot mutation (c.649dupC). Three families had missense SCN2A mutations (c.2674G>A/p.V892I, c.2872A>G/p.M958V, and c.2627A>G/p.N876S) . Both c.2872A>G/p.M958V and c.2627A>G/p.N876S were novel SCN2A mutations. Three families had KCNQ2 mutations. Two of them had missense mutations (c.958G>A/p.V320I and c.998G>A/p.R333Q) . The KCNQ2 mutation c.958G>A/p.V320I was novel. One family had a gene deletion of KCNQ2, which also extended to the adjacent gene, CHRNA4; and the deletion involved all the exons of KCNQ2 and CHRNA4. Conclusions: Mutations in KCNQ2, SCN2A, and PRRT2 are genetic causes of BFNIE in Chinese families. The detection rate for gene mutations is high in BFNIE families. KCNQ2 and SCN2A mutations are common in BFNIE families. SCN2A mutations (c.2872A>G/p.M958V and c.2627A>G/p.N876S) and KCNQ2 mutation (c.958G>A/p.V320I) are novel mutations.

Novel transgenic knockout model of basal-squamous bladder cancer

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Background: The recent description of the highly aggressive Basal-Squamous molecular subtype of bladder cancer (BLCa) requires the development of new in vivo models for the study of this clinical entity. Although loss of the transcription factor Forkhead box A1 ( FOXA1) is significantly associated with the Basal-Squamous subtype, cooperating genetic alterations are unknown. Herein, we identify genetic alterations that potentially cooperate with FOXA1 loss to drive tumorigenesis and/or the Basal-Squamous phenotype and develop a novel transgenic model for the study of Basal-Squamous BLCa. Methods: We interrogated The Cancer Genome Atlas (TCGA) BLCa study to identify common genetic alterations associated with FOXA1 copy number (CN) loss. Based on our results, we utilized a bladder-specific Cre-LoxP ( Uroplakin II-Cre) to constitutively knock-out (KO) Foxa1 and/or Pten in mouse urothelium. Two cohorts of mice were aged for 6 and 12 months, and a third cohort was exposed to the bladder-specific carcinogen N-butyl-(4-hydroxybutyl)-nitrosamine (BBN; 0.05%) for 12 weeks. Following all experiments, the bladder tissue was isolated and characterized. Results: The TCGA data revealed that combined CN loss of both FOXA1 and PTEN occurs in 17% of MI BLCa patients. At 6 months of age, our mice developed urothelial hyperplasia, whereas at 12 months of age, double KO ( Foxa1-/-/Pten-/-) mice developed carcinoma in situ (CIS) with SqD, enriched for basal (Krt5/6 and 14) and reduced in luminal (Gata3 and Pparγ) markers. Increased tumor stage was significantly associated with combined KO of at least one allele of Foxa1 and Pten following BBN exposure. Moreover, upregulation of apoptosis related genes was observed by RNA-sequencing data. Conclusions: In advanced BLCa, CN loss of FOXA1 and PTEN is common. Genetic ablation of Foxa1 and Pten results in CIS with SqD and a pathologic profile consistent with the Basal-Squamous subtype and accelerated tumor onset following carcinogen exposure. Therefore, we describe the development of a novel model for the study of Basal-Squamous BLCa potentially useful for preclinical studies.

E-cigarette smoke damages DNA and reduces repair activity in mouse lung, heart, and bladder as well as in human lung and bladder cells

E-cigarette smoke delivers stimulant nicotine as aerosol without tobacco or the burning process. It contains neither carcinogenic incomplete combustion byproducts nor tobacco nitrosamines, the nicotine nitrosation products. E-cigarettes are promoted as safe and have gained significant popularity. In this study, instead of detecting nitrosamines, we directly measured DNA damage induced by nitrosamines in different organs of E-cigarette smoke-exposed mice. We found mutagenic O6-methyldeoxyguanosines and γ-hydroxy-1,N2 -propano-deoxyguanosines in the lung, bladder, and heart. DNA-repair activity and repair proteins XPC and OGG1/2 are significantly reduced in the lung. We found that nicotine and its metabolite, nicotine-derived nitrosamine ketone, can induce the same effects and enhance mutational susceptibility and tumorigenic transformation of cultured human bronchial epithelial and urothelial cells. These results indicate that nicotine nitrosation occurs in vivo in mice and that E-cigarette smoke is carcinogenic to the murine lung and bladder and harmful to the murine heart. It is therefore possible that E-cigarette smoke may contribute to lung and bladder cancer, as well as heart disease, in humans.

Tamm-Horsfall protein/uromodulin deficiency elicits tubular compensatory responses leading to hypertension and hyperuricemia

Expression of Tamm-Horsfall protein (THP or uromodulin) is highly restricted to the kidney thick ascending limb (TAL) of loop of Henle. Despite the unique location and recent association of THP gene mutations with hereditary uromodulin-associated kidney disease and THP single nucleotide polymorphisms with chronic kidney disease and hypertension, the physiological function(s) of THP and its pathological involvement remain incompletely understood. By studying age-dependent changes of THP knockout (KO) mice, we show here that young KO mice had significant salt and water wasting but were partially responsive to furosemide, due to decreased luminal translocation of Na-K-Cl cotransporter 2 (NKCC2) in the TAL. Aged THP KO mice were, however, markedly oliguric and unresponsive to furosemide, and their NKCC2 was localized primarily in the cytoplasm as evidenced by lipid raft floatation assay, cell fractionation, and confocal and immunoelectron microscopy. These aged KO mice responded to metolazone and acetazolamide, known to target distal and proximal tubules, respectively. They also had marked upregulation of renin in juxtaglomerular apparatus and serum, and they were hypertensive. Finally, the aged THP KO mice had significant upregulation of Na-coupled urate transporters Slc5a8 and Slc22a12 as well as sodium-hydrogen exchanger 3 (NHE3) in the proximal tubule and elevated serum uric acid and allantoin. Collectively, our results suggest that THP deficiency can cause progressive disturbances in renal functions via initially NKCC2 dysfunction and later compensatory responses, resulting in prolonged activation of the renin-angiotensin-aldosterone axis and hyperuricemia.

