Oxidative Stress-Mediated RUNX3 Mislocalization Occurs Via Jun Activation Domain-Binding Protein 1 and Histone Modification

Runt domain transcription factor 3 (RUNX3) suppresses many different cancer types and is disabled by mutations, epigenetic repression, or cytoplasmic mislocalization. In this study, we investigated whether oxidative stress is associated with RUNX3 accumulation from the nucleus to the cytoplasm in terms of histone modification. Oxidative stress elevated histone deacetylase (HDAC) level and lowered that of histone acetyltransferase. In addition, oxidative stress decreased the expression of mixed lineage leukemia (MLL), a histone methyltransferase, but increased the expression of euchromatic histone-lysine N-methyltransferase 2 (EHMT2/G9a), which is also a histone methyltransferase. Moreover, oxidative stress-induced RUNX3 phosphorylation, Src activation, and Jun activation domain-binding protein 1 (JAB1) expression were inhibited by knockdown of HDAC and G9a, restoring the nuclear localization of RUNX3 under oxidative stress. Cytoplasmic RUNX3 localization was followed by oxidative stress-induced histone modification, activated Src along with RUNX3 phosphorylation, and induction of JAB1, resulting in RUNX3 inactivation.

Exogenous spermidine ameliorates tubular necrosis during cisplatin nephrotoxicity

The hallmark of cisplatin-induced acute kidney injury is the necrotic cell death in the kidney proximal tubules. However, an effective approach to limit cisplatin nephrotoxicity remains unknown. Spermidine is a polyamine that protects against oxidative stress and necrosis in aged yeasts, and the present study found that exogenous spermidine markedly attenuated tubular necrosis and kidney dysfunction, but not apoptosis, during cisplatin nephrotoxicity. In addition, exogenous spermidine potently inhibited oxidative/nitrative DNA damage, poly(ADP-ribose) polymerase 1 (PARP1) activation and ATP depletion after cisplatin injection. Conversely, inhibition of ornithine decarboxylase (ODC) via siRNA transfection in vivo significantly increased DNA damage, PARP1 activation and ATP depletion, resulting in acceleration of tubular necrosis and kidney dysfunction. Finally, exogenous spermidine removed severe cisplatin injury induced by ODC inhibition. In conclusion, these data suggest that spermidine protects kidneys against cisplatin injury through DNA damage and tubular necrosis, and this finding provides a novel target to prevent acute kidney injury including nephrotoxicity.

Exogenous CGRP upregulates profibrogenic growth factors through PKC/JNK signaling pathway in kidney proximal tubular cells

Kidney denervation prevents the development of tubulointerstitial fibrosis, but the neuropeptide calcitonin gene-related peptide (CGRP) in the denervated kidneys restores the fibrotic feature through the upregulation of profibrogenic growth factors. CGRP is involved in aggravation of inflammation by increasing the number of circulating cells and chemotactic factors. However, it is not clear how CGRP contributes to the upregulation of profibrogenic factors during fibrogenesis. In both human and pig kidney proximal tubular cell lines, administration of 1 nM CGRP significantly increased the levels of transforming growth factor-β1 (TGF-β1) production and connective tissue growth factor (CTGF) expression at 6 and 24 h after the administration. Exogenous CGRP also increased the TGF-β1 and CTGF protein levels in the incubation media, indicating release of these proteins from the cells. Treatment with 100 nM CGRP receptor antagonist (CGRP^8-37) for 24 h significantly inhibited the increase in intracellular levels and released levels of TGF-β1 and CTGF in CGRP-treated cells. Genetic inhibition of CGRP receptor using siRNA transfection also suppressed the increase in TGF-β1 production and release at 24 h after CGRP stimulation. Furthermore, treatment with a specific protein kinase C (PKC) inhibitor chelerythrine (1 thru 10 μM) markedly reduced the upregulation and release of TGF-β1 and CTGF 6 h after CGRP administration. Finally, inhibition of c-Jun N-terminal protein kinase (JNK) phosphorylation using 1 μM SP600125 prevented the increase in TGF-β1 and CTGF upregulation and release 6 h after CGRP administration. Consistent with the in vitro data, exogenous CGRP in denervated UUO kidneys upregulated and secreted TGF-β1 and CTGF in dependence on PKC activation and JNK phosphorylation. In conclusion, these data suggest that exogenous CGRP induces the upregulation and secretion of profibrogenic TGF-β1 and CTGF proteins through the CGRP receptor/PKC/JNK signaling pathway in kidney proximal tubular cells.

Poly(ADP-ribose) polymerase 1 contributes to oxidative stress through downregulation of sirtuin 3 during cisplatin nephrotoxicity

Enhanced oxidative stress is a hallmark of cisplatin nephrotoxicity, and inhibition of poly(ADP-ribose) polymerase 1 (PARP1) attenuates oxidative stress during cisplatin nephrotoxicity; however, the precise mechanisms behind its action remain elusive. Here, using an in vitro model of cisplatin-induced injury to human kidney proximal tubular cells, we demonstrated that the protective effect of PARP1 inhibition on oxidative stress is associated with sirtuin 3 (SIRT3) activation. Exposure to 400 µM cisplatin for 8 hours in cells decreased activity and expression of manganese superoxide dismutase (MnSOD), catalase, glutathione peroxidase (GPX), and SIRT3, while it increased their lysine acetylation. However, treatment with 1 µM PJ34 hydrochloride, a potent PARP1 inhibitor, restored activity and/or expression in those antioxidant enzymes, decreased lysine acetylation of those enzymes, and improved SIRT3 expression and activity in the cisplatin-injured cells. Using transfection with SIRT3 double nickase plasmids, SIRT3-deficient cells given cisplatin did not show the ameliorable effect of PARP1 inhibition on lysine acetylation and activity of antioxidant enzymes, including MnSOD, catalase and GPX. Furthermore, SIRT3 deficiency in cisplatin-injured cells prevented PARP1 inhibition-induced increase in forkhead box O3a transcriptional activity, and upregulation of MnSOD and catalase. Finally, loss of SIRT3 in cisplatin-exposed cells removed the protective effect of PARP1 inhibition against oxidative stress, represented by the concentration of lipid hydroperoxide and 8-hydroxy-2'-deoxyguanosine; and necrotic cell death represented by a percentage of propidium iodide–positively stained cells. Taken together, these results indicate that PARP1 inhibition protects kidney proximal tubular cells against oxidative stress through SIRT3 activation during cisplatin nephrotoxicity.

