[Periodic dynamic observation and analysis of cellular and humoral immunity indexes of adults infected with Omicron BA.1]

Objective: To analyze the immunological characteristics and antibody changes of patients infected with the Omicron BA.1 and evaluate the possibility of secondary infection. Methods: A total of 104 patients infected with Omicron BA.1 in the Jinnan District of Tianjin from January 8 to February 2, 2022, were included in the study. The control group and case group were matched 1∶1 based on age, sex and vaccination status. Serum was collected from the case group and control group at 3, 6 and 9 months after infection. The serum levels of interleukin4 (IL-4), IL-5 and interferon-gamma (IFN-γ), as well as the positive rates of IgG, IgG1 and IgG2, were detected by ELISA. Results: The highest concentration of IFN-γ in the case group at 6 months after infection was 145.4 pg/ml, followed by a decrease in concentration. The concentrations of IL-4 and IL-5 began to decrease at 6 months after infection (all P<0.001). There was no significant difference in the IgG2 positive rate between the case group and the control group at 6 months after BA.1 infection. However, at 9 months, there was a significant decrease compared to the control group (P=0.003). The ratio of IFN-γ/IL4 at 3 months after infection in the case group was lower than that in the control group (P<0.001). There was no significant difference in the ratio between the case group and the control group at 9 months after infection. Conclusion: The cellular immune function has been impaired at 3 months after infection with BA.1, and the specific cellular immune and humoral immune functions decrease significantly after 6 months, and the risk of secondary infection increases.

Mechanism of target site selection by type V-K CRISPR-associated transposases

CRISPR-associated transposases (CASTs) repurpose nuclease-deficient CRISPR effectors to catalyze RNA-guided transposition of large genetic payloads. Type V-K CASTs offer potential technology advantages but lack accuracy, and the molecular basis for this drawback has remained elusive. Here, we reveal that type V-K CASTs maintain an RNA-independent, "untargeted" transposition pathway alongside RNA-dependent integration, driven by the local availability of TnsC filaments. Using cryo-electron microscopy, single-molecule experiments, and high-throughput sequencing, we found that a minimal, CRISPR-less transpososome preferentially directs untargeted integration at AT-rich sites, with additional local specificity imparted by TnsB. By exploiting this knowledge, we suppressed untargeted transposition and increased type V-K CAST specificity up to 98.1% in cells without compromising on-target integration efficiency. These findings will inform further engineering of CAST systems for accurate, kilobase-scale genome engineering applications.

Dietary cholecalciferol and 25-hydroxycholecalciferol supplementation interact to modulate reproductive performance, egg quality, serum antioxidant capacity, intestinal morphology and tibia quality of breeder geese

1. A study was conducted to evaluate the effects of dietary cholecalciferol (vitamin D3) and 25-hydroxycholecalciferol (25-OH-D3) supplementation on the reproductive performance, egg quality, eggshell ultrastructure, serum hormone level and antioxidant capacity, intestinal morphology and tibia quality of breeder geese during the laying period.2. The trial was designed as a 3 × 3 factorial arrangement with three levels (300, 400 and 500 IU/kg) of vitamin D3 supplementation and three levels (25, 50 and 75 μg/kg) of 25-OH-D3 supplementation in a 10-wk feeding trial.3. The results showed that the combined supplementation of 400 IU/kg vitamin D3 and 50 μg/kg 25-OH-D3 had a better feed conversion ratio and a higher egg laying rate than the other groups. Vitamin D3 supplementation significantly increased the rate of qualified eggs for hatching, eggshell strength and thickness, serum testosterone and progesterone levels, serum total superoxide dismutase and glutathione peroxidase activities, tibia ash content and bone mineral density (P < 0.05). Dietary 25-OH-D3 supplementation significantly increased serum glutathione peroxidase activity and duodenal villus height and villus height-to-crypt-depth ratio (P < 0.05). The geese receiving 500 IU/kg vitamin D3 and 75 µg/kg 25-OH-D3 had the highest tibia calcium and phosphorous content among all groups (P < 0.05).4. Feeding 400 IU/kg vitamin D3 plus 50 µg/kg 25-OH-D3 gave optimal effects on feed conversion ratio and egg laying rate. This combination could be a nutritional strategy for increasing the laying rate, eggshell quality, serum hormone levels and serum antioxidant function regardless of 25-OH-D3 supplementation. Supplementation of 50 μg/kg 25-OH-D3 could be a recommended dose for improving the serum antioxidant capacity and intestinal morphology regardless of vitamin D3 supplementation.

