CD36 facilitates fatty acid uptake by dynamic palmitoylation-regulated endocytosis.

Fatty acids (FAs) are essential nutrients, but how they are transported into cells remains unclear. Here, we show that FAs trigger caveolae-dependent CD36 internalization, which in turn delivers FAs into adipocytes. During the process, binding of FAs to CD36 activates its downstream kinase LYN, which phosphorylates DHHC5, the palmitoyl acyltransferase of CD36, at Tyr91 and inactivates it. CD36 then gets depalmitoylated by APT1 and recruits another tyrosine kinase SYK to phosphorylate JNK and VAVs to initiate endocytic uptake of FAs. Blocking CD36 internalization by inhibiting APT1, LYN or SYK abolishes CD36-dependent FA uptake. Restricting CD36 at either palmitoylated or depalmitoylated state eliminates its FA uptake activity, indicating an essential role of dynamic palmitoylation of CD36. Furthermore, blocking endocytosis by targeting LYN or SYK inhibits CD36-dependent lipid droplet growth in adipocytes and high-fat-diet induced weight gain in mice. Our study has uncovered a dynamic palmitoylation-regulated endocytic pathway to take up FAs.

DHHC4 and DHHC5 Facilitate Fatty Acid Uptake by Palmitoylating and Targeting CD36 to the Plasma Membrane.

Fatty acid uptake is the first step in fatty acid utilization, but it remains unclear how the process is regulated. Protein palmitoylation is a fatty acyl modification that plays a key regulatory role in protein targeting and trafficking; however, its function in regulating fatty acid metabolism is unknown. Here, we show that two of the Asp-His-His-Cys (DHHC) motif-containing palmitoyl acyltransferases, DHHC4 and DHHC5, regulate fatty acid uptake. DHHC4 and DHHC5 function at different subcellular localizations to control the palmitoylation, plasma membrane localization, and fatty acid uptake activity of the scavenger receptor CD36. Depletion of either DHHC4 or DHHC5 in cells disrupts CD36-dependent fatty acid uptake. Furthermore, both Dhhc4-/- and adipose-specific Dhhc5 knockout mice show decreased fatty acid uptake activity in adipose tissues and develop severe hypothermia upon acute cold exposure. These findings demonstrate a critical role of DHHC4 and DHHC5 in regulating fatty acid uptake.

Prefabricated partial distal urethral in 2-staged repair of proximal hypospadias with severe chordee.

PURPOSE: To describe a new technique for staged hypospadias repair in which the urethral plate is divided and tubularized transverse island flap prefabricated partial distal urethral at the time of the first stage. MATERIALS AND METHODS: Sixteen patients with proximal hypospadias associated with severe chordee were operated on using a new staged technique. At the time of the first stage, the urethral plate was divided and chordee was corrected. Then tubularized transverse island flap was used to prefabricate partial distal urethra. The defective urethra was repaired using the Thiersch-Duplay principle at the second stage. RESULTS: All participants have completed both stages of the operation. The mean follow-up duration was 18.4 months (range from 6 to 72 months). In the first-stage surgery, the modified tabularized transverse preputial island flap was performed on 6 patients, whereas the modified preputial double-faced island flap was performed on the other 10 patients. All of the prefabricated partial distal neourethras had no evidence of stenosis or scarring. The result of the second-stage procedure was a complete penis with integrated urethral. All patients were satisfied with cosmetic and functional results. Neither stricture nor diverticula was observed. A good urinary stream during the urination was attained in 12 (75.0%) patients. Four cases (25.0%) developed urethrocutaneous fistula after the second stage repair. CONCLUSIONS: In our preliminary series, this procedure improved functional and cosmetic results. It may be applicable to most cases of proximal hypospadias. Even when complications occur, they are less severe compared to those of the traditional staged approach.

Meta-analysis of gene expression data identifies causal genes for prostate cancer.

Prostate cancer is a leading cause of death in male populations across the globe. With the advent of gene expression arrays, many microarray studies have been conducted in prostate cancer, but the results have varied across different studies. To better understand the genetic and biologic mechanisms of prostate cancer, we conducted a meta-analysis of two studies on prostate cancer. Eight key genes were identified to be differentially expressed with progression. After gene co-expression analysis based on data from the GEO database, we obtained a co- expressed gene list which included 725 genes. Gene Ontology analysis revealed that these genes are involved in actin filament-based processes, locomotion and cell morphogenesis. Further analysis of the gene list should provide important clues for developing new prognostic markers and therapeutic targets.