NEDDylation promotes stress granule assembly

Stress granules (SGs) harbour translationally stalled messenger ribonucleoproteins and play important roles in regulating gene expression and cell fate. Here we show that neddylation promotes SG assembly in response to arsenite-induced oxidative stress. Inhibition or depletion of key components of the neddylation machinery concomitantly inhibits stress-induced polysome disassembly and SG assembly. Affinity purification and subsequent mass-spectrometric analysis of Nedd8-conjugated proteins from translationally stalled ribosomal fractions identified ribosomal proteins, translation factors and RNA-binding proteins (RBPs), including SRSF3, a previously known SG regulator. We show that SRSF3 is selectively neddylated at Lys85 in response to arsenite. A non-neddylatable SRSF3 (K85R) mutant do not prevent arsenite-induced polysome disassembly, but fails to support the SG assembly, suggesting that the neddylation pathway plays an important role in SG assembly.

Poly(ADP-ribose) polymerase regulates glycolytic activity in kidney proximal tubule epithelial cells

After renal injury, selective damage occurs in the proximal tubules as a result of inhibition of glycolysis. The molecular mechanism of damage is not known. Poly(ADP-ribose) polymerase (PARP) activation plays a critical role of proximal tubular cell death in several renal disorders. Here, we studied the role of PARP on glycolytic flux in pig kidney proximal tubule epithelial LLC-PK1 cells using XFp extracellular flux analysis. Poly(ADP-ribosyl)ation by PARP activation was increased approximately 2-fold by incubation of the cells in 10 mM glucose for 30 minutes, but treatment with the PARP inhibitor 3-aminobenzamide (3-AB) does-dependently prevented the glucose-induced PARP activation (approximately 14.4% decrease in 0.1 mM 3-AB–treated group and 36.7% decrease in 1 mM 3-AB–treated group). Treatment with 1 mM 3-AB significantly enhanced the glucose-mediated increase in the extracellular acidification rate (61.1±4.3 mpH/min vs. 126.8±6.2 mpH/min or approximately 2-fold) compared with treatment with vehicle, indicating that PARP inhibition increases only glycolytic activity during glycolytic flux including basal glycolysis, glycolytic activity, and glycolytic capacity in kidney proximal tubule epithelial cells. Glucose increased the activities of glycolytic enzymes including hexokinase, phosphoglucose isomerase, phosphofructokinase-1, glyceraldehyde-3-phosphate dehydrogenase, enolase, and pyruvate kinase in LLC-PK1 cells. Furthermore, PARP inhibition selectively augmented the activities of hexokinase (approximately 1.4-fold over vehicle group), phosphofructokinase-1 (approximately 1.6-fold over vehicle group), and glyceraldehyde-3-phosphate dehydrogenase (approximately 2.2-fold over vehicle group). In conclusion, these data suggest that PARP activation may regulate glycolytic activity via poly(ADP-ribosyl)ation of hexokinase, phosphofructokinase-1, and glyceraldehyde-3-phosphate dehydrogenase in kidney proximal tubule epithelial cells.

Neck muscle atrophy and soft-tissue fibrosis after neck dissection and postoperative radiotherapy for oral cancer

Late complications of head and neck cancer survivors include neck muscle atrophy and soft-tissue fibrosis. We present an autopsy case of neck muscle atrophy and soft-tissue fibrosis (sternocleidomastoid, omohyoid, digastric, sternohyoid, sternothyroid, and platysma muscles) within the radiation field after modified radical neck dissection type I and postoperative radiotherapy for floor of mouth cancer. A 70-year-old man underwent primary tumor resection of the left floor of mouth, left marginal mandibulectomy, left modified radical neck dissection type I, and reconstruction with a radial forearm free flap. The patient received adjuvant radiotherapy. The dose to the primary tumor bed and involved neck nodes was 63 Gy in 35 fractions over 7 weeks. Areas of subclinical disease (left lower neck) received 50 Gy in 25 fractions over 5 weeks. Adjuvant chemotherapy was not administered.

A cephalic vein drained into one of the double axillary veins through the pectoralis major muscle

Although the cephalic vein follows a fairly consistent course, numerous variants have been reported. We found a rare anatomical presentation of the cephalic vein in a 43-year-old Korean male cadaver. The cephalic vein had anastomosed with the basilic vein and brachial vein at the level of the elbow, perforated the pectoralis major muscle between the clavicular and sternal heads, and then entered into one of the double axillary veins. Knowledge of the variations on the cephalic vein is important for clinicians as well as anatomists since the approach through the axillary base is favoured in many invasive procedures.

Dual left anterior interventricular coronary artery with a rare course in a Korean

Dual left anterior interventricular coronary artery (also called left anterior descending artery, hereafter referred as LAD) is a rare congenital coronary artery anomaly. Notably, type IV dual LAD has never been reported in Koreans. During a routine dissection, a new variant of type IV dual LAD was found in a 57-year-old Korean male cadaver, whose cause of death was unknown. One LAD originated from the right coronary artery, coursed through the anterior interventricular sulcus, but did not reach the apex cordis. The other LAD arose from the left coronary artery, never entered the anterior interventricular sulcus through its course, but reached the apex cordis, where it met the posterior interventricular branch of the right coronary artery. This is the first report on a new variant of type IV dual LAD in Koreans, which is of clinical importance during procedures containing the coronary artery.

Morphological effects of mitomycin C on urothelial responses to experimentally-induced urethral stricture in rats

OBJECTIVES

To analyze the urothelial responses to mitomycin C treatment after urethral injury in rats, as the urothelium might play a role in the pathogenesis of urethral stricture.

METHODS

Male Sprague-Dawley rats were divided into four groups (n = 5/group): negative control, positive control without further treatment, experimental control treated with sodium hyaluronate and sodium carboxymethylcellulose, and experimental treated with mitomycin C after internal urethrotomy.

RESULTS

Compared with negative controls, positive controls showed a significant increase in cell proliferation and DNA damage accompanied by a considerable decrease in DNA repair in the urothelium, which resulted in urethral stricture. Experimental controls showed a significant increase in cell proliferation, DNA damage and DNA repair compared with negative controls. The mitomycin C-treated group showed a significant decrease in cell proliferation and DNA damage, but a considerable increase in DNA repair compared with the positive and experimental control groups. DNA damage was immediately increased after urethral injury, but DNA repair and cell proliferation showed belated and upregulated expression after mitomycin C treatment.

CONCLUSIONS

Mitomycin C could induce healthy re-epithelialization without severe damage in the urothelium. This finding might support the possibility of using mitomycin C as an adjuvant therapy for urethral strictures, and it might also suggest a urothelial role in the process of urethral stricture after urethral injury.