Mechanism of target site selection by type V-K CRISPR-associated transposases

Unlike canonical CRISPR-Cas systems that rely on RNA-guided nucleases for target cleavage, CRISPR-associated transposases (CASTs) repurpose nuclease-deficient CRISPR effectors to facilitate RNA-guided transposition of large genetic payloads. Type V-K CASTs offer several potential upsides for genome engineering, due to their compact size, easy programmability, and unidirectional integration. However, these systems are substantially less accurate than type I-F CASTs, and the molecular basis for this difference has remained elusive. Here we reveal that type V-K CASTs undergo two distinct mobilization pathways with remarkably different specificities: RNA-dependent and RNA-independent transposition. Whereas RNA-dependent transposition relies on Cas12k for accurate target selection, RNA-independent integration events are untargeted and primarily driven by the local availability of TnsC filaments. The cryo-EM structure of the untargeted complex reveals a TnsB-TnsC-TniQ transpososome that encompasses two turns of a TnsC filament and otherwise resembles major architectural aspects of the Cas12k-containing transpososome. Using single-molecule experiments and genome-wide meta-analyses, we found that AT-rich sites are preferred substrates for untargeted transposition and that the TnsB transposase also imparts local specificity, which collectively determine the precise insertion site. Knowledge of these motifs allowed us to direct untargeted transposition events to specific hotspot regions of a plasmid. Finally, by exploiting TnsB's preference for on-target integration and modulating the availability of TnsC, we suppressed RNA-independent transposition events and increased type V-K CAST specificity up to 98.1%, without compromising the efficiency of on-target integration. Collectively, our results reveal the importance of dissecting target site selection mechanisms and highlight new opportunities to leverage CAST systems for accurate, kilobase-scale genome engineering applications.

[Clinical observation of bow-tie adjustable suture technique for overcorrection in intermittent exotropia]

Objective: To investigate the clinical effects of the bow-tie adjustable suture technique in managing overcorrection in patients with intermittent exotropia after surgery. Methods: This was a retrospective case series study. Clinical data were collected from children with intermittent exotropia who underwent strabismus correction surgery, including the bow-tie adjustable suture technique and conventional techniques, at the Department of Strabismus and Pediatric Ophthalmology, Shanxi Eye Hospital, from January 2020 to September 2021. Children with postoperative esodeviation≥15 prism diopters (PD) within the first 6 days were treated differently based on the surgical technique and their individual conditions, including suture adjustment and conservative treatment. The overcorrection rate and its changes among different surgical groups, the recovery of ocular alignment and binocular visual function after different treatment methods in children with overcorrection on the sixth postoperative day, and the postoperative complications in different surgical groups were observed. Statistical analysis was performed using independent samples t-test, Wilcoxon rank-sum test, repeated-measures analysis of variance, Bonferroni test, chi-square test, or Fisher's exact probability test, as appropriate. Results: A total of 643 children who underwent intermittent exotropia correction surgery were included in the study. Among them, 325 children underwent the bow-tie adjustable suture technique, with 185 males and 140 females, and the mean age was (9.50±2.69) years. The remaining 318 children underwent conventional techniques, with 176 males and 142 females, and the mean age was (9.90±2.67) years. There were no statistically significant differences in age and gender distribution between the two surgical groups (all P>0.05). On the first postoperative day, among children who underwent the bow-tie adjustable suture technique, 40 had an esodeviation of≥10 PD, resulting in an overcorrection rate of 12.3% (40/325), while among children who underwent conventional techniques, 32 had an esodeviation of≥10 PD, resulting in an overcorrection rate of 10.1% (32/318). On the sixth postoperative day, these rates decreased to 5.5% (18/325) and 3.1% (10/318) in the two groups, respectively. At 1, 6, and 12 months postoperatively, the overcorrection rate in children who underwent the bow-tie adjustable suture technique was 0, while in children who underwent conventional techniques, the overcorrection rate did not show a significant decrease compared to before surgery. The differences between the two surgical groups were statistically significant (all P<0.05). On the sixth postoperative day, among children with an esodeviation of≥15 PD, 13 underwent suture adjustment and 7 received conservative treatment. The results of repeated-measures analysis of variance showed statistically significant differences in near and distance esodeviation angles among children who received different treatment methods (F=145.20, 106.87, both P<0.001), as well as statistically significant differences in near and distance esodeviation angles at different time points within each group of children (F=81.67, 35.09, both P<0.001). There were also significant differences in the trends of change in near and distance esodeviation angles at different time points among children who received different treatment methods (F=79.90, 36.73, both P<0.001). Further pairwise comparisons showed significant differences in near and distance esodeviation angles between the sixth postoperative day and 1, 6, and 12 months postoperatively in children who underwent suture adjustment (all P<0.05), while no statistically significant differences were observed in children who received conservative treatment (all P>0.05). At 12 months postoperatively, among the 13 children who underwent suture adjustment, 12 achieved stereopsis, while among the 7 children who received conservative treatment, all became stereo-blind after removing the prismatic correction. No serious complications occurred in any of the children postoperatively. Conclusion: The proportion of children with intermittent exotropia who achieved orthotropic alignment one year after surgery was relatively low among those who had an overcorrection of≥15 PD on the sixth postoperative day. The bow-tie adjustable suture technique is a simple and effective approach for managing overcorrection in patients with intermittent exotropia. Adjusting the sutures on the sixth postoperative day can reduce the overcorrection rate and is considered a safe and effective method.

