Consensus statements on the management of clinically localized prostate cancer from the Hong Kong Urological Association and the Hong Kong Society of Uro-Oncology.

OBJECTIVE: To formulate consensus statements to facilitate physician management strategies for patients with clinically localized prostate cancer (PCa) in Hong Kong by jointly convening a panel of 12 experts from the two local professional organizations representing PCa specialists, who had previously established consensus statements on the management of metastatic PCa for the locality. METHODS: Through a series of meetings, the panellists discussed their clinical experience and the published evidence regarding various areas of the management of localized PCa, then drafted consensus statements. At the final meeting, each drafted statement was voted on by every panellist based on its practicability of recommendation in the locality. RESULTS: A total of 76 consensus statements were ultimately accepted and established by panel voting. CONCLUSION: Derived from the recent evidence and major overseas guidelines, along with local clinical experience and practicability, the consensus statements were aimed to serve as a practical reference for physicians in Hong Kong for the management of localized PCa.

Consensus statements on the management of metastatic prostate cancer from the Hong Kong Urological Association and Hong Kong Society of Uro-Oncology.

To establish a set of consensus statements to facilitate physician management strategies for patients with metastatic prostate cancer (mPCa) in Hong Kong. A local expert consensus was organized jointly by the two main professional organizations representing prostate cancer specialists in Hong Kong. A total of 12 experts were included in the consensus panel. Six of the most crucial and relevant areas of debate regarding the management of mPCa were identified. With the use of a modified Delphi method, several panel meetings were held for the members to discuss their clinical experience and the published literature relevant to the areas of debate. At the final meeting, each drafted statement was voted on by every member based on its practicability of recommendation in the locality. After the panel voting, a total of 45 consensus statements regarding the management of mPCa were ultimately accepted and established. The consensus statements were primarily derived from the latest clinical evidence and major overseas guidelines, with the consideration of local clinical experience and practicability. These are considered applicable recommendations for Hong Kong physicians for the management of mPCa patients.

Dietary consumption and diet diversity and risk of developing bladder cancer: results from the South and East China case-control study.

BACKGROUND: The epidemiologic evidence on the role of dietary consumption on the risk of bladder cancer in the Chinese population is limited. We investigated the role of dietary consumption and diet diversity on the risk of developing bladder cancer within a Chinese population. METHODS: A case-control study of 487 cases and 469 controls was conducted in four hospitals in China. A food frequency questionnaire was used to gather information on the consumption of 35 food items. Unconditional logistic regression models were used to derive odds ratios (ORs) and corresponding 95 % confidence intervals (95 % CI) for the relationship between dietary factors, dietary diversity scores, and bladder cancer. RESULTS: The ORs of bladder cancer for red meat (OR = 1.8, 95 % CI:1.1-3.0;p(trend) = 0.01), organ meat (OR = 1.6, 95 % CI:0.9-2.9;p(trend) = 0.04), leafy vegetables (OR = 2.9, 95 % CI:1.6-5.4;p trend = 0.003), bulb vegetables (OR = 2.3, 95 % CI:1.3-4.0;p(trend) = 0.003), and preserved vegetables (OR = 2.3, 95 % CI:1.2-4.2;p(trend) = 0.02) were significantly increased when comparing the highest to lowest level of consumption. The ORs for white fresh fish (OR = 0.5, 95 % CI:0.3-0.9;p(trend) = 0.004), citrus fruits (OR = 0.4, 95 % CI:0.3-0.8;p(trend) = 0.007), stone fruits (OR = 0.4, 95 % CI:0.2-0.6;p(trend) < 0.001), vine fruits (OR = 0.5, 95 % CI:0.2-1.0;p(trend) = 0.02), flower vegetables (OR = 0.3, 95 % CI:0.2-0.6;p(trend) < 0.001), potatoes (OR = 0.4, 95 % CI:0.2-0.9;p(trend) = 0.005), or dairy products (OR = 0.4, 95 % CI:0.3-0.7;p(trend) < 0.001) were significantly decreased when comparing the highest to lowest level of consumption. Subjects with the highest total diet diversity (OR = 0.4, 95 % CI:0.2-1.1;p(trend) = 0.02) and fruit diversity (OR = 0.1, 95 % CI:0.0-0.3;p(trend) < 0.001) had reduced ORs of and compared to subjects with the lowest diversity. CONCLUSION: Our results indicate that a diet with higher total diet diversity and in particular fruit diversity may reduce the risk of bladder cancer.