MicroRNA-22 Suppresses DNA Repair and Promotes Genomic Instability through Targeting of MDC1

MDC1 is critical component of the DNA damage response (DDR) machinery and orchestrates the ensuring assembly of the DDR protein at the DNA damage sites, and therefore loss of MDC1 results in genomic instability and tumorigenicity. However, the molecular mechanisms controlling MDC1 expression are currently unknown. Here, we show that miR-22 inhibits MDC1 translation via direct binding to its 3' untranslated region, leading to impaired DNA damage repair and genomic instability. We demonstrated that activated Akt1 and senescence hinder DDR function of MDC1 by upregulating endogenous miR-22. After overexpression of constitutively active Akt1, homologous recombination was inhibited by miR-22-mediated MDC1 repression. In addition, during replicative senescence and stress-induced premature senescence, MDC1 was downregulated by upregulating miR-22 and thereby accumulating DNA damage. Our results demonstrate a central role of miR-22 in the physiologic regulation of MDC1-dependent DDR and suggest a molecular mechanism for how aberrant Akt1 activation and senescence lead to increased genomic instability, fostering an environment that promotes tumorigenesis.

MicroRNA-22 Suppresses DNA Repair and Promotes Genomic Instability through Targeting of MDC1

MDC1 is critical component of the DNA damage response (DDR) machinery and orchestrates the ensuring assembly of the DDR protein at the DNA damage sites, and therefore loss of MDC1 results in genomic instability and tumorigenicity. However, the molecular mechanisms controlling MDC1 expression are currently unknown. Here, we show that miR-22 inhibits MDC1 translation via direct binding to its 3' untranslated region, leading to impaired DNA damage repair and genomic instability. We demonstrated that activated Akt1 and senescence hinder DDR function of MDC1 by upregulating endogenous miR-22. After overexpression of constitutively active Akt1, homologous recombination was inhibited by miR-22-mediated MDC1 repression. In addition, during replicative senescence and stress-induced premature senescence, MDC1 was downregulated by upregulating miR-22 and thereby accumulating DNA damage. Our results demonstrate a central role of miR-22 in the physiologic regulation of MDC1-dependent DDR and suggest a molecular mechanism for how aberrant Akt1 activation and senescence lead to increased genomic instability, fostering an environment that promotes tumorigenesis.

Cisplatin induces primary necrosis through poly(ADP-ribose) polymerase 1 activation in kidney proximal tubular cells

Treatment with cisplatin for cancer therapy has a major side effect such as nephrotoxicity; however, the role of poly (ADP-ribose) polymerase 1 (PARP1) in necrosis in response to cisplatin nephrotoxicity remains to be defined. Here we report that cisplatin induces primary necrosis through PARP1 activation in kidney proximal tubular cells derived from human, pig and mouse. Treatment with high dose of cisplatin for 4 and 8 hours induced primary necrosis, as represented by the percentage of propidium iodide-positive cells and lactate dehydrogenase release. The primary necrosis was correlated with PARP1 activation during cisplatin injury. Treatment with PJ34, a potent PARP1 inhibitor, at 2 hours after injury attenuated primary necrosis after 8 hours of cisplatin injury as well as PARP1 activation. PARP1 inhibition also reduced the release of lactate dehydrogenase and high mobility group box protein 1 from kidney proximal tubular cells at 8 hours after cisplatin injury. Oxidative stress was increased by treatment with cisplatin for 8 hours as shown by 8-hydroxy-2'-deoxyguanosine and lipid hydroperoxide assays, but PARP1 inhibition at 2 hours after injury reduced the oxidative damage. These data demonstrate that cisplatin-induced PARP1 activation contributes to primary necrosis through oxidative stress in kidney proximal tubular cells, resulting in the induction of cisplatin nephrotoxicity and inflammation.

Poly(ADP-ribose) polymerase 1 activation links ischemic acute kidney injury to interstitial fibrosis

Inactivation of poly(ADP-ribose) polymerase 1 (PARP1) has been found to be protective in several disease models; however, the role of PARP1 in acute kidney injury-induced interstitial fibrosis has not been studied. Herein, we tested whether PARP1 inactivation by treatment with PJ34 (a PARP1 inactivator; 10 mg/kg body weight/day, intraperitoneal implantation of a miniosmotic pump at 2 days after the onset) contributed to the decrease in interstitial fibrosis induced by ischemia-reperfusion injury (IRI) in mouse kidneys. IRI increased PARP1 activation represented by poly(ADP-ribose) expression from 4 to 16 days postinjury, whereas treatment with PJ34 at 2 days after the onset efficaciously abolished the increase in PARP1 activation at 4, 8 and 16 days after IRI. Pharmacological inactivation of PARP1 significantly reduced interstitial fibrosis as represented by the collagen deposition and transforming growth factor-β1 level at 8 and 16 days after IRI. Consistent with collagen deposition, myofibroblast activation represented by α-smooth muscle actin expression was also reduced by PARP1 inactivation at 8 and 16 days after IRI. Furthermore, IRI enhanced macrophage influx, but PARP1 inactivaton remarkably reduced macrophage influx for 4 through 16 days after the injury. Among the chemoattractants for monocytes/macrophages and neutrophils, monocyte chemotactic protein-1 (MCP-1) production in IRI kidneys was significantly reduced by PARP1 inactivation from 4 to 16 days postinjury. These data demonstrate that PARP1 activation contributes to IRI-induced MCP-1 production and in turn to macrophage influx, resulting in the promotion of interstitial fibrosis.

Outcome-based self-assessment on a team-teaching subject in the medical school

We attempted to investigate the reason why the students got a worse grade in gross anatomy and the way how we can improve upon the teaching method since there were gaps between teaching and learning under recently changed integration curriculum. General characteristics of students and exploratory factors to testify the validity were compared between year 2011 and 2012. Students were asked to complete a short survey with a Likert scale. The results were as follows: although the percentage of acceptable items was similar between professors, professor C preferred questions with adequate item discrimination and inappropriate item difficulty whereas professor Y preferred adequate item discrimination and appropriate item difficulty with statistical significance (P<0.01). The survey revealed that 26.5% of total students gave up the exam on gross anatomy of professor Y irrespective of years. These results suggested that students were affected by the corrected item difficulty rather than item discrimination in order to obtain academic achievement. Therefore, professors in a team-teaching subject should reach a consensus on an item difficulty with proper teaching methods.

