Chromatinization Modulates Topoisomerase II Processivity.

Type IIA topoisomerases are essential DNA processing enzymes that must robustly and reliably relax DNA torsional stress in vivo. While cellular processes constantly create different degrees of torsional stress, how this stress feeds back to control type IIA topoisomerase function remains obscure. Using a suite of single-molecule approaches, we examined the torsional impact on supercoiling relaxation of both naked DNA and chromatin by eukaryotic topoisomerase II (topo II). We observed that topo II was at least ~ 50-fold more processive on plectonemic DNA than previously estimated, capable of relaxing > 6000 turns. We further discovered that topo II could relax supercoiled DNA prior to plectoneme formation, but with a ~100-fold reduction in processivity; strikingly, the relaxation rate in this regime decreased with diminishing torsion in a manner consistent with the capture of transient DNA loops by topo II. Chromatinization preserved the high processivity of the enzyme under high torsional stress. Interestingly, topo II was still highly processive (~ 1000 turns) even under low torsional stress, consistent with the predisposition of chromatin to readily form DNA crossings. This work establishes that chromatin is a major stimulant of topo II function, capable of enhancing function even under low torsional stress.

Chromatinization modulates topoisomerase II processivity.

Type IIA topoisomerases are essential DNA processing enzymes that must robustly and reliably relax DNA torsional stress. While cellular processes constantly create varying torsional stress, how this variation impacts type IIA topoisomerase function remains obscure. Using multiple single-molecule approaches, we examined the torsional dependence of eukaryotic topoisomerase II (topo II) activity on naked DNA and chromatin. We observed that topo II is ~50-fold more processive on buckled DNA than previously estimated. We further discovered that topo II relaxes supercoiled DNA prior to plectoneme formation, but with processivity reduced by ~100-fold. This relaxation decreases with diminishing torsion, consistent with topo II capturing transient DNA loops. Topo II retains high processivity on buckled chromatin (~10,000 turns) and becomes highly processive even on chromatin under low torsional stress (~1000 turns), consistent with chromatin's predisposition to readily form DNA crossings. This work establishes that chromatin is a major stimulant of topo II function.

Retraction: Sasa borealis extract exerts an antidiabetic effect via activation of the AMP-activated protein kinase.

[This retracts the article on p. 15 in vol. 7, PMID: 23423690.].

Moxibustion as an adjunct for lower urinary tract symptoms associated with benign prostate enlargement: A randomized controlled pilot trial.

BACKGROUND: Benign prostatic enlargement (BPE) causes discomfort in daily life, including lower urinary tract symptoms (LUTSs) caused by the enlarged prostate, and requires long-term management as a chronic, irreversible disease. To improve LUTS, certain complementary therapies have been used with or without doctors' directions. Conventional treatments and complementary therapies tend to be combined unsystematically, depending on patient preference; thus, research for safe and efficient combination therapy is warranted. METHODS: Twenty-nine participants were randomly assigned to an integrative group (IG, n = 15) or a conventional group (CG, n = 14). The IG received moxibustion (twice weekly for 4 weeks, at the acupuncture points SP6, LR3, and CV4) and conventional medication for 4 weeks, followed by conventional medication alone for 8 weeks. The CG received conventional medication alone for 12 weeks. The outcome measures were International Prostate Symptom Score (IPSS), patient's global impression of changes (PGIC), maximum urinary flow rate (Qmax), postvoid residual urine volume (PVR), and frequency-volume chart. RESULTS: Total IPSS (IG, -2.4 ±â€Š4.2; CG, 0.9 ±â€Š4.0; P = .039), PGIC-A (IG, 3.5 ±â€Š1.0; CG, 2.2 ±â€Š1.0; P = .001), and PGIC-B (IG, 3.5 ±â€Š0.1; CG, 4.7 ±â€Š0.6; P = .004) were significantly improved in the IG compared with the CG, 4 weeks after baseline. Among the IPSS items, incomplete emptying (IG, -0.6 ±â€Š0.7; CG, 0.4 ±â€Š1.2; P = .019), straining (IG, -0.6 ±â€Š0.8; CG, 0.2 ±â€Š1.2; P = .046), and nocturia (IG, -0.8 ±â€Š1.4; CG, 0.1 ±â€Š1.0; P = .045) showed significant differences. The Qmax and PVR volume did not differ significantly at 12 weeks after the baseline. CONCLUSION: Moxibustion can be considered an adjunct therapy to improve LUTS in BPE patients. A full-sized randomized controlled trial would be feasible with comparator modifications and an extended study period. The study design should include a placebo group and narrow the eligibility to subjects who do not respond well to conventional treatments.

Synergistic Coordination of Chromatin Torsional Mechanics and Topoisomerase Activity.

DNA replication in eukaryotes generates DNA supercoiling, which may intertwine (braid) daughter chromatin fibers to form precatenanes, posing topological challenges during chromosome segregation. The mechanisms that limit precatenane formation remain unclear. By making direct torque measurements, we demonstrate that the intrinsic mechanical properties of chromatin play a fundamental role in dictating precatenane formation and regulating chromatin topology. Whereas a single chromatin fiber is torsionally soft, a braided fiber is torsionally stiff, indicating that supercoiling on chromatin substrates is preferentially directed in front of the fork during replication. We further show that topoisomerase II relaxation displays a strong preference for a single chromatin fiber over a braided fiber. These results suggest a synergistic coordination-the mechanical properties of chromatin inherently suppress precatenane formation during replication elongation by driving DNA supercoiling ahead of the fork, where supercoiling is more efficiently removed by topoisomerase II. VIDEO ABSTRACT.