Impact of human coronavirus infections on paediatric patients at a tertiary paediatric hospital: a retrospective study of the prepandemic era

BACKGROUND

Human coronaviruses (HCoVs) are important respiratory pathogens in humans and animals. Most HCoVs are emerging pathogens, with five known human pathogens identified in the last two decades.

AIM

To examine the clinical course of HCoV infection in children to improve understanding of severity and outcomes.

METHODS

A retrospective review was undertaken of all encounters of children with known HCoV infection at a tertiary paediatric hospital from January 2015 to January 2018. Electronic medical records were reviewed for demographic data, HCoV type, viral co-pathogens, time to testing, need for hospitalization, requirement for higher-level care (HLC) including intensive care unit management and requirement for oxygen support, radiographic findings suggestive of lower respiratory tract (LRT) disease, and length of stay (LOS).

FINDINGS

In total, 450 encounters for 430 different patients were identified, with the majority (85%) being inpatient. OC43 was the most common HCoV. Younger patients (age <5 years) had higher probability of hospitalization [adjusted odds ratio (aOR) 2.2, 95% confidence interval (CI) 1.2-4.1], requirement for HLC (aOR 1.8, 95% CI 1.0-3.1) and presence of LRT findings on chest radiographs (aOR 1.7, 95% CI 1.01-2.9). Clinical outcomes did not differ between HCoV types, except LOS which was longer for 229E. Fifty-two (11%) encounters were detected after 3 days of hospitalization (median 25.5 days), suggesting possible nosocomial infection.

CONCLUSION

HCoVs are important respiratory pathogens in the paediatric population, especially among patients aged <5 years who are at increased risk for severe disease. The role of HCoVs as hospital-acquired pathogens may be underappreciated.

Repair of mismatched templates during Rad51-dependent Break-Induced Replication

Using budding yeast, we have studied Rad51-dependent break-induced replication (BIR), where the invading 3’ end of a site-specific double-strand break (DSB) and a donor template share 108 bp of homology that can be easily altered. BIR still occurs about 10% as often when every 6^th base is mismatched as with a perfectly matched donor. Here we explore the tolerance of mismatches in more detail, by examining donor templates that each carry 10 mismatches, each with different spatial arrangements. Although 2 of the 6 arrangements we tested were nearly as efficient as the evenly-spaced reference, 4 were significantly less efficient. A donor with all 10 mismatches clustered at the 3’ invading end of the DSB was not impaired compared to arrangements where mismatches were clustered at the 5’ end. Our data suggest that the efficiency of strand invasion is principally dictated by thermodynamic considerations, i.e., by the total number of base pairs that can be formed; but mismatch position-specific effects are also important. We also addressed an apparent difference between in vitro and in vivo strand exchange assays, where in vitro studies had suggested that at a single contiguous stretch of 8 consecutive bases was needed to be paired for stable strand pairing, while in vivo assays using 108-bp substrates found significant recombination even when every 6^th base was mismatched. Now, using substrates of either 90 or 108 nt–the latter being the size of the in vivo templates–we find that in vitro D-loop results are very similar to the in vivo results. However, there are still notable differences between in vivo and in vitro assays that are especially evident with unevenly-distributed mismatches. Mismatches in the donor template are incorporated into the BIR product in a strongly polar fashion up to ~40 nucleotides from the 3’ end. Mismatch incorporation depends on the 3’→ 5’ proofreading exonuclease activity of DNA polymerase δ, with little contribution from Msh2/Mlh1 mismatch repair proteins, or from Rad1-Rad10 flap nuclease or the Mph1 helicase. Surprisingly, the probability of a mismatch 27 nt from the 3’ end being replaced by donor sequence was the same whether the preceding 26 nucleotides were mismatched every 6^th base or fully homologous. These data suggest that DNA polymerase δ “chews back” the 3’ end of the invading strand without any mismatch-dependent cues from the strand invasion structure. However, there appears to be an alternative way to incorporate a mismatch at the first base at the 3’ end of the donor.