Pharmacological inhibition of soluble epoxide hydrolase prevents renal interstitial fibrogenesis in obstructive nephropathy

Treating chronic kidney disease (CKD) has been challenging because of its pathogenic complexity. Epoxyeicosatrienoic acids (EETs) are cytochrome P-450-dependent derivatives of arachidonic acid with antihypertensive, anti-inflammatory, and profibrinolytic functions. We recently reported that genetic ablation of soluble epoxide hydrolase (sEH), an enzyme that converts EETs to less active dihydroxyeicosatrienoic acids, prevents renal tubulointerstitial fibrosis and inflammation in experimental mouse models of CKD. Here, we tested the hypothesis that pharmacological inhibition of sEH after unilateral ureteral obstruction (UUO) would attenuate tubulointerstitial fibrosis and inflammation in mouse kidneys and may provide a novel approach to manage the progression of CKD. Inhibition of sEH enhanced levels of EET regioisomers and abolished tubulointerstitial fibrosis, as demonstrated by reduced collagen deposition and myofibroblast formation after UUO. The inflammatory response was also attenuated, as demonstrated by decreased influx of neutrophils and macrophages and decreased expression of inflammatory cytokines keratinocyte chemoattractant, macrophage inflammatory protein-2, monocyte chemotactic protein-1, TNF-α, and ICAM-1 in kidneys after UUO. UUO upregulated transforming growth factor-β1/Smad3 signaling and induced NF-κB activation, oxidative stress, tubular injury, and apoptosis; in contrast, it downregulated antifibrotic factors, including peroxisome proliferator-activated receptor (PPAR) isoforms, especially PPAR-γ. sEH inhibition mitigated the aforementioned malevolent effects in UUO kidneys. These data demonstrate that pharmacological inhibition of sEH promotes anti-inflammatory and fibroprotective effects in UUO kidneys by preventing tubular injury, downregulation of NF-κB, transforming growth factor-β1/Smad3, and inflammatory signaling pathways, and activation of PPAR isoforms. Our data suggest the potential use of sEH inhibitors in treating fibrogenesis in the UUO model of CKD.

Anatomic variations of cervical and high thoracic ligamentum flavum

BACKGROUND

Epidural blocks are widely used for the management of acute and chronic pain. The technique of loss of resistance is frequently adopted to determine the epidural space. A discontinuity of the ligamentum flavum may increase the risk of failure to identify the epidural space. The purpose of this study was to investigate the anatomic variations of the cervical and high thoracic ligamentum flavum in embalmed cadavers.

METHODS

Vertebral column specimens of 15 human cadavers were obtained. After vertebral arches were detached from pedicles, the dural sac and epidural connective tissue were removed. The ligamentum flavum from C3 to T6 was directly examined anteriorly.

RESULTS

The incidence of midline gaps in the ligamentum flavum was 87%-100% between C3 and T2. The incidence decreased below this level and was the lowest at T4-T5 (8%). Among the levels with a gap, the location of a gap in the caudal third of the ligamentum flavum was more frequent than in the middle or cephalic portion of the ligamentum flavum.

CONCLUSIONS

The cervical and high thoracic ligamentum flavum frequently has midline intervals with various features, especially in the caudal portion of the intervertebral space. Therefore, the ligamentum flavum is not always reliable as a perceptible barrier to identify the epidural space at these vertebral levels. Additionally, it may be more useful to insert the needle into the cephalic portion of the intervertebral space than in the caudal portion.

Uncommon branching pattern with a prominent articular ramus of the inferior gluteal artery in a Korean male cadaver

We found a rare case of uncommon branching pattern with a prominent articular ramus of the inferior gluteal artery in a 39-year-old Korean male cadaver, whose cause of death was rectal carcinoma. The inferior gluteal artery branches off downwards at a time, the muscular rami ran in parallel with one another, and the articular ramus gave another muscular branch and has an anastomosis with the medial circumflex femoral artery. Knowledge of vascular variations in the gluteal region may give useful information of versatile flaps for reconstruction and the prominent articular ramus found in this case is good enough to consider the existence of the anastomosis between the medial circumflex femoral artery and the inferior gluteal artery as normal, not rudimentary.

A comparison of the steroidogenic acute regulatory protein-related lipid transfer (START) domain-containing 6 on the brain and testes between young and aged rats

The START domain-containing 6 (StarD6) was originally reported to play a role during male germ cell maturation. We have since reported on StarD6 in the developing hypothyroid rat brain. Therefore, we investigated qualitative and quantitative changes of StarD6 in the aging rat brain and testes of male Sprague-Dawley rats. Serum testosterone levels decreased with aging and total protein levels of StarD6 in the testes decreased. While the immunolocalization of StarD6 in the spermatocytes decreased, cytoplasmic localization appeared in the aged testes. Compared with young rats, aged rats showed decreased StarD6 in the cerebrum and cerebellum without changes in immunolocalization in the cortical neurons of the cerebral cortex and Purkinje cells of the cerebellar cortex. Aged rats also showed increases in StarD6 in the hippocampus with changes in its immunolocalization from the Stratum pyramidale to the Stratum radiatum and Stratum lacunosum-moleculare. Taken together, StarD6 decreased with aging in the testes, which implies that StarD6 might play a role in impaired spermatogenesis in the aged rat. StarD6 decreased in the cerebrum and the cerebellum, but slightly increased in the hippocampus, which suggests that StarD6 might also play a role for neurosteroidogenesis in the hippocampus of aged rats.

An accessory belly of the sternothyroid muscle on the anterior neck

PURPOSE

Although anatomical variations were continuously found in the infrahyoid muscles, muscular variations of the sternothyroid muscle are still rare.

MATERIALS AND METHODS

We found an accessory belly of the sternothyroid muscle in a 46-year-old Korean male cadaver during routine dissection course, whose cause of death was 'chronic renal failure'.

RESULTS

The accessory belly attached to the oblique line of the lamina of the thyroid cartilage, covered the thyroid gland anteriorly, and attached to posterior surface of left sternothyroid muscle and pretracheal layer of the cervical fascia from side to side. It was supplied by the inferior thyroid artery from the left thyrocervical trunk and innervated by the nerve to sternothyroid muscle from the left ansa cervicalis.

CONCLUSION

The present case is worth because it requires special attention performing procedures on the anterior neck.

Silibinin Inhibits LPS-Induced Macrophage Activation by Blocking p38 MAPK in RAW 264.7 Cells

We demonstrate herein that silibinin, a polyphenolic flavonoid compound isolated from milk thistle (Silybum marianum), inhibits LPS-induced activation of macrophages and production of nitric oxide (NO) in RAW 264.7 cells. Western blot analysis showed silibinin inhibits iNOS gene expression. RT-PCR showed that silibinin inhibits iNOS, TNF-α, and IL1β. We also showed that silibinin strongly inhibits p38 MAPK phosphorylation, whereas the ERK1/2 and JNK pathways are not inhibited. The p38 MAPK inhibitor abrogated the LPS-induced nitrite production, whereas the MEK-1 inhibitor did not affect the nitrite production. A molecular modeling study proposed a binding pose for silibinin targeting the ATP binding site of p38 MAPK (1OUK). Collectively, this series of experiments indicates that silibinin inhibits macrophage activation by blocking p38 MAPK signaling.

