Use of the anterior prostatic urethral mucosa preservation technique during holmium laser enucleation of the prostate can reduce postoperative stress urinary incontinence.

INTRODUCTION: Holmium laser enucleation of the prostate (HoLEP) is an effective and safe surgery for patients with benign prostatic hyperplasia. However, some patients exhibit postoperative urinary incontinence. Here, we compared surgical outcomes and incidence of stress urinary incontinence between HoLEP with and without anterior prostatic urethral mucosa preservation (APUMP). METHODS: All patients in this study underwent HoLEP with APUMP technique (APUMP group) and without APUMP technique (no-APUMP group). Enucleation weight, enucleation time, max flow rate increase at 3 months, and urinary incontinence rates immediately after catheter removal and at 1 month after surgery were compared between the groups. RESULTS: In the APUMP (n = 340) and no-APUMP (n = 75) groups, the median enucleation weights were 34.5 and 35.0 g, respectively (p = .982). The corresponding median enucleation times were 33.0 and 46.5 min (p < .01), and median max flow rate increases at 1 month were 10.5 and 9.9 mL/s (p = .89). The urinary incontinence rates immediately after catheter removal were 4.1% and 14.7% (p < .01), and were 3.8% and 12.0% (p < .01) at 1 month after surgery. CONCLUSION: HoLEP using the APUMP technique could be performed with a shorter operative time while maintaining efficacy. The incidence of postoperative urinary incontinence could be decreased by APUMP, indicating that such preservation facilitates the maintenance of urinary continence after surgery.

Comparison of Safety and Efficacy in Endoscopic Combined Intrarenal Surgery Performed in the Lateral Decubitus and Galdakao-modified Supine Valdivia Positions.

OBJECTIVE: To examine the safety and efficacy of Endoscopic combined intrarenal surgery (ECIRS) between the lateral decubitus (LD) and Galdakao-modified supine Valdivia (GMSV) position. METHODS: We retrospectively reviewed the records of 226 patients with renal stones who underwent ECIRS in the LD and GMSV positions between 2018 and 2022. Surgeries early in the study period were mainly performed in the GMSV position, while later surgeries were mainly performed in the LD position. RESULTS: The number of patients in the LD and GMSV groups was 119 and 107, respectively. The proportion of patients who had no residual stone fragments >2 mm detected on radiography the day after surgery did not significantly differ between the LD group (91.6%) and the GMSV group (97.2%). Operation time was significantly shorter in the LD group (72 vs 81 minutes; P = .02). Total fluoroscopy time was significantly shorter in the LD group (92 vs 189 seconds; P<.001). Complication rates did not significantly differ between the groups. Among the variables analyzed, the patient position was independently impact on the fluoroscopy time (OR 0.309; 95% CI, 0.167-0.571; P<.001). CONCLUSION: ECIRS in the LD position is safe and effective and associated with shorter fluoroscopy than the GSMV position.

Trans-tract electrocoagulation can decrease the need for postoperative nephrostomy tube after endoscopic combined intrarenal surgery.

AIM: To assess the efficacy and safety of trans-tract electrocoagulation at the end of endoscopic combined intrarenal surgery for renal or ureteral stones. METHODS: The present study included patients who underwent endoscopic combined intrarenal surgery from May 2010 to March 2018. After June 2013, the trans-tract electrocoagulation procedure, to coagulate bleeding from the access tract using a resectscope was carried out at the end of the operation. We compared the patients' background and surgical outcomes between patients with and without trans-tract electrocoagulation. RESULTS: Between the trans-tract electrocoagulation (n = 225) and non-trans-tract electrocoagulation (n = 72) groups, the stone number was significantly smaller (1:2:3 or more, 126:72:27 vs 59:10:3, P = 0.001) and the initial stone-free rates were significantly higher (80% vs 72%, P = 0.006) in the trans-tract electrocoagulation group than in the non-trans-tract electrocoagulation group. Patients experienced a higher nephrostomy tube-free rate (67% vs 26%, P < 0.0001), shorter postoperative catheterization time (2.8 ± 3.8 vs 5.4 ± 5.0 days, P = 0.002) and shorter hospital stay (6.5 ± 3.6 vs 8.8 ± 5.0 days, P = 0.0001) in the trans-tract electrocoagulation group than in the non-trans-tract electrocoagulation group. CONCLUSIONS: Trans-tract electrocoagulation in endoscopic combined intrarenal surgery is a safe and efficient procedure that decreases the need for nephrostomy tube placement after surgery.