Prostate cancer management in the era of COVID-19: Recommendations from the Hong Kong Urological Association and Hong Kong Society of Uro-oncology.

AIM: In response to the fast-developing coronavirus disease 2019 (COVID-19) pandemic, special arrangement and coordination are urgently required in the interdisciplinary care of patients across different medical specialties. This article provides recommendations on the management of different stages of localized or metastatic prostate cancer (PC) amid this pandemic. METHODS: The Hong Kong Urological Association and Hong Kong Society of Uro-oncology formed a joint discussion panel, which consisted of six urologists and six clinical oncologists with extensive experience in the public and private sectors. Following an evidence-based approach, the latest relevant publications were searched and reviewed, before proceeding to a structured discussion of relevant clinical issues. RESULTS: The joint panel provided recommendations for PC management during the pandemic, in terms of general considerations, diagnostic procedures, different disease stages, treatment modules, patient support, and interdisciplinary collaboration. The overall goal was to minimize the risk of infection while avoiding unnecessary delays and compromises in management outcomes. Practical issues during the pandemic were addressed such as the use of invasive diagnostic procedures, robotic-assisted laparoscopic prostatectomy, hypofractionated radiotherapy, and prolonged androgen deprivation therapy. The recommendations were explicated in the context of Hong Kong, a highly populated international city, in relation to the latest international guidelines and evidence. CONCLUSION: A range of recommendations on the management of PC patients during the COVID-19 pandemic was developed. Urologists, oncologists, and physicians treating PC patients may refer to them as practical guidance.

Hong Kong Urological Association-Hong Kong Society of Uro-Oncology consensus statements on the management of advanced prostate cancer-2019 Updates.

BACKGROUND: To update the Hong Kong Urological Association-Hong Kong Society of Uro-Oncology consensus statements on the management of advanced prostate cancer, the same panelists as in the previous consensus panel held a series of meetings to discuss updated clinical evidence and experiences. METHODS: The previous consensus statements were retained, deleted, or revised, and new statements were added. At the final meeting, all statements were reviewed and amended as appropriate, followed by panel voting. RESULTS: There were significant changes and additions to the previous consensus statements, primarily driven by the advances in androgen receptor signaling inhibitors, treatment sequencing in metastatic castration-resistant prostate cancer, and increasing recognition of oligometastatic prostate cancer since the introduction of prostate-specific membrane antigen positron emission tomography. In this update, a total of 59 consensus statements were accepted and established. CONCLUSIONS: The consensus panel updated consensus statements on the management of advanced prostate cancer, aiming to allow physicians in the region to keep abreast of the recent evidence on optimal clinical practices.

Fluid intake and the risk of bladder cancer: results from the South and East China case-control study on bladder cancer.

Although several studies have assessed the association between total fluid intake, specific drinks and bladder cancer, no firm conclusions can yet be drawn. Four hundred thirty two bladder cancer cases and 392 frequency matched hospital-based controls recruited in the South and East of China between October 2005 and June 2008 were interviewed on their intake of 6 nonalcoholic and 3 alcoholic drinks. Age, sex, smoking and hospital-adjusted odds ratios (OR) and 95 percent confidence intervals (95% CI) were calculated for all drinks and for total fluid intake using logistic regression. For 381 cases (81.9% men) and 371 controls (76.3% men), total fluid intake could be calculated. In men, an increase in total fluid intake was associated with a significantly decreased bladder cancer risk (OR 0.93, 95% CI: 0.88-0.99, per cup fluid consumed). Neither green nor black tea consumption was associated with bladder cancer. Daily consumption of milk significantly reduced the risk of bladder cancer by a half (OR 0.49, 95% CI: 0.32-0.76), which strengthens earlier suggestions that milk is probably associated with a decreased bladder cancer risk. Consumption of wine (OR 0.49, 95% CI: 0.34-0.70) and liquor/spirits (OR 0.65, 95% CI: 0.47-0.92) were associated with a significantly reduced risk. Consumption of water, fruit juice and beer appeared not associated with bladder cancer. There is no clear indication that the risks observed in this Chinese population are substantially different from those observed in Caucasian populations.