Anterior cerebral artery aneurysm associated with multiple intracranial aneurysms and abdominal aorta aneurysm

We found multiple aneurysms in the intracranial arteries and abdominal aorta of an 87-year-old Korean female cadaver, whose cause of death was reported as "cholangiocarcinoma." An abdominal aortic aneurysm was observed in the infrarenal aorta, where the inferior mesenteric artery arose. The intracranial aneurysms were found in the A3 segment of the anterior cerebral artery and at the bifurcation of the middle cerebral artery. This case provides an example of the very rare association of peripheral intracranial aneurysms with an abdominal aortic aneurysm. Clinicians as well as anatomists should recognize the potential association between these two aneurysm types.

Apurinic/apyrimidinic endonuclease immunoreactivity in germ cells of experimental varicocele-induced rat testes

Increased germ cell apoptosis is related to oxidative DNA damage; therefore, we investigated whether there was a significant change in apurinic/apyrimidinic endonuclease (APE) in varicoceles. Experimental varicoceles were created by partial ligation of the left renal vein of adult male Sprague-Dawley rats, which were sacrificed at 1, 3 and 6 weeks after varicocele creation. Testicular tissues were sampled for TUNEL, Western blotting and immunohistochemistry. There was a significant increase in apoptotic germ cells in the ipsilateral testes 6 weeks after varicocele creation. Increased activation of p53, Bax and cleaved caspase-3 in the left testes was also noted. APE increased activation until 3 weeks after varicocele creation, and then decreased at 6 weeks after varicocele surgery. The spermatocytes were immunostained for both 8-hydroxy-2'-deoxyguanosine and APE, but the spermatogonia revealed only APE immunopositivity in the defective tubules. These results suggest that repression of APE is an underlying mechanism of augmented p53-dependent apoptosis in varicocele-induced rat testes and that remaining APE in the spermatogonia plays a decisive role in regaining testicular spermatogenic function after varicocelectomy.

Radicicol Inhibits iNOS Expression in Cytokine-Stimulated Pancreatic Beta Cells

Here, we show that radicicol, a fungal antibiotic, resulted in marked inhibition of inducible nitric oxide synthase (iNOS) transcription by the pancreatic beta cell line MIN6N8a in response to cytokine mixture (CM: TNF-α, IFN-γ, and IL-1β). Treatment of MIN6N8a cells with radicicol inhibited CM-stimulated activation of NF-κB/Rel, which plays a critical role in iNOS transcription, in a dose-related manner. Nitrite production in the presence of PD98059, a specific inhibitor of the extracellular signal-regulated protein kinase-1 and 2 (ERK1/2) pathway, was dramatically diminished, suggesting that the ERK1/2 pathway is involved in CM-induced iNOS expression. In contrast, SB203580, a specific inhibitor of p38, had no effect on nitrite generation. Collectively, this series of experiments indicates that radicicol inhibits iNOS gene expression by blocking ERK1/2 signaling. Due to the critical role that NO release plays in mediating destruction of pancreatic beta cells, the inhibitory effects of radicicol on iNOS expression suggest that radicicol may represent a useful anti-diabetic activity.

Apurinic/apyrimidinic endonuclease 1, the sensitive marker for DNA deterioration in dextran sulfate sodium-induced acute colitis

Mutations in mismatch repair (MMR) genes are commonly associated with the development of colorectal cancer. Additionally, base excision repair, which involves apurinic/apyrimidinic endonuclease 1 (APE1), recognizes and eliminates oxidative DNA damage. Here, we investigated the possible roles of APE1 in dextran sulfate sodium (DSS)-induced acute colitis using the young rat model. Four-week-old Sprague-Dawley rats were administered 2% DSS in drinking water for 1 week. MMR and APE1 expression levels were assessed by western blotting and immunohistochemistry. Following DSS treatment, growth of young rats failed and the animals had loose stools. Together with the histological changes associated with acute colitis, APE1 and MSH2 levels increased significantly at 3 and 5 days after DSS treatment, respectively. The difference between APE1 and MSH2 expression was significant. DSS-induced DNA damage and subsequent repair activity were evaluated by staining for 8-hydroxy-deoxyguanosine (8-OHdG) and APE1, respectively; 8-OHdG immunoreactivity increased throughout the colonic mucosa, while APE1 levels in the surface epithelium increased at an earlier timepoint. Taken together, our data suggest that changes in APE1 expression after DSS treatment occurred earlier and were more widespread than changes in MMR expression, suggesting that APE1 is more sensitive for prediction of DNA deterioration in DSS-induced colitis.

Colon cancer progression is driven by APEX1-mediated upregulation of Jagged

Aberrant expression of apurinic-apyrimidinic endonuclease-1 (APEX1) has been reported in numerous human solid tumors and is positively correlated with cancer progression; however, the role of APEX1 in tumor progression is poorly defined. Here, we show that APEX1 contributes to aggressive colon cancer behavior and functions as an upstream activator in the Jagged1/Notch signaling pathway. APEX1 overexpression or knockdown in human colon cancer cell lines induced profound changes in malignant properties such as cell proliferation, anchorage-independent growth, migration, invasion, and angiogenesis in vitro and in tumor formation and metastasis in mouse xenograft models. These oncogenic effects of APEX1 were mediated by the upregulation of Jagged1, a major Notch ligand. Furthermore, APEX1 expression was associated with Jagged1 in various colon cancer cell lines and in tissues from colon cancer patients. This finding identifies APEX1 as a positive regulator of Jagged1/Notch activity and suggests that it is a potential therapeutic target in colon cancers that exhibit high levels of Jagged1/Notch signaling.

Acute responses of DNA repair proteins and StarD6 in rat hippocampus after domoic acid-induced excitotoxicity

StarD6, which might be considered to be neuroprotective, and DNA repair proteins can play a role against oxidative damages by excitotoxin in the nervous system. In order to investigate the relationship between StarD6 and DNA repair proteins, excitotoxicity was induced by domoic acid in male Sprague-Dawley rats. Western blot analysis revealed transitorily elevated levels in StarD6, apurinic/apyrimidinic endonuclease (APE) and 8-oxoguanine DNA-glycosylase (Ogg1) in accord with the DNA damage marker phosphorylated H2AX. Immunohistochemistry revealed that increased intensity was transiently seen not only in the Stratum (Str.) radiatum and Str. lacunosum-moleculare with StarD6 and APE, but also in the Str. pyramidale with Ogg1. Intensities decreased 24h after domoic acid injection in CA3 with APE and Ogg1 as well as in the Str. radiatum and Str. lacunosum-moleculare with StarD6 and APE. These results suggested that StarD6 may not be closely related with DNA repair proteins in the hippocampus after domoic acid-induced excitotoxicity, although the activities of these proteins might be positively affected by excitotoxic stimuli.