Decreased RNA-binding motif 5 expression is associated with tumor progression in gastric cancer.

RNA-binding motif 5 is a putative tumor suppressor gene that modulates cell cycle arrest and apoptosis. We recently demonstrated that RNA-binding motif 5 inhibits cell growth through the p53 pathway. This study evaluated the clinical significance of RNA-binding motif 5 expression in gastric cancer and the effects of altered RNA-binding motif 5 expression on cancer biology in gastric cancer cells. RNA-binding motif 5 protein expression was evaluated by immunohistochemistry using the surgical specimens of 106 patients with gastric cancer. We analyzed the relationships of RNA-binding motif 5 expression with clinicopathological parameters and patient prognosis. We further explored the effects of RNA-binding motif 5 downregulation with short hairpin RNA on cell growth and p53 signaling in MKN45 gastric cancer cells. Immunohistochemistry revealed that RNA-binding motif 5 expression was decreased in 29 of 106 (27.4%) gastric cancer specimens. Decreased RNA-binding motif 5 expression was correlated with histological differentiation, depth of tumor infiltration, nodal metastasis, tumor-node-metastasis stage, and prognosis. RNA-binding motif 5 silencing enhanced gastric cancer cell proliferation and decreased p53 transcriptional activity in reporter gene assays. Conversely, restoration of RNA-binding motif 5 expression suppressed cell growth and recovered p53 transactivation in RNA-binding motif 5-silenced cells. Furthermore, RNA-binding motif 5 silencing reduced the messenger RNA and protein expression of the p53 target gene p21. Our results suggest that RNA-binding motif 5 downregulation is involved in gastric cancer progression and that RNA-binding motif 5 behaves as a tumor suppressor gene in gastric cancer.

Effect of dutasteride on microvessel density in benign prostatic hyperplasia.

AIM: Dutasteride, a dual 5α-reductase inhibitor, is used to treat benign prostatic hyperplasia (BPH). However, its histopathological effects on the morphometrics of blood vessels and glands are still controversial. This study aimed to assess the histopathological effects of dutasteride in cases of BPH in a retrospective manner. PATIENTS AND METHODS: Patients with BPH were administered 0.5 mg of dutasteride daily or left untreated prior to undergoing holmium laser enucleation of the prostate (HoLEP). After HoLEP, remaining prostatic peripheral tissue at the bladder neck and the apex was resected. Each specimen was subjected to hematoxylin/eosin and immunohistochemical staining for CD31, and microvessel density (MVD) was analyzed. RESULTS: In the dutasteride-treated group (n=14), the mean duration of administration was 7.07±2.46 weeks. MVD was significantly lower at the bladder neck side in the dutasteride-treated group than in the control group (p=0.018). CONCLUSION: The present study, to our knowledge for the first time, assessed MVD by evaluating the bladder neck and apex sides of the remaining prostatic peripheral tissue after HoLEP, allowing evaluation of MVD in more detail without intraoperative damage of the peripheral tissue, such as through heat denaturation. Dutasteride reduces MVD in the bladder neck side of the prostate among patients with BPH and may lead to decreased risk of perioperative prostatic urethral bleeding.

Crosstalk between second messengers predicts the motility of the growth cone.

Axon guidance involves multiple second messenger signal transduction pathways. Although each signal transduction pathway has been characterized, only a few studies have examined crosstalk between these cascades. Here, we applied a simultaneous second messenger imaging method to the growth cone and demonstrated correlations between cAMP, cGMP, and Ca(2+). The levels of cAMP and cGMP in non-stimulated freely extending growth cones showed a negative correlation without delay. Although there was no direct correlation between cAMP and Ca(2+), examination of cross correlations using small time windows showed frequent switching behavior from negative to positive and vice versa. Furthermore, spatially asymmetric cAMP and cGMP signals in freely deviating growth cones were visualized directly. These results indicate that we succeed in relating second messenger crosstalk to growth cone deviation and extension, and also indicate the possibility of predicting axon guidance from this second messenger crosstalk.

Knockdown of prothymosin α leads to apoptosis and developmental defects in zebrafish embryos.