CT angiography versus conventional digital angiography in preoperative assessment for Chinese living kidney donors.

BACKGROUND: Computed tomography (CT) angiography is used for preoperative evaluation of living kidney donors, but its correlation with intraoperative findings during the transplant operation remains unknown. METHODS: Between April 1997 and October 2008, 34 consecutive pairs of living kidney transplants were carried out. Conventional digital angiography was employed for the preoperative assessment in the first 19 pairs, and CT angiography in the subsequent 15 pairs. The radiological reports and operative findings during kidney harvest were carefully examined and compared. RESULTS: Among the 34 cases in our cohort, we found 9 early branching renal arteries (26.4%) and 6 double renal arteries (17%). Venous and ureteral anomalies were rare, with only 1 case (2.9%) of each. CT angiography offered excellent and equal accuracy (accuracy 100%) when compared with conventional digital angiography for renal arterial anatomy. CT angiography showed superior performance compared with conventional angiography in the domain of venous and collecting system anomalies (accuracy 100% vs. 94.7%, respectively). No contrast nephropathy or allergy was documented in our series. CONCLUSIONS: CT angiography showed excellent correlations with surgical findings in the Chinese population. It is associated with minimal risk of contrast nephropathy as well as lower cost and therefore should be adopted as the standard preoperative assessment of living kidney donors.

Characterization of an acrosome protein VAD1.2/AEP2 which is differentially expressed in spermatogenesis.

The release of enzymes from the acrosome of the sperm head (acrosome reaction) starts the fertilization process and enables the spermatozoa to penetrate the zona pellucida of the oocytes. Defective acrosome reaction is one of the important causes of infertility in men. To investigate the molecular regulation of spermatogenesis in vivo, we used differential display reverse transcription-polymerase chain reaction to identify stage-specific genes in a retinol-supplemented vitamin-A deficiency (VAD) rat model and identified the VAD1.2 (acrosome-expressed protein 2, AEP2) gene, which was expressed strongly in the rat testis from post-natal day 32 to adult stage. The mouse VAD1.2 mRNA shared 85% and 67% sequence homology, and 74% and 38% amino acid homology, respectively, with the rat and human counterparts. VAD1.2 transcript was abundantly expressed in the rat seminiferous tubules at stage VIII-XII, and the protein was detected in the acrosome region of the round and elongated spermatids of mouse, human, monkey and pig. VAD1.2 co-localized with lectin-PNA to the acrosome region of spermatids. Interestingly, the expression of VAD1.2 protein in human testis diminished in patients with hypospermatogenesis, maturation arrest, undescended testis and Sertoli cell-only syndrome. Co-immunoprecipitation experiments followed by western blotting and mass spectrometry (MS-MS) identified syntaxin 1, beta-actin and myosin heavy chain (MHC) proteins as putative interacting partners. Taken together, the stage-specific expression of VAD1.2 in the acrosome of spermatids and the binding of VAD1.2 protein with vesicle forming (syntaxin 1) and structural (beta-actin and MHC) proteins suggest that VAD1.2 maybe involved in acrosome formation during spermiogenesis.

Electrophoretic separation and characterization of urinary glycosaminoglycans and their roles in urolithiasis.