Effectiveness and safety of moxibustion for alleviating symptoms of overactive bladder: A prospective, randomized controlled, crossover-design, pilot study.

BACKGROUND: This study aimed to evaluate trial feasibility and explore the potential efficacy and safety of moxibustion in the treatment of overactive bladder (OAB). METHOD: A randomized, controlled, cross-over, assessor blinded design was used. This study was conducted in an outpatient department of a university hospital in Republic of Korea. The overall study period was 8 weeks. Participants were randomly allotted to either Group A or Group B. Group A participants underwent 8 to 12 sessions of moxibustion with behavioral training during the first 4 weeks, while the Group B participants received behavioral training only. Over the next 4 weeks, the treatment offered to the 2 groups was reversed (Group A participants received behavioral training only, while Group B participants underwent the moxibustion session with behavioral training). The OAB-validated 8-question awareness tool (OAB-V8), OAB symptom scores (OABSS), visual analog scale (VAS) for lower urinary tract symptoms, and frequency voiding chart were used to assess outcomes. For analysis, we used effect size, measured as Hedge's g, to present descriptive results indicating the actual difference between the groups. RESULTS: Compared to that in Group B, the Hedge's g of OAB-V8 for the former 4 weeks in Group A was -0.248, that of OABSS was -1.531, and that of VAS was -0.713. During the latter 4 weeks, Group B showed similar effect with g = 0.465, 1.207, and 0.427 for OAB-V8, OABSS, and VAS, respectively, compared to Group A. The portion of nocturnal voiding volume decreased (g = -0965), the mean voiding volume increased (g = 0.690), and the voiding frequency decreased (g = -0.498) with moxibustion. CONCLUSIONS: Moxibustion might be considered as an alternative for OAB. A full-sized randomized controlled trial may be feasible with minimal modification in outcome measures and comparator population. OTHER INFORMATION: This clinical trial has been registered on clinicaltrials.gov (NCT02271607).

Moxibustion as an adjuvant for benign prostatic hyperplasia with lower urinary tract symptoms: a protocol for a parallel-group, randomised, controlled pilot trial.

INTRODUCTION: This study aims to explore the feasibility of using moxibustion as a supplementary intervention and to assess the sample size for verifying the effectiveness and safety of integrative treatment involving moxibustion compared with conventional treatment for patients with benign prostatic hyperplasia accompanying moderate to severe lower urinary tract symptoms. METHODS AND ANALYSIS: A total of 60 patients diagnosed with benign prostatic hyperplasia by a urologist based on prostate size, prostate-specific antigen and clinical symptoms will participate of their own free will; urologists will monitor the patients and evaluate their symptoms. The patients will be randomised to either a conventional group or an integrative group with a 1:1 allocation according to computer-generated random numbers concealed in opaque, sealed, sequentially numbered envelopes. Watchful waiting or oral medication including α blocker, 5α-reductase inhibitors or antimuscarinic drugs will be offered as conventional treatment. Integrative treatment will include moxibustion therapy in addition to the conventional treatment. The moxibustion therapy will be conducted twice a week for 4 weeks on the bilateral acupoints SP6, LR3 and CV4 by a qualified Korean medical doctor. The primary outcome will be the International Prostate Symptom Score (IPSS) after eight sessions. The secondary outcomes will be the post-void residual urine volume, the maximum urinary flow rate, IPSS, the results of a Short-Form 36-Question Health Survey after 12 weeks, and the patients' global impression of changes at each visit. ETHICS AND DISSEMINATION: Written informed consent will be obtained from all participants. This study was approved by the institutional review boards of both Pusan National University Yangsan Hospital and Pusan National University Korean Medicine Hospital. The trial results will be disseminated through open-access journals and conferences. TRIAL REGISTRATION NUMBER: NCT02051036.

Sasa borealis extract exerts an antidiabetic effect via activation of the AMP-activated protein kinase.

Leaf of Sasa borealis, a species of bamboo, has been reported to exhibit anti-hyperglycemic effect. However, its antidiabetic mechanism is not fully understood. In this study, we examined whether an extract of S. borealis activates AMP-activated protein kinase (AMPK) and exerts anti-hyperglycemic effects. Treatment with the S. borealis extract increased insulin signaling and phosphorylation of AMPK and stimulated the expression of its downstream targets, including PPARα, ACO, and CPT-1 in C2C12 cells and PPARα in HepG2 cells. However, inhibition of AMPK activation attenuated insulin signaling and prevented the stimulation of AMPK target genes. The S. borealis extract increased glucose uptake in C2C12 cells and suppressed expression of the gluconeogenic gene, PEPCK in HepG2 cells. The extract significantly reduced blood glucose and triglyceride levels in STZ-induced diabetic mice. The extract enhanced AMPK phosphorylation and increased Glut-4 expression in the skeletal muscle of the mice. These findings demonstrated that the S. borealis extract exerts its anti-hyperglycemic effect through activation of AMPK and enhancement of insulin signaling.