Prothymosin alpha (ProTα) is an abundant nuclear protein involved in cellular processes intricately linked to development, such as cell proliferation and apoptosis. Although it is known that ProTα inhibits the formation of apoptosome and blocks caspase-3 activity, its mechanism of function in the apoptotic machinery is still under investigation. We have studied the cellular role of ProTα by knocking down its expression in HeLa cells with small hairpin RNA (shRNA) in the absence of apoptotic stimuli. Flow cytometric analysis showed that the live cell population was significantly decreased with a concomitant increase of the apoptotic populations. To understand the physiological role of ProTα within the context of embryonic development, we knocked down the Ptmab zebrafish ortholog using 2 specific morpholino oligonucleotides. Ptmab morphants exhibited growth retardation, bended trunks, and curly tails. The frequency of occurrence of the phenotypic defects was increased in a morpholino dose-dependent manner. Co-injection of ptmaa mRNA with ptmab morpholino partially rescued the morphological defects. Immunostaining with the anti-phospho-histone H3 (pH3) antibody suggested that the abnormalities of Ptmab morphants could be due to defective cell proliferation that results in growth imbalances. TUNEL fluorescent labelling and Acridine Orange staining of the morphants showed high rates of cell death in the head and tail regions. Concomitantly, the active form of caspase-3 was detected in Ptmab morphants. Our data suggest a conserved anti-apoptotic role of ProTα between zebrafish and humans, and provide the first evidence that ProTα is important for early embryogenesis.

Large solid-pseudopapillary neoplasm of the pancreas with aberrant protein expression and mutation of ß-catenin: a case report and literature review of the distribution of ß-catenin mutation.

Solid-pseudopapillary neoplasms (SPN) are rare pancreatic tumors. The etiology of SPN involves mutations in the gene that encodes ß-catenin (CTNNB1). We herein report the case of a 23-year-old woman with a large SPN with proliferating tumor cells that displayed both solid and pseudo-papillary patterns. The simultaneous nuclear accumulation and loss of membrane localization of ß-catenin and E-cadherin was specifically observed in the tumor cells. Further, the tumor cells were shown to harbor a missense mutation in exon 3 of CTNNB1. We also present a review of the literature describing the clustering of CTNNB1 mutations in patients with SPN.

Expansion of CD4(+)CD25 (+) regulatory T cells from cord blood CD4(+) cells using the common γ-chain cytokines (IL-2 and IL-15) and rapamycin.

Rapamycin has important roles in the modulation of regulatory T cells. We tried to expand CD4(+)CD25(+) regulatory T cells (Treg cells) from umbilical cord blood (CB) CD4-positive cells using interleukin (IL)-15 or IL-2 with transforming growth factor (TGF)-ß and rapamycin. We were able to obtain more than 500-fold expansion of CD4(+)CD25(+) cells from CB CD4(+) cells using IL-15 and TGF-ß with rapamycin. These expanded CD4(+)CD25(+) cells expressed forkhead box P3 (FoxP3) mRNA at a level about 100-fold higher and could suppress allogeneic mixed lymphocyte culture (MLC) by more than 50%. Early after rapamycin stimulation, CB CD4(+) cells showed increased expression of FoxP3 and a serine/threonine kinase Pim2 and sustained expression of negative phosphoinositide 3-kinase regulator phosphatase and tensin homolog deleted on chromosome 10 (PTEN). On the other hand, CD4(+)CD25(+) cells expanded with rapamycin for 8 days showed much higher levels of FoxP3 mRNA expression and decreased expression of PTEN. A comparison of IL-15 stimulation and IL-2 stimulation showed slightly higher efficiency of IL-15 for expansion of CD4(+)CD25(+) cells, and for FoxP3 expression, IL-15 also showed significantly higher efficacy for inhibition of MLC. The combination of the common γ-chain cytokine IL-15, TGF-ß, and rapamycin may be a useful means for expanding Treg cells. Pim2 expression early after stimulation with rapamycin may be important for conferring rapamycin resistance for growth of Treg cells. IL-15 is not less useful than IL-2 for expansion of Treg cells.

p53 transactivation is involved in the antiproliferative activity of the putative tumor suppressor RBM5.