Regulation of cellular RNA nano-particle assembly by splicing factor SRp20

Cellular RNA nano-particles (RNA granules) such as stress granule (SG) and P-body (PB) are translationally silenced mRNA-protein complexes. Previously, a genome-wide loss-of-function screen using oligomeric siRNAs targeting potential drug target genes was performed to identify genes that are involved in SG and PB assembly. SRp20 (SRSF3), a splicing regulator, was identified as a potential regulator for the RNA granule assembly. Here, we show that SRp20 is a bona-fide RNA granule component using antibody against SRp20 as well as Flag-tagged SRp20 through immunofluorescence microscopy. More importantly, upon knockdown of SRp20 using siRNA, RNA granule formation was potently disrupted indicating that SRp20 is one of the major structural components of SGs and PBs. Interestingly, polysome profiling analyses displayed that SRp20 is distributed in all ribosomal fractions suggesting a potential role of SRp20 as a post-transcriptional mRNA regulator. These results broaden the functional role of SRp20 from the nuclear RNA processing events to the cytoplasmic post-transcriptional mRNA regulatory events through RNA granules that are critical for the regulation of gene expression.

Synergistic Induction of iNOS by IFN-γ and Glycoprotein Isolated from Dioscorea batatas

Dioscorea species continue to be used in traditional Chinese medicine, and represent a major source of steroid precursors for conventional medicine. In the previous study, We isolated glycoprotein (GDB) from Dioscorea batatas, characterized, and demonstrated immunostimulating activity in C57BL/6 mice. The aim of this study was to investigate the mechanism whereby GDB activates macrophages. Macrophages activation by GDB was investigated by analyzing the effects of GDB on nitric oxide (NO) production, iNOS expression, mitogen activated protein kinase (MAPK) phosphorylation, and transcription factor activation. In the presence of IFN-γ, GDB strongly stimulated macrophages to express iNOS and produce NO. Furthermore, the activation of p38 was synergistically induced by GDB plus IFN-γ , but SB203580 (a p38 inhibitor) inhibited GDB plus IFN-γ-induced p38 activation. This study indicates that GDB is an important activator of macrophages. Furthermore, due to the critical role that macrophage activation plays in innate immune response, the activation effects of GDB on macrophages suggest that GDB may be a useful immunopotentiating agent.

The changes of calretinin immunoreactivity in paraquat-induced nephrotoxic rats

Calcium-binding proteins are present in the kidneys: calbindin D-28k in the distal tubules and calretinin in the proximal tubules. Since paraquat causes degeneration in the brush border-bearing proximal tubule cells in rat kidneys, we investigated the changes of calretinin immunoreactivity in the proximal tubule cells of paraquat-induced nephrotoxicity in experimental male Sprague-Dawley rats following chitosan oligosaccharide pretreatment to investigate its protective properties. Paraquat (60 mg/kg) was administered intraperitoneally with or without chitosan oligosaccharide (500 mg/kg, p.o.) pretreatment. The changes on calretinin were compared with those of calbindin D-28k by immunohistochemistry and Western Blot analysis. Calretinin was immunolocalized on the apical surface of proximal tubule cells in the deeper cortex of normal kidney, and disappeared after paraquat administration with minor changes of calbindin D-28k immunoreactivity in the distal tubules and collecting ducts. Chitosan oligosaccharide pretreatment caused increased expression of calretinin and calbindin D-28k before paraquat injection and helped preserve proximal tubules after paraquat treatment. However, Western blot analysis on calretinin and calbindin D-28k could not explain the degeneration of the proximal tubule cells in paraquat-induced nephrotoxicity. These findings suggested that calretinin is a possible and more useful histopathological marker for proximal tubule cells in paraquat-induced nephrotoxic rats.

The role of apurinic/apyrimidinic endonuclease on the progression of streptozotocin-induced diabetic nephropathy in rats

Apurinic/apyrimidinic endonuclease (APE) acts as a regulator of p53 or vice versa in the cellular response to oxidative stress. Since oxidative stress-induced apoptosis is suggested in the pathophysiology of diabetic nephropathy, we proposed that APE may have a feasible role in the progression of diabetic complications. We investigated the interrelationship between APE and p53 in streptozotocin-induced diabetic rat kidneys. Variable parameters on kidneys were checked 12 weeks after streptozotocin administration with or without chitosan oligosaccharide (COS) treatment. Streptozotocin administration caused changes as seen in early diabetic nephropathy with increased kidney size, increased p53, decreased APE, and increased cleaved caspase-3. COS was not suspected as being detrimental to renal measurements, and caused the augmentation of APE after streptozotocin administration. The augmented APE, in association with increased p53, suppressed cleaved caspase-3. 8-OHdG was mainly immunolocalized in the distal tubules, but also in the proximal tubules after streptozotocin administration without COS treatment, while APE was observed in proximal tubules in all groups. These results suggested that p53-dependent apoptosis resulting in suppressed APE might be an underlying mechanism of streptozotocin-induced nephropathy.

MEK2 regulates ribonucleotide reductase activity through functional interaction with ribonucleotide reductase small subunit p53R2

The p53R2 protein, a newly identified member of the ribonucleotide reductase family that provides nucleotides for DNA damage repair, is directly regulated by p53. We show that p53R2 is also regulated by a MEK2 (ERK kinase 2/MAP kinase kinase 2)-dependent pathway. Increased MEK1/2 phosphorylation by serum stimulation coincided with an increase in the RNR activity in U2OS and H1299 cells. The inhibition of MEK2 activity, either by treatment with a MEK inhibitor or by transfection with MEK2 siRNA, dramatically decreased the serum-stimulated RNR activity. Moreover, p53R2 siRNA, but not R2 siRNA, significantly inhibits serum-stimulated RNR activity, indicating that p53R2 is specifically regulated by a MEK2-dependent pathway. Co-immunoprecipitation analyses revealed that the MEK2 segment comprising amino acids 65-171 is critical for p53R2-MEK2 interaction, and the binding domain of MEK2 is required for MEK2-mediated increased RNR activity. Phosphorylation of MEK1/2 was greatly augmented by ionizing radiation, and RNR activity was concurrently increased. Ionizing radiation-induced RNR activity was markedly attenuated by transfection of MEK2 or p53R2 siRNA, but not R2 siRNA. These data show that MEK2 is an endogenous regulator of p53R2 and suggest that MEK2 may associate with p53R2 and upregulate its activity.