DNA double-strand breaks (DSBs) are the most lethal forms of DNA damage and inaccurate repair of these breaks presents a serious threat to genomic integrity and cell viability. Break-induced replication (BIR) is a homologous recombination pathway that results in a nonreciprocal translocation of chromosome ends. We used budding yeast Saccharomyces cerevisiae to investigate Rad51-mediated BIR, where the invading 3’ end of the DSB and a donor template share 108 bp of homology. We examined the tolerance of differently distributed mismatches on a homologous donor template. A donor with all 10 mismatches clustered every 6^th base at the 3’ invading end of the DSB was not impaired compared to arrangements where mismatches were clustered at the 5’ end. We also compared the efficiency of in vivo BIR with in vitro D-loop formation and find that for substrates of the same length, the tolerance for mismatches is comparable. However, there are still notable differences between in vivo and in vitro assays that are especially evident in substrates with unevenly-distributed mismatches. Mismatches are incorporated into the BIR product in a strongly polar fashion as far as about 40 nucleotides from the 3’ end, dependent on the 5’ to 3’ proofreading activity of DNA polymerase δ. Pol δ can “chew back” the 3’ end of the invading strand even when the sequences removed have no mismatches for the first 26 nucleotides. However, a mismatch at the first base can be removed from the 3’ end by another, unidentified mechanism.

Left atrial anatomical variations correlate with atrial fibrillation sources near the left atrial ridge

Funding Acknowledgements

Type of funding sources: None.

Background

Anatomical variations and characteristics of the left atrium (LA) may have a previously undescribed effect on source locations in atrial fibrillation (AF). Electrographic flow (EGF) mapping is a novel method used to estimate cardiac action potential flow in the atria that can detect AF sources in patients with persistent AF. The EGF technology offers a revolutionary mapping possibility for AF, however, it is not commercially available yet.

Purpose

This is the first study aiming to investigate the relationship between anatomical characteristics of the LA and non-PV sources detected by EGF in patients with persistent AF.

Methods

We collected cardiac computed tomography (CT) and EGF data from patients who underwent radiofrequency catheter ablation (CA) for persistent AF. EGF mapping creates a spatial and temporal reconstruction of electric potentials derived from endocardial unipolar electrograms. By analyzing EGF maps obtained during CA procedures, we localized non-PV sources in the LA. Patients with individual stable sources with a source activity above threshold (leading source present in more than &gt; 26% of the time) were classified as having an S-Type EGF signature with source-dependent AF. Patients with no stable active source pattern and no leading source with a source activity above threshold were characterized as having a C-Type EGF signature consistent with source-independent AF. We assessed LA anatomical characteristics including size, LAA length, LAA ostial diameter, trajectory of the left superior pulmonary vein (LSPV) and its relation to the LAA on cardiac CT scans. Abutting LAA-LSPV was defined as cases when the LSPV touched the posterior aspect of LAA, and the maximal distance between the two structures was less than 2 mm. Those cases where the distance between LAA and LSPV was more than 2 mm were defined as non-abutting LAA-LSPV.