RBM5 (RNA-binding motif protein 5) is a nuclear RNA binding protein containing 2 RNA recognition motifs. The RBM5 gene is located at the tumor suppressor locus 3p21.3. Deletion of this locus is the most frequent genetic alteration in lung cancer, but is also found in other human cancers. RBM5 is known to induce apoptosis and cell cycle arrest but the molecular mechanisms of RBM5 function are poorly understood. Here, we show that RBM5 is important for the activity of the tumor suppressor protein p53. Overexpression of RBM5 enhanced p53-mediated inhibition of cell growth and colony formation. Expression of RBM5 augmented p53 transcriptional activity in reporter gene assays and resulted in increased mRNA and protein levels for endogenous p53 target genes. In contrast, shRNA-mediated knockdown of endogenous RBM5 led to decreased p53 transcriptional activity and reduced levels of mRNA and protein for endogenous p53 target genes. RBM5 affected protein, but not mRNA, levels of endogenous p53 after DNA damage suggest that RBM5 contributes to p53 activity through post-transcriptional mechanisms. Our results show that RBM5 contributes to p53 transcriptional activity after DNA damage and that growth suppression and apoptosis mediated by RBM5 are linked to activity of the tumor suppressor protein p53.

[Case of hepatocellular carcinoma with abdominis muscle metastasis].

A 73-year-old man with liver cirrhosis type C, who was diagnosed as having hepatocellular carcinoma (HCC), underwent left lobectomy in March 2005. Two years later, intrahepatic recurrence was found, and he was treated with transcatheter arterial chemoembolization as well as hepatic arterial infusion. In July 2007, he complained of a painless mass over the right abdomen and demonstrated an elevated serum alpha-fetoprotein level. Computed tomography demonstrated a 3.0 cm lesion in the rectus muscle of the abdomen, which was histologically diagnosed as an intramuscular metastasis of HCC. Because there was no history of percutaneous abdominal procedures in this patient, it was suggested that this tumor had hematogeneously metastasized to the rectus muscle of the abdomen.

Endoscopic follow-up of 3 cases with gastrointestinal tract involvement of mantle cell lymphoma.

Gastrointestinal (GI) tract involvement of mantle cell lymphoma (MCL) presents as a variety of forms, ranging from multiple lymphomatous polyposis (MLP) to a slight mucosal change. We report 3 cases with GI tract involvement of MCL who were followed-up by endoscopy. The present study shows three new informations. MLP of the esophagus is rare, but it was observed in two of 3 patients who were extensively involved by MCL. Endoscopic follow-up in one patient suggested that lymphoma cells of MCL had invaded the lamina propria to submucosal layer before MLP developed. Two of the 3 cases showed a favorable clinical course with single-agent rituximab therapy.

Low-grade dysplasia component in early invasive squamous cell carcinoma of the esophagus.

BACKGROUND AND AIMS: It has not been determined whether low-grade squamous dysplasia (LGD) of the esophagus is a precancerous lesion or not. If LGD progresses to squamous cell carcinoma, early carcinoma lesions that have such a natural history might contain a remaining LGD component. METHODS: The lesions in the 68 patients with early invasive squamous cell carcinoma who underwent endoscopic mucosal resection were examined for the presence of an LGD component. If LGD components were observed, the degrees of architectural and cytological abnormalities of LGD components and those of tumor invasive fronts in the same lesions were studied. The degrees of abnormalities of 28 small LGD lesions were also studied. RESULTS: Histological examination of resected specimens confirmed LGD components in 43% of the squamous cell carcinoma lesions. The lesions of lamina propria mucosae (m2) cancer contained a significantly broader area of LGD component than did the lesions of muscularis mucosae (m3) and submucosal layer (sm) cancer (P = 0.037). Mean score for the degrees of cytological abnormalities of LGD component was similar to that of tumor invasive front (P = 0.457) and significantly higher than that of small LGD lesions (P < 0.001). CONCLUSION: Our results indicate the possibility that the lesion was formed by a combination of small lesions that arose as a multicentric occurrence of squamous cell carcinoma and dysplasia. Our results also suggest that an LGD component would transform to carcinoma along with tumor progression. However, the concept of 'basal cell layer type carcinoma in situ' may be suitable for squamous cell lesions with a high degree of cytological abnormalities confined to the lower half of the epithelium.

Increased number of CD16(+)CD56(dim) NK cells in peripheral blood mononuclear cells after allogeneic cord blood transplantation.

In the present study, we investigated subpopulations of natural killer (NK) cells and the expression of stimulatory and inhibitory NK receptors after adult blood and bone marrow transplantation (BBMT) and cord blood transplantation (CBT). There were significant increases in CD16(+)CD56(dim) cell proportion and in absolute number in peripheral blood mononuclear cells (PBMC) during a period of 4-9 months after CBT compared with these in normal PBMC, cord blood (CB), and in PBMC after BBMT. Also, increased numbers of CD16(+)CD56(dim) NK cells were sustained in some patients until 4 years after CBT. This CD16(+)CD56(dim) cell subset after CBT exhibited decreased expression of NKG2A compared with that in CB and increased expression of NKG2C. Purified CD16(+)CD56(dim) cells from patients 8-9 months after CBT exhibited significantly higher levels of cytolytic activity against K562 than did purified CD16(+)CD56(bright) cells and also whole PBMC. The CD16(+)CD56(dim) cell subset with a high level of cytolytic activity significantly increased after CBT, and these cells may be responsible for NK cell-mediated immunity after CBT.