Urinary polyanions recovered from the urine samples of kidney stone-formers and normal controls were subjected to preparative agarose gel electrophoresis, which yielded fractions 1-5 in a decreasing order of mobility. In both groups, chondroitin sulfates were identified in the fast-moving fractions and heparan sulfates in the slow-moving fractions. Furthermore, two types of heparan sulfates were identified based on their electrophoretic mobility: slow-moving and fast-moving. The fractionated urinary polyanions were then tested in an in vitro calcium oxalate crystallization assay and compared at the same uronic acid concentration, whereby, the chondroitin sulfates of stone-formers and heparan sulfates of normals enhanced crystal nucleation. Fraction 5 of the normals, containing glycoproteins (14-97 kDa) and associated glycosaminoglycans, were found to effectively inhibit crystallization. Papainization of this fraction in stone-formers revealed crystal-suppressive effects of glycoproteins, which was not seen in similar fractions of normals. It was concluded that glycoproteins could modulate the crystal-enhancing glycosaminoglycans such as chondroitin sulfates of stone-formers but not in normals. The differing crystallization activities of electrophoretic fraction 1 of normals and stone-formers revealed the presence of another class of glycosaminoglycan-hyaluronan. Hence, in the natural milieu, different macromolecules combine to have an overall outcome in the crystallization of calcium oxalate.

Physical activity and risk of prostate and bladder cancer in China: The South and East China case-control study on prostate and bladder cancer.

BACKGROUND: Recent meta-analyses have suggested a modest protective effect of high levels of physical activity on developing both prostate and bladder cancer, but significant heterogeneity between studies included in these meta-analyses existed. To our knowledge, few Chinese studies investigated the association between physical activity and prostate cancer and none between physical activity and bladder cancer. Given the inconsistencies between previous studies and because studies on the relation between physical activity and prostate and bladder cancer in China are scarce, it remains elusive whether there is a relationship between physical activity and prostate and bladder cancer within the Chinese population. METHODS: We investigated the association between physical activity and risk of developing prostate and bladder cancer within a hospital-based case-control study in the East and South of China among 260 and 438 incident prostate and bladder cancer cases, respectively, and 427 controls. A questionnaire was administered to measure physical activity as metabolic equivalents (METs). Random effects logistic regression was used to calculate odds ratios (ORs) of prostate and bladder cancer for different levels of physical activity and for the specific activities of walking and cycling. RESULTS: Increasing overall physical activity was associated with a significant reduction in prostate cancer risk (Ptrend = 0.04) with the highest activity tertile level showing a nearly 50% reduction in prostate cancer risk (OR = 0.53, 95%CI: 0.28-0.98). Overall physical activity was not significantly associated with risk of bladder cancer (Ptrend = 0.61), neither were vigorous (Ptrend = 0.60) or moderate levels of physical activity (Ptrend = 0.21). Walking and cycling were not significantly associated with either prostate (Ptrend> = 0.62) or bladder cancer risk (Ptrend> = 0.25). CONCLUSIONS: The findings of this largest ever case-control study in China investigating the relationship between physical activity and prostate and bladder cancer suggest that overall physical activity is associated with a decreased risk of prostate cancer, but not with bladder cancer.

Kidney claudin-19: localization in distal tubules and collecting ducts and dysregulation in polycystic renal disease.

Tight junction (TJ) constitutes the barrier by controlling the passage of ions and molecules via paracellular pathway and the movement of proteins and lipids between apical and basolateral domains of the plasma membrane. Claudins, occludin, and junctional adhesion molecules are the major three transmembrane proteins at TJ. This study focuses a newly identified mammalian TJ gene, claudin-19, in kidneys. Mouse claudin-19 composes of 224 amino acids and shares 98.2% and 95% amino acid homology with rat and human, respectively; the most evolutionary-related claudins are claudin-1 and -7, which share approximately 75% DNA sequence homology with claudin-19. Claudin-19 is abundantly expressed in the mouse and rat kidneys among the organs examined by Northern blots, and to a much less extent, also found in brain by RT-PCR. Claudin-19 and zonula occludens-1 (ZO-1) are localized at junctional regions of Madin-Darby canine kidney (MDCK) cells by immunofluorescent microscopy. In addition, ZO-1 is found in the claudin-19-associated protein complexes in MDCK cells by co-immunoprecipitation. Using aquaporin-1 and aquaporin-2 antibodies as markers for different renal segment, strong expression of claudin-19 was observed in distal tubules of the cortex as well as in the collecting ducts of the medulla. To less extent, claudin-19 is also present in the proximal tubules (cortex) and in the loop of Henle (medulla). Furthermore, intense claudin-19 immunoreactivity is found co-localized with the ZO-1 in kidneys from postnatal day 15, day 45, and adult rats and mice. Similar localizations of claudin-19 and ZO-1 are also observed in human kidneys. Since these renal segments are mainly for controlling the paracellular cation transport, it is suggested that claudin-19 may participate in these processes. In human polycystic kidneys, decreased expression and dyslocalization of claudin-19 are noticed, suggesting a possible correlation between claudin-19 and renal disorders. Taken together, claudin-19 is a claudin isoform that is highly and specifically expressed in renal tubules with a putative role in TJ homeostasis in renal physiology.