Hypoplasia of left vertebral artery with intimal fibromuscular dysplasia in a Korean woman

We found a case of hypoplasia of vertebral artery with fibromuscular dysplasia in an 82-yr-old Korean female cadaver during a routine dissection course. In the present case, intracranial hypoplasia in left vertebral artery and bilateral origin of posterior inferior cerebellar artery at the vertebrobasilar junction were recognized. Histopathologically, left vertebral artery showed intimal type of fibromuscular dysplasia both in its extracranial and intracranial courses. These results indicate that the association of fibromuscular dysplasia and hypoplasia does exist in the vertebral artery, although the etiologies are not verified yet.

A cadaveric study of needle insertion at PC6 in eight wrists of four subjects and an understanding of the anatomy

The anatomical structures vulnerable to acupuncture around the PC6 acupuncture point were investigated. Needles were inserted in PC6 of eight wrists from four cadavers to a depth of 2 cm, the forearms were dissected and the adjacent structures around the path of the needles were observed. The needles passed between the tendons of the palmaris longus and flexor carpi radialis muscles and then penetrated the flexor digitorum superficialis, flexor digitorum profundus and pronator quadratus muscles. The inserted needles were located adjacent to the median nerve. To minimise the risk of unintended injury by acupuncture, it is recommended that needles should not be inserted deeply at the PC6 acupuncture point. An understanding of the anatomical variations of the median nerve and the persistent median artery in the forearm is of clinical importance when performing acupuncture procedures.

Calretinin immunoreactivity in normal and carbon tetrachloride-induced nephrotoxic rats

Carbon tetrachloride (CCl(4)) is a potent hepatotoxic and nephrotoxic chemical. Little, however, is known about the association of CCl(4)-induced nephrotoxicity and calretinin. We hypothesized that calretinin might be localized in the proximal tubule cells and play a role against CCl(4)-induced nephrotoxicity, since the target of CCl(4) is the brush border-bearing tubule cells. CCl(4) (1 ml/kg) was administrated by oral gavage to 8-week old male Sprague-Dawley rats once a week for 4 weeks. A significant increase in serum blood urea nitrogen and creatinine was confirmed by serum analysis. Calretinin immunolocalization was compared with the calbindin D-28k immunoreactivity in normal and CCl(4)-treated kidneys. Calretinin was clearly immunolocalized in the apical surface of proximal convoluted tubule in the deeper cortex of normal kidney and blurred after CCl(4) administration, with only minor changes of calbindin D-28k immunoreactivity in the distal convoluted tubules and collecting ducts, irrelevant to the CCl(4) treatment. These findings might have significance since decreased immunolocalization of calretinin with CCl(4)-induced nephrotoxicity may contribute to the toxicity-related decrease in calcium transport or calcium buffering activity in the kidney.

Immunolocalization of steroidogenic acute regulatory protein-related lipid transfer (START) domain-containing proteins in the developing cerebellum of normal and hypothyroid rats

Cholesterol transport proteins are a prerequisite for neurosteroidogenesis. Steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domain-containing proteins, such as StAR and START domain-containing 6 (StarD6), are known to be distributed in the brain. Since perinatal hypothyroidism affects cerebellar development, we examined postnatal changes in StAR and StarD6 immunolocalization in the developing cerebellum of control and hypothyroid rats. Pregnant Sprague-Dawley rats were given 0.05% 6-propyl-2-thiouracil (PTU) or water from gestation day 11 until postnatal day (P) 28, and were then killed together with age-matched control rats. As shown by calbindin D-28k immunostaining, the developing cerebellar cytoarchitecture and Purkinje cells were affected by PTU-induced hypothyroidism as compared to control rats. The immunolocalization of StAR and StarD6 generally followed the maturation pattern of Purkinje cells from the vermis to the cerebellar hemisphere. StAR immunostaining first appeared in the Purkinje cells of the vermis at P7 in both control and hypothyroid rats. In control rats, a few StarD6 immunoreactive cells were seen at birth and a nuclear localization of StarD6 in Purkinje cells was obvious at P14. PTU-induced hypothyroidism delayed the appearance of StarD6 immunopositive cells until P7. Moreover, the nuclear localization of StarD6 in PTU-treated rats was not obvious at P14. An adult-like distribution of StAR and StarD6 was achieved by P21 in control and hypothyroid rats. These results suggest that StarD6 may affect the development of Purkinje cells during the first and second postnatal weeks, a known period of thyroid hormone action.

A case of the inferior mesenteric artery arising from the superior mesenteric artery in a Korean woman

Anatomical variations of the inferior mesenteric artery are extremely uncommon, since the inferior mesenteric artery is regularly diverged at the level of the third lumbar vertebra. We found a rare case in which the inferior mesenteric artery arose from the superior mesenteric artery. The findings were made during a routine dissection of the cadaver of an 82-yr-old Korean woman. This is the tenth report on this anomaly, the second female and the first Korean. The superior mesenteric artery normally arising from abdominal aorta sent the inferior mesenteric artery as the second branch. The longitudinal anastomosis vessels between the superior mesenteric artery and inferior mesenteric artery survived to form the common mesenteric artery. This anatomical variation concerning the common mesenteric artery is of clinical importance, performing procedures containing the superior mesenteric artery.

Does the StarD6 mark the same as the StAR in the nervous system?

Unlike steroidogenic acute regulatory protein (StAR), one of the cholesterol transport protein, little attention is given to StarD6 which belongs to a family of StAR-related lipid transfer domain proteins. Although we undertook previous works with StarD6 in the nervous system, the characteristics are in controversy to date. Therefore, we attempted to investigate the morphological characteristics of StarD6 in the nervous system are the same as StAR in vitro and in vivo. The number of immunoreactive cells was significantly different by StAR or StarD6 in the cultured glioblastoma cell lines and dopaminergic neuronal cell lines. StarD6 immunoreactivity was changed by the presence of DNA-dependent protein kinase, while the dependency was not observed in StAR immunoreactivity. Besides, StarD6 was mainly observed in the stratum pyramidale and StAR in the other strata of normal rat hippocampus proper. Increased immunolocalization of StAR and StarD6 was seen in the stratum pyramidale and the strata lacunosum-moleculare, respectively, 3h after pilocarpine-induced epilepsy. Taken together, morphological aspects of StarD6 were significantly different from those of StAR in cultured glial and neuronal cells, as well as the distribution in the normal and epileptic rat hippocampus. These results suggested that StarD6 did not mark the same as StAR in vitro and in vivo.