Results

Thirty patients were included in this study (mean age 62.4±6.8 years):23 patients had an S-Type EGF signature (77%), and 7 patients had a C-Type EGF signature (23%). We identified 10 patients with AF sources near the LA ridge, while twenty patients had no leading source near the LA ridge. LA anatomical characteristics, LAA length and ostial diameter showed no correlation with the presence of a leading source near the ridge. We described 19 patients with abutting LAA-LSPV, and 11 patients with non-abutting LAA-LSPV. Three out of 19 patients presented with a leading source near ridge in the abutting LAA-LSPV group, while 7 out of 11 patients presented with a leading source near ridge in the non-abutting LAA-LSPV group (p=0.01).

Conclusion

Our data suggests that non-abutting LAA-LSPV is associated with the presence of AF sources near the LA ridge.

Use of a neural network to generate a whole atrium 3D reconstruction of electrographic flow and basket catheter geometry from biosignals alone

Funding Acknowledgements

Type of funding sources: None.

Background

Electrographic flow (EGF) mapping detects and quantifies patterns of electrical wavefront propagation in the atrial myocardium from basket catheter recordings. However, no single catheter can map the entire endocardial surface simultaneously. Creating panoramic maps of the whole atrium may be possible by reconstructing multiple basket positions obtained within a few minutes of each other.

Purpose

Present a method of 3D reconstruction of EGF maps generated from individual basket recordings using QRS morphologies and CT anatomies.

Methods

EGF maps were generated from unipolar signals recorded over 1 minute from 64-pole basket catheters. QRS morphologies recorded by each individual electrode were used to train a neural network (NN) on the reconstruction of the basket geometries in 3D. The NN uses the similarities between QRS morphologies to represent multiple recordings in one coherent 3D space and spatially integrate phenomena across multiple recordings without any external navigation system.

Results

A basket catheter was placed in the superior vena cava of a chronic AF canine model. The catheter was manually pulled back in steps of 5mm under fluoroscopic supervision. After reconstruction of the 3D electrode positions, a successive displacement of 3.5±1.2mm per step was reproduced. We applied the proposed method on recordings of 18 patients where an EGF source was identified. Independently, an expert determined the source locations on a 3rd party navigation system, based on 10 predefined regions in the left atrium. In 83% of the cases, the proposed method projected the sources in the same or adjacent region.

Conclusion

Novel 3D reconstruction from QRS signatures enables integration of EGF maps from multiple basket recordings that can be aligned with CT anatomy. Due to the real-time EGF map acquisition, synthesizing maps from more than 1 basket position provides a more panoramic visualization of complex atrial flow patterns.

[Short-term outcomes of prism treatment in a manner of reducing prism diopters step by step for small-angle acute acquired concomitant esotropia]

Objective: To investigate the short-term efficacy of the prism treatment in a manner of reducing prism diopters step by step for small-angle acute acquired concomitant esotropia (AACE). Methods: Retrospective case series study. The clinical data of 17 AACE patients with strabismus ≤25 prism degrees (PD) including 6 males and 11 females, aged 14 to 60 years, who underwent the prism treatment in the Strabismus and Pediatric Ophthalmology Clinic of Shanxi Eye Hospital from October 2018 to June 2020 were collected. The prism treatment was conducted by a step-by-step reduction of prism diopters. An under-corrected prism was applied to the patient for the first time, and the degree of the prism was reduced gradually with the decrease in the degree of strabismus. Statistical analysis was performed after 6 months of treatment. The treatment success was defined as obtaining orthotropia and deleting diplopia when prism glasses were weaned off. The strabismus degree, Worth 4 dot test results, near stereopsis (Titmus stereopsis) and synoptophore fusion function before and after treatment were compared, and the factors affecting the curative effect were analyzed. Statistical methods mainly included paired t-test, Wilcoxon rank sum test, the Fisher exact test and univariate logistic regression analysis. Results: Among these 17 patients, 15 had myopia and 2 had emmetropia. Pretherapeutic esodeviation was (13.94±5.83) PD at near (33 cm), and was (15.76±5.24) PD at distance (6 m). After 6 months of treatment, 7 patients were successfully cured. The deviation angle at distance [(10.60±7.16) PD] and near [(9.80±6.00) PD] of the remaining 10 patients at 6 months after prismatic treatment was significantly smaller than that before treatment [(17.50±5.40) PD and (16.10±5.47) PD; t=3.69, 4.10; both P<0.01]. The Titmus stereogram showed that 2 cases had no stereopsis, 6 cases had peripheral stereopsis, 3 cases had macular stereopsis, and 6 cases had foveal stereopsis before treatment. Stereopsis was significantly improved at 6 months after prismatic treatment, with 3 cases havimg macular stereopsis and 14 cases having foveal stereopsis (Z=-2.99; P<0.01). The Worth-4-dot test disclosed that, the number of patients who saw four lamps at distance and near was 0 and 2 before treatment, and 7 and 9 after treatment, respectively, and the difference was statistically significant (both P<0.05). The divergent fusional amplitude and convergent fusional amplitude in the synoptophore at 6 month after treatment was not significantly different from that before treatment (both P>0.05). The efficacy of treatment was not significantly related to the duration from onset to treatment, the pretherapeutic esodeviation, the Titmus stereoacuity, cycloplegic refractive error, and age (all P>0.05). None of the 7 patients, who were successfully cured had a recurrence of esotropia or diplopia during the observation period of 6 to 24 months (median, 11 months). Conclusions: Prism treatment in a manner of step-by-step reduction of prism diopters can significantly diminish the degree of esotropia and improve the binocular function in small-angle AACE. Furthermore, some patients could be cured, achieving orthophoria without diplopia.