Sp1 site is crucial for the mouse claudin-19 gene expression in the kidney cells.

Members of the claudin family play important roles in the formation of tight junctions in the kidneys, liver and intestine. Claudin-19 (Cldn19), a newly identified member of this family, is highly expressed in the kidney of the mouse. To have a better understanding on mouse claudin-19 gene expression, a 0.9-kb DNA fragment containing the 5'-flanking region of the Cldn19 gene was isolated. DNA sequence comparison between the mouse and human Cldn19 promoter regions exhibited little homology. One transcription initiation site was located at 104 nucleotides upstream of the start codon (ATG) of the Cldn19 gene. The mouse claudin-19 promoter lacked typical CAAT or GC-box. Deletion constructs of the 0.9-kb DNA fragment were generated and fused to a promoterless luciferase (Luc) reporter plasmid. Transfection studies using various kidney cell lines (MDCK, mIMCD3 and HEK293) revealed that the minimal promoter fragment resided in the -39 to -108 region, which contained a number of binding sites for transcription factors including Sp1. Site-directed mutagenesis using specific oligo probes confirmed that Sp1 was crucial for Cldn19 transactivation in the three cell lines studied. Electromobility shift assay confirmed that the nuclear extracts of these cells bound to the Sp1 oligo derived from Cldn19 promoter, but not to the mutated Sp1 oligo probe. Moreover, this DNA-protein complex would be recognized by Sp1 antibody, indicating specific Sp1 binding. Collectively, our data suggest that Sp1 binds to the claudin-19 promoter region and is responsible for its expression in the kidney cell lines in vitro.

The role of nuclear matrix protein 22 combined with bladder tumor antigen stat test in surveillance of recurring bladder cancer.

OBJECTIVE: To investigate a non-invasive, effective and rapid mode of detecting the recurrence of bladder cancer during follow-up. METHODS: Ninety patients following transurethral resection of bladder tumor (TURBt) surgery were recruited from January 1998 to March 2000. Standard ELISA was used to determine the quantity of nuclear matrix protein (NMP-22) in urine of all bladder cancer patients during their follow-up periods. Urine bladder tumor antigen (BTA) stat test was simultaneously performed and followed by cystoscopy. RESULTS: The total positive rates of urinary NMP-22 and BTA stat test were 76.7% (33/43) and 67.4% (29/43), respectively. Comparatively, this positive rate would increase to 93.0% (40/43) when the combination of both urine NMP-22 and BTA test were adopted. CONCLUSION: Examination of NMP-22 in urine is a rapid and effective way to detect the recurrence of bladder cancer. If combined with BTA test, NMP-22 may be used as a non-invasive method in surveillance of recurring of bladder cancer, which may reduce the frequency of patients needing to undergo conventional invasive cystoscopy.

Pyeloduodenocolic fistula.

A 75-year-old man presented with epigastric pain and melaena. Multiple right renal stones were seen on abdominal X-ray. Computed tomography of the abdomen and oesophagogastroduodenoscopy revealed features of a pyeloduodenal fistula. Elective surgery was planned but the patient developed torrential bleeding with shock. Emergency laparotomy revealed a necrotic right kidney with a pyeloduodenocolic fistula. This report is the first of a pyeloduodenocolic fistula caused by squamous cell carcinoma of the renal pelvis. We review the literature and discuss the aetiologies, clinical presentations, diagnosis, and treatment of pyeloduodenal fistula.

Robot-assisted radical prostatectomy in Hong Kong: a review of 235 cases.