Tamm-Horsfall Protein Regulates Mononuclear Phagocytes in the Kidney

Tamm-Horsfall protein (THP), also known as uromodulin, is a kidney-specific protein produced by cells of the thick ascending limb of the loop of Henle. Although predominantly secreted apically into the urine, where it becomes highly polymerized, THP is also released basolaterally, toward the interstitium and circulation, to inhibit tubular inflammatory signaling. Whether, through this latter route, THP can also regulate the function of renal interstitial mononuclear phagocytes (MPCs) remains unclear, however. Here, we show that THP is primarily in a monomeric form in human serum. Compared with wild-type mice, THP^-/- mice had markedly fewer MPCs in the kidney. A nonpolymerizing, truncated form of THP stimulated the proliferation of human macrophage cells in culture and partially restored the number of kidney MPCs when administered to THP^-/- mice. Furthermore, resident renal MPCs had impaired phagocytic activity in the absence of THP. After ischemia-reperfusion injury, THP^-/- mice, compared with wild-type mice, exhibited aggravated injury and an impaired transition of renal macrophages toward an M2 healing phenotype. However, treatment of THP^-/- mice with truncated THP after ischemia-reperfusion injury mitigated the worsening of AKI. Taken together, our data suggest that interstitial THP positively regulates mononuclear phagocyte number, plasticity, and phagocytic activity. In addition to the effect of THP on the epithelium and granulopoiesis, this new immunomodulatory role could explain the protection conferred by THP during AKI.

Point mutation in D8C domain of Tamm-Horsfall protein/uromodulin in transgenic mice causes progressive renal damage and hyperuricemia

Hereditary mutations in Tamm-Horsfall protein (THP/uromodulin) gene cause autosomal dominant kidney diseases characterized by juvenile-onset hyperuricemia, gout and progressive kidney failure, although the disease pathogenesis remains unclear. Here we show that targeted expression in transgenic mice of a mutation within the domain of 8 cysteines of THP in kidneys' thick ascending limb (TAL) caused unfolded protein response in younger (1-month old) mice and apoptosis in older (12-month old) mice. While the young mice had urine concentration defects and polyuria, such defects progressively reversed in the older mice to marked oliguria, highly concentrated urine, fibrotic kidneys and reduced creatinine clearance. Both the young and the old transgenic mice had significantly higher serum uric acid and its catabolic product, allantoin, than age-matched wild-type mice. This THP mutation apparently caused primary defects in TAL by compromising the luminal translocation and reabsorptive functions of NKCC2 and ROMK and secondary responses in proximal tubules by upregulating NHE3 and URAT1. Our results strongly suggest that the progressive worsening of kidney functions reflects the accumulation of the deleterious effects of the misfolded mutant THP and the compensatory responses. Transgenic mice recapitulating human THP/uromodulin-associated kidney diseases could be used to elucidate their pathogenesis and test novel therapeutic strategies.

RhoGDIβ promotes Sp1/MMP-2 expression and bladder cancer invasion through perturbing miR-200c-targeted JNK2 protein translation

Our most recent studies demonstrate that RhoGDIβ is able to promote human bladder cancer (BC) invasion and metastasis in an X‐link inhibitor of apoptosis protein‐dependent fashion accompanied by increased levels of matrix metalloproteinase (MMP)‐2 protein expression. We also found that RhoGDIβ and MMP‐2 protein expressions are consistently upregulated in both invasive BC tissues and cell lines. In the present study, we show that knockdown of RhoGDIβ inhibited MMP‐2 protein expression accompanied by a reduction of invasion in human BC cells, whereas ectopic expression of RhoGDIβ upregulated MMP‐2 protein expression and promoted invasion as well. The mechanistic studies indicated that MMP‐2 was upregulated by RhoGDIβ at the transcriptional level by increased specific binding of the transcription factor Sp1 to the mmp‐2 promoter region. Further investigation revealed that RhoGDIβ overexpression led to downregulation of miR‐200c, whereas miR‐200c was able directly to target 3′‐UTR of jnk2mRNA and attenuated JNK2 protein translation, which resulted in attenuation of Sp1mRNA and protein expression in turn, inhibiting Sp1‐dependent mmp‐2 transcription. Collectively, our studies demonstrate that RhoGDIβ overexpression inhibits miR‐200c abundance, which consequently results in increases of JNK2 protein translation, Sp1 expression, mmp‐2 transcription, and BC invasion. These findings, together with our previous results showing X‐link inhibitor of apoptosis protein mediating mRNA stabilization of both RhoGDIβ and mmp‐2, reveal the nature of the MMP‐2 regulatory network, which leads to MMP‐2 overexpression and BC invasion.