Aldosterone-stimulated SGK1 activity mediates profibrotic signaling in the mesangium.

Several recent reports support the hypothesis that aldosterone contributes to the progression of renal injury. Mineralocorticoids increase the expression of serum- and glucocorticoid-inducible protein kinase 1 (SGK1), which is upregulated in several fibrotic diseases. It was hypothesized that SGK1 may mediate the effects of aldosterone on glomerular fibrosis and inflammation. In primary cultures of rat mesangial cells, aldosterone stimulated the expression, phosphorylation, and kinase activity of SGK1, as well as SGK1-dependent NF-kappaB activity. Furthermore, aldosterone augmented the promoter activity and protein expression of intercellular adhesion molecule-1 (ICAM-1), which modulates the inflammatory response, and the profibrotic cytokine connective tissue growth factor (CTGF) in an SGK1- and NF-kappaB-dependent manner. Similar to the in vitro results, uninephrectomized rats that were treated with aldosterone demonstrated increased glomerular expression of SGK1, ICAM-1, and CTGF proteins than untreated rats; these changes were accompanied by hypertension, glomerulosclerosis, and inflammation. In conclusion, these findings suggest that aldosterone stimulates ICAM-1 and CTGF transcription via the activation of SGK1 and NF-kappaB, effects that may contribute to the progression of aldosterone-induced mesangial fibrosis and inflammation.

Important role of apoptosis signal-regulating kinase 1 in ischemic acute kidney injury.

We investigated the role of apoptosis signal-regulating kinase 1 (ASK1) in ischemia/reperfusion (I/R)-induced acute kidney injury (AKI). Blood urea nitrogen (BUN) and serum creatinine were significantly higher in ASK1+/+ mice than in ASK1-/- mice after I/R injury. Renal histology of ASK1+/+ mice showed significantly greater tubular necrosis and degradation. In ASK1-/- mice, phosphorylation of ASK1, JNK, and p38K, and the number of TUNEL-positive cells and infiltrated leukocytes decreased after I/R injury. Apoptotic changes were significantly decreased in cultured renal tubular epithelial cells (TECs) from ASK1-/- mice under hypoxic condition. Transfection with dominant-active ASK1 induced apoptosis in TECs. Protein expression of monocyte chemoattractant protein-1 (MCP-1) was significantly weaker in ASK1-/- mice after I/R injury. Transfection with dominant negative-ASK1 significantly decreased MCP-1 production in TECs. These results demonstrated that ASK1 is activated in I/R-induced AKI, and blockage of ASK1 attenuates renal tubular apoptosis, MCP-1 expression, and renal function.

Expansion of natural killer cell receptor (CD94/NKG2A)-expressing cytolytic CD8 T cells and CD4+CD25+ regulatory T cells from the same cord blood unit.

OBJECTIVE: Cord blood contains a significant number of precursor cells that differentiate to cytotoxic effector cells and immunoregulatory cells. We tried to expand inhibitory natural killer cell receptor CD94-expressing CD8 T cells with cytolytic activity and CD4(+)CD25(+) regulatory T cells from the same cord cell unit. METHODS: Cytotoxic CD94-expressing CD8 T cells were expanded from CD4-depleted cord blood using an immobilized anti-CD3 monoclonal antibody and a cytokine and also CD4(+)CD25(+) regulatory T cells were expanded from a CD4-enriched fraction derived from the same cord blood unit using anti-CD3/CD28 monoclonal antibody-coated Dynabeads and cytokines. RESULTS: We were able to obtain a more than 1000-fold expansion of CD94-expressing CD8 T cells and a more than 50-fold expansion of CD4(+)CD25(+) cells from the same cord blood unit. These expanded CD4(+)CD25(+) cells expressed FoxP3 mRNA at a level about 100-fold higher than that in isolated CD25(-) cells and could suppress allogeneic mixed lymphocyte culture by >80% (effector cells: CD4(+)CD25(+) cells = 2:1). Cytolytic activities of purified CD94-expressing cells detected by a 4-hour (51)Cr release assay against K562 were >60%. Coculture of CD94-expressing cells with expanded CD4(+)CD25(+) cells did not have any effect on cytolytic activities of purified CD94-expressing cells against K562 cells. CONCLUSION: These expanded cytolytic CD94-expressing CD8 cells might be able to induce a graft-vs-leukemia effect without enhancing graft-vs-host disease, and CD4(+)CD25(+) cells might be able to suppress allogeneic responses, including graft-vs-host disease and graft rejection after cord blood transplantation.