Long-term effects of chitosan oligosaccharide in streptozotocin-induced diabetic rats

Streptozotocin has been used to induce an experimental model for diabetes to study the activity of anti-diabetic agents. The cholesterol-lowering effect of chitosan makes a continued issue in the field of diabetes, but the hypoglyecemic effect is inconclusive to date. Unlike chitosan, the water soluble chitosan oligosaccharide may possess various biological properties for diabetes. The present study was designed to investigate the long-term effects of chitosan oligosaccharide in normal and streptozotocin-induced diabetic rats using glycated hemoglobin and C-peptide. Chitosan oligosaccharide feeding did not cause any harmful effect on plasma glucose as well as plasma lipid metabolism in normal rats, although slightly elevated triglyceride was observed. As compared with the diabetic control rats, effects of chitosan oligosaccharide for 12 weeks in the diabetic rats were summarized as follows; (1) the blood glucose concentrations fell significantly and it was confirmed by decreased glycated hemoglobin, (2) the plasma C-peptide was increased and provided elevated degree of insulin secretion, and (3) relatively well reconstructed pancreatic islet with β-cells and additional insulin-immunolabeled cells in the pancreatic acinus and in the intercalated duct were observed. These results suggested that chitosan oligosaccharide could improve the altered blood glucose metabolism in the diabetic rats by various mechanisms such as accelerated proliferation or neogenesis of β cells and increased secretory capacity of insulin.

Immunolocalization of 8-OHdG and OGG1 in pancreatic islets of streptozotocin-induced diabetic rats

This study examined whether oxidative DNA damage and its repair system contribute to the occurrence of diabetes in an experimental rat model. The changed morphological findings of the 8-hydroxydeoxyguanosine (8-OHdG) and 8-oxoG-DNA glycosylase (OGG1) were examined in the pancreatic islets in streptozotocin-induced diabetic rats (60 mg/kg, i.p.). The patterns of immunolocalization were mainly observed in the periphery of the normal pancreatic islet: 8-OHdG in the nucleus and OGG1 in the cytoplasm. The altered immunolocalization of 8-OHdG and OGG1 were greatest in the first hours after streptozotocin injection, and then declined in parallel with the morphological observations of pancreatic beta cell destruction. These results suggested that increased oxidative DNA damage might play a role as the inducer of diabetes and that OGG1 may not successfully mediate DNA repair in streptozotocin-induced diabetic rat pancreas.

Senescence-dependent MutS alpha dysfunction attenuates mismatch repair

DNA damage and mutations in the genome increase with age. To determine the potential mechanisms of senescence-dependent increases in genomic instability, we analyzed DNA mismatch repair (MMR) efficiency in young and senescent human colonic fibroblast and human embryonic lung fibroblast. It was found that MMR activity is significantly reduced in senescent cells. Western blot and immunohistochemistry analysis revealed that hMSH2 and MSH6 protein (MutS alpha complex), which is a known key component in the MMR pathway, is markedly down-regulated in senescent cells. Moreover, the addition of purified MutS alpha to extracts from senescent cells led to the restoration of MMR activity. Semiquantitative reverse transcription-PCR analysis exhibited that MSH2 mRNA level is reduced in senescent cells. In addition, a decrease in E2F transcriptional activity in senescent cells was found to be crucial for MSH2 suppression. E2F1 small interfering RNA expression reduced hMSH2 expression and MMR activity in young human primary fibroblast cells. Importantly, expression of E2F1 in quiescent cells restored the MSH2 expression as well as MMR activity, whereas E2F1-infected senescent cells exhibited no restoration of MSH2 expression and MMR activity. These results indicate that the suppression of E2F1 transcriptional activity in senescent cells lead to stable repression of MSH2, followed by a induction of MutS alpha dysfunction, which results in a reduced cellular MMR capacity in senescent cells.

Human 8-oxoguanine DNA glycosylase suppresses the oxidative stress induced apoptosis through a p53-mediated signaling pathway in human fibroblasts

Human 8-oxoguanine DNA glycosylase (hOGG1) is the main defense enzyme against mutagenic effects of cellular 7,8-dihydro-8-oxoguanine. In this study, we investigated the biological role of hOGG1 in DNA damage-related apoptosis induced by hydrogen peroxide (H(2)O(2))-derived oxidative stress. The down-regulated expression of hOGG1 by its small interfering RNA prominently triggers the H(2)O(2)-induced apoptosis in human fibroblasts GM00637 and human lung carcinoma H1299 cells via the p53-mediated apoptotic pathway. However, the apoptotic responses were specifically inhibited by hOGG1 overexpression. The p53-small interfering RNA transfection into the hOGG1-deficient GM00637 markedly inhibited the H(2)O(2)-induced activation of p53-downstream target proteins such as p21, Noxa, and caspase-3/7, which eventually resulted in the increased cell viability. Although the cell viability of hOGG1-knockdown H1299 p53 null cells was similar to that of the hOGG1 wild-type H1299, after the overexpression of p53 the hOGG1-knockdown H1299 showed the significantly decreased cell viability compared with that of the hOGG1 wild-type H1299 at the same experimental condition. Moreover, the array comparative genome hybridization analyses revealed that the hOGG1-deficient GM00637 showed more significant changes in the copy number of large regions of their chromosomes in response to H(2)O(2) treatment. Therefore, we suggest that although p53 is a major modulator of apoptosis, hOGG1 also plays a pivotal role in protecting cells against the H(2)O(2)-induced apoptosis at the upstream of the p53-dependent pathway to confer a survival advantage to human fibroblasts and human lung carcinomas through maintaining their genomic stability.

Immunohistochemical detection of StarD6 in the rat nervous system

Steroidogenic acute regulatory (StAR)-related lipid transfer (START) domain 6 (StarD6) is known to be exclusively expressed in germ cells of testis. As little is known about StarD6 expression in the nervous system, we investigated the distribution of StarD6 in rat neural tissues. Immunoreactivity of StarD6 was detected in the brain, spinal cord and dorsal root ganglia; particularly cerebral cortex (layer V and VI), hippocampus, substantia gelatinosa of the spinal cord. We provided compelling evidence that multiple neuronal and glial populations were immunolabelled with anti-StarD6 antibody throughout the nervous system. We postulate that StarD6 might play an important role in lipid sensing of the nervous system based on its immunolocalization in this study.