OBJECTIVES: To report the outcome of all robot-assisted laparoscopic radical prostatectomy (RALP) in the public health care system in Hong Kong. PATIENTS AND METHODS: All patients who underwent RALP in the public health care system with at least 1 year of follow-up were evaluated. Data analysis included age, body mass index, preoperative prostate-specific antigen (PSA) level, D'Amico risk category, operative details, pathologic stage, follow-up continence, potency, and biochemical recurrence. RESULTS: Between 2005 and 2009, 235 patients underwent RALP, with a mean age of 66.4±5.9 years and a mean preoperative PSA level of 11.0±10.5 ng/mL. Complications were 16 (7%) in total. There were 176 (74.9%) patients with pT(2) disease and 55 (23.4%) patients with pT(3) disease. The overall rate of positive surgical margins (PSM) was 20.7%. At postoperative 12 months, 72.5% of the patients were pad free. For those 83 preoperative potent patients having nerve-sparing surgery, the overall trifecta rate at 12 months was 37.3%. Multivariate analysis identified that pathologic T staging was significantly associated with PSM, with an odds ratio (OR) of 7.884 (95% confidence interval [CI]: 3.576-17.379; P<0.001) for the pT(3) group compared with the pT(2) group. When comparing D'Amico medium- and high-risk categories with low-risk categories, they were found to be significantly associated with biochemical failure (medium- compared with low-risk: OR=3.536, 95% CI: 1.253-10.173, P=0.016; high- compared with low-risk: OR=10.214, 95% CI: 2.958-35.274, P<0.001). CONCLUSIONS: Our data demonstrate the feasibility, safety, and efficacy of RALP in low-to-intermediate volume centers. Our early oncologic outcomes were significantly correlated with pathologic stage and D'Amico risk stratification.

The initial and subsequent inflammatory events during calcium oxalate lithiasis.

BACKGROUND: Crystallization is believed to be the initiation step of urolithiasis, even though it is unknown where inside the nephron the first crystal nucleation occurs. METHODS: Direct nucleation of calcium oxalate and subsequent events including crystal retention, cellular damage, endocytosis, and hyaluronan (HA) expression, were tested in a two-compartment culture system with intact human proximal tubular HK-2 cell monolayer. RESULTS: Calcium oxalate dihydrate (COD) was nucleated and bound onto the apical surface of the HK-2 cells under hypercalciuric and hyperoxaluric conditions. These cells displayed mild cellular damage and internalized some of the adhered crystals within 18h post-COD-exposure, as revealed by electron microscopy. Prolonged incubation in complete medium caused significant damage to disrupt the monolayer integrity. Furthermore, hyaluronan disaccharides were detected in the harvested media, and were associated with HAS-3 mRNA expression. CONCLUSION: Human proximal cells were able to internalize COD crystals which nucleated directly onto the apical surface, subsequently triggering cellular damage and HAS-3 specific hyaluronan synthesis as an inflammatory response. The proximal tubule cells here demonstrate that it plays an important role in facilitating urolithiasis via endocytosis and creating an inflammatory environment whereby free hyaluronan in tubular fluid can act as crystal-binding molecule at the later segments of distal and collecting tubules.

Blockage of testicular connexins induced apoptosis in rat seminiferous epithelium.