Genetic diversity and reassortments among Akabane virus field isolates.

Sequencing and phylogenetic analysis were carried out for 35 Akabane virus (AKAV) field isolates collected from Japan, Taiwan, Australia and Kenya, and for one Tinaroo virus (TINV). Of the three RNA segments, the M RNA segment encoding the glycoproteins that induce neutralization antibodies was the most variable among the isolates. The difference in the M RNA segments among Asian (Japanese and Taiwanese) isolates was not large (<12.3% nucleotide (nt) and <5.9% amino acid (aa) differences), rather than those between Asian and Australian isolates (13.4-14.9% nt and 6.2-8.2% aa difference). In phylogenetic trees, the Australian isolates form a separate branch from Asian isolates. All three RNA segments of the Kenyan isolate MP496 were genetically distant from those of the other AKAV field isolates. Although the S and L RNA segments of TINV, which is regarded as a strain of AKAV, was closely related to those of the Asian and Australian AKAV isolates, the M RNA was divergent that of the most distant AKAV isolate, MP496. Discrepancies among the phylogenetic trees of the S, M and L RNA segments indicate genomic reassortment events among AKAV field isolates.

Overexpression of the oncoprotein prothymosin alpha triggers a p53 response that involves p53 acetylation.

Activation of the tumor suppressor protein p53 is a critical cellular response to various stress stimuli and to inappropriate activity of growth-promoting proteins, such as Myc, Ras, E2F, and beta-catenin. Protein stability and transcriptional activity of p53 are modulated by protein-protein interactions and post-translational modifications, including acetylation. Here, we show that inappropriate activity of prothymosin alpha (PTMA), an oncoprotein overexpressed in human cancers, triggers a p53 response. Overexpression of PTMA enhanced p53 transcriptional activity in reporter gene assays for p53 target gene promoters hdm2, p21, and cyclin G. Overexpressed PTMA resulted in increased mRNA and protein levels for endogenous p53 target genes, hdm2 and p21, and in growth suppression. In contrast, reduction of endogenous PTMA through RNA interference decreased p53 transcriptional activity. Histone acetyltransferases (HATs) act as p53 coactivators and acetylate p53. PTMA, known to interact with HATs, led to increased levels of acetylated p53. PTMA did not increase the transcriptional activity of an acetylation-deficient p53 mutant, suggesting that p53 acetylation is an indispensable part of the p53 response to PTMA. Chromatin immunoprecipitation assays showed that excess PTMA associates with the p21 promoter and results in increased levels of acetylated p53 at the p21 promoter. Our findings indicate that overexpressed PTMA elicits a p53 response that involves p53 acetylation.

Wnt4-transformed mouse embryonic stem cells differentiate into renal tubular cells.

Embryonic stem (ES) cells have the potential to differentiate into various progenitor cells. Here we investigated the capacity of mouse ES cells to differentiate into renal tubular cells both in vitro and in vivo. After stably transfecting Wnt4 cDNA to mouse ES cells (Wnt4-ES cells), undifferentiated ES cells were incubated by the hanging drop culture method to induce differentiation to embryoid bodies (EBs). During culturing of the EBs derived from the Wnt4-ES cells, aquaporin-2 (AQP2) mRNA and protein were expressed within 15-20 days. The expression of AQP2 in Wnt4-EBs was enhanced in the presence of hepatocyte growth factor (HGF) and activin A. We next performed in vivo experiments by transplanting the Wnt4-EBs into the mouse renal cortex. Four weeks after transplantation, some portions of the EB-derived cells expressing AQP2 in the kidney assembled into tubular-like formations. In conclusion, our in vitro and in vivo experiments revealed two new findings: first, that cultured Wnt4-EBs have an ability to differentiate into renal tubular cells; and second, that Wnt4, HGF, and activin A may promote the differentiation of ES cells to renal tubular cells.