[Urethroplasty with circular fasciocutaneous flap in the treatment of complex anterior urethral strictures].

OBJECTIVE: To summarize the experience of urethral reconstruction using circular fasciocutaneous flap for the treatment of complex anterior urethral strictures. METHOD: The circular fasciocutaneous flap was harvested from the distal penile shaft or foreskin. Then the circular configuration was converted into longitudinal strip of skin which was rotated to ventral side to repair the exposured urethral strictures using the ventral onlay method. The surveillance protocol after urethroplasty was urination observation, regularly uroflowmetry and urethrography examination. RESULTS: From Nov. 2006 to Oct. 2012, 15 cases were treated. The mean age was 45 years (20-76 years) and mean follow-up period was 18 months(3 months-3 years). Stricture was caused by chronic urethritis in 4 cases, long-term urethral catheterization in 3 cases, transurethral perfusion chem other aphy in 3 cases, transurethral prostatectomy in 3 cases and hypospadias after surgery in 2 patients. The mean stricture length was 7.0 cm (3.5-12.0 cm). The overall success rate was 80.0% (12/15). Recurrence stenosis was noted in 2 cases and diverticulum formation in 1 case. CONCLUSIONS: The penile circular fasciocutaneous flap can be used for anterior urethral stricture in nearly any length. The flap has the characteristics of hairless, adequate mobile and length, well-vascularized pedicle and easy to harvest. The onlay reconstruction provides excellent cosmetic results, less trauma, higher success rate. Therefore it should be one of the preferred techniques for complex anterior urethral stricture repair.

[Value of spermatic cord sonography in the early diagnosis and treatment of testicular torsion].

OBJECTIVE: To improve the early diagnosis and therapeutic outcomes of testicular torsion. METHODS: We retrospectively reviewed the clinical data of 49 cases of testicular torsion along with the results of their intratesticular color Doppler flow imaging (CDFI) and spermatic cord sonography. RESULTS: Of the 49 cases, 42 showed abnormal intratesticular blood flow, including 3 cases of increased blood flow, while the other 7 presented no obvious abnormality. Morphological abnormality of the spermatic cord was found in 47 cases. Twenty-eight cases underwent testis removal, and the other 21 received detorsion and orchidopexy, in which 12 testes were preserved with normal size and blood flow. CONCLUSION: Spermatic cord sonography and intratesticular CDFI play an important role in the early diagnosis of testicular torsion. And early surgical exploration contributes to the preservation of the testis.

[The effect of cell killing by ABT-737 synergized with docetaxel in human prostate cancer PC-3 cells].

OBJECTIVE: To investigate the synergistical killing effect of docetaxel combined with ABT-737 on human prostate cancer cell line PC-3 by inducing apoptosis and further to determine the mechanism underlying such effect. METHODS: PC-3 cells were treated with various concentrations of docetaxel or (and) ABT-737. Cell viability was determined using MTT assay. Apoptosis was assessed by fluorescence microscopy analysis of cells with condensed and segmented nuclei following staining with 4',6-diamidino-2-phenylindole (DAPI). Cellular DNA was stained with propidium iodide and flow cytometric analysis was performed to analyze the cell cycle distribution. Bcl-2, Bax, Bcl-xL and Mcl-1 protein changes were detected by Western blot. The activity of caspase-3 was measured using a colorimetric assay. RESULTS: Docetaxel (20 nmol/L) combination with ABT-737 (400 nmol/L) for 48 hours, the cell viability was decreased to 19.7% ± 3.2% to compare with 44.2% ± 4.4% (t = 4.45) of docetaxel and 93.2% ± 1.8% of ABT-737 separately and there was a synergistic effect between the two drugs (CI = 0.8). Apoptosis rate of the combination group was higher than other two drugs. Docetaxel increased the cell number arrested in G(2)/M phase compared with control group (P < 0.05), but the combination treatment resulted in a significant arrest in the G(0)/G(1) phase. The combination treatment could significantly reduced the Bcl-2, Bcl-xL and Mcl-1 expression (F = 369.53, 57.89 and 32.77, all P < 0.05) and enhanced the activity of caspase-3 (419.7% ± 15.6%) (F = 207.33, P < 0.05). CONCLUSIONS: The combination of ABT-737 with docetaxel can synergistically inhibit the proliferation of PC-3 cells through inducing apoptosis, which may be associated with cell cycle arrest, down-regulation of Bcl-2, Bcl-xL and Mcl-1 expression and activation of caspase-3.