Spermatogenesis, a tightly regulated developmental process of male germ cells in testis, is associated with temporal and spatial expression of gap junction proteins, such as the connexin family members. Perturbation of their expressions may lead to spermatogenic arrest as manifested by disruption of cell-cell interaction. To explore the role(s) of connexins during spermatogenesis, we utilized the small peptide antagonistic approach to specifically deplete connexin 31, connexin 33, and pan-connexin. Three connexin peptides corresponding to the extracellular binding domain of connexin 31 and connexin 33 and to the extracellular conserved domain of connexins were designed and synthesized commercially. Peptides (at single dosage of 0.5, 1, or 2 mg per animal) were injected into rat testes and testes were collected on day 0, 1, 3, 5, 10, 15, and 30 after microinjection. In situ TUNEL assay demonstrated the induction of apoptosis in the testes after pan-connexin peptide treatment in a dose-dependent manner from day 3 and onward. Unlike the pan-connexin peptide, connexin 31 and connexin 33 peptides appeared to have little effect on inducing apoptosis and germ cell loss. CD45 staining also detected the occasional presence of infiltrating lymphocytes in the seminiferous tubules. Accompanied with the apoptotic events, two apoptotic markers, NF-kappaB and caspase 3, demonstrated a general up-regulation in their expressions. In adjacent testis sections, eliminations of connexin 31, 32, and 43 were observed. However, an induction of connexin 33 expression was detected. This suggests the versatility and functional diversity of connexins in the testis. The expression of ZO-1, the only known adaptor of connexins in the testis, was reduced and remained in a low level in the seminiferous epithelium. As such, the alterations of connexins in seminiferous epithelium may induce apoptotic signaling in the testis via the caspase 3 and the NF-kappaB pathway. This demonstrates the significant role of testicular connexins to maintain the survival of germ cells by regulating inter-cellular communications among germ cells and adjacent supporting cells during spermatogenesis. In addition, the inter-relationship between connexins and other junction proteins and associated signaling protein were investigated. After pan-connexin peptide treatment, a dys-localization of N-cadherin, an adherens junction protein, and diminution of occludin, a tight junction protein, level were detected. In addition, inductions of junction regulatory protein, cathepsin L, was observed during the course of peptide-mediated germ cell loss in the testes. In summary, pan-connexin peptide treatment triggered apoptosis and germ cell loss in the testes. This event influenced the localization and expression of different junction proteins and junction-associated protein in the testes.

Acrosome-specific gene AEP1: identification, characterization and roles in spermatogenesis.

Spermatogenesis is a tightly regulated process leading to the development of spermatozoa. To elucidate the molecular spermatogenic mechanisms, we identified an acrosome-specific gene AEP1 in spermatids, which is located in rat chromosome 17p14 with a transcript size of 3,091 bp encoding a signal peptide, zinc finger-like motif, coiled-coil region, several predicted glycosylation and phosphorylation sites. Northern blot and RT-PCR analyses revealed the restricted expression of AEP1 to the testis only. In postnatal rat testes, AEP1 mRNA became detectable from postnatal 25 dpp (round spermatids) and onwards. By using in situ hybridization (ISH) and flow cytometry-fluorescent ISH, only the haploid spermatids yielded the positive AEP1 signal. Immunohistochemistry showed that AEP1 was expressed in the acrosomal cap of late-staged germ cells in rat testis, and co-localized with the acrosomal marker, peanut agglutinin. The spatial expression of AEP1 immunoreactivity in testis was conserved among diverse mammalian species (rat, pig, monkey, human). To further study its roles in spermatogenesis, we showed AEP1 and beta-actin was associated together in complex by co-immunoprecipitation in adult germ cells and by immunofluorescence assay in isolated spermatozoon. In human testes diagnosed with hypospermatogenesis, lower expression of AEP1 was observed, whereas there was no detectable signal in undescended testes. In short, AEP1 is an evolutionary-conserved acrosome-specific gene and likely functions in acrosome-cap formation.

VCY2 protein interacts with the HECT domain of ubiquitin-protein ligase E3A.

VCY2 locates in the AZFc region on chromosome Yq and is frequently deleted in infertile men with severe oligozoospermia or azoospermia. VCY2 is a testis-specific protein with unknown function. This study was to identify the protein that interacts with VCY2. We used the full-length VCY2 as bait to screen the human testis cDNA library using yeast two-hybrid approach. We identified a number of positive-interacting clones that encode ubiquitin-protein ligase E3A (UBE3A). UBE3A contains a HECT domain that binds VCY2. The specificity of the interaction was confirmed by co-immunoprecipitation and yeast mating. Northern blot analyses revealed two UBE3A transcripts 1.4 and 2kb that were abundantly expressed in human testis. We also showed that both VCY2 and UBE3A mRNAs were expressed in ejaculated human spermatozoa, indicating that both genes localize in the germ cell compartment. These data suggest that UBE3A ubiquitination may be required for VCY2 function.