Mechanistic Insights From Single-Molecule Studies of Repair of Double Strand Breaks

DNA double strand breaks (DSBs) are among some of the most deleterious forms of DNA damage. Left unrepaired, they are detrimental to genome stability, leading to high risk of cancer. Two major mechanisms are responsible for the repair of DSBs, homologous recombination (HR) and nonhomologous end joining (NHEJ). The complex nature of both pathways, involving a myriad of protein factors functioning in a highly coordinated manner at distinct stages of repair, lend themselves to detailed mechanistic studies using the latest single-molecule techniques. In avoiding ensemble averaging effects inherent to traditional biochemical or genetic methods, single-molecule studies have painted an increasingly detailed picture for every step of the DSB repair processes.

Single-cell RNA-seq analysis identifies unique chondrocyte subsets and reveals involvement of ferroptosis in human intervertebral disc degeneration

OBJECTIVE

Nucleus pulposus (NP) plays a central role in disc degeneration pathogenesis, however, as a heterogeneous tissue, cell subsets in NP and their corresponding biological process in intervertebral disc degeneration (IVDD) are unreported.

METHOD

Nucleus pulposus were isolated from normal control and IVDD, and then subjected to single-cell RNA sequencing (scRNA-seq). Unsupervised clustering of the cells based on the gene expression profiles using the Seurat package and passed to tSNE for clustering visualization. Rat model of disc degeneration was built to validate the pathways identified by scRNA-Seq.

RESULTS

Seven chondrocyte subsets were revealed in NP based on differential gene expression, among which 4 subsets (C1-C4) were reported for the first time. Furthermore, GO and KEGG analyses discovered that ferroptosis pathways were enriched. Rat model of disc degeneration was built (n = 6/group, control vs. model) to validate the pathways identified by scRNA-Seq. Iron levels of NP were significantly higher in model group than control group (means 0.712 vs. 0.248, respectively, mg/gpro, p = 0.0026), and the levels of Heme Oxygenase 1 (HO-1) were also elevated in model group (means 14.33 vs. 5.16 IOD, respectively, p = 0.0002). However, the levels of ferritin light chain (FTL) were significantly decreased in model group compared to control group (means 26.17 vs. 9.00 FTL⁺ cell number, respectively, p = 0.0011).

CONCLUSIONS

Novel chondrocyte subsets in nucleus pulposus were discovered through scRNA-Seq, which provided novel insight to understand the pathological change during the development of IVDD. Ferroptosis participated in disc degeneration pathogenesis and it might serve as a new target for intervening IVDD.

Publication trends and hotspots in enhanced recovery after surgery: 20-year bibliometric analysis

We evaluated enhanced recovery after surgery (ERAS) research and used bibliometric analysis to quantitatively and qualitatively predict research hotspots through extracting relevant publications from the core collection of the Web of Science database.

Multiple-Scale Analysis of Water Quality Variations and Their Correlation with Land use in Highly Urbanized Taihu Basin, China

Understanding the relationship between land use and water quality at different scales is essential in the restoration and protection of water quality. On March 2014, we collected 97 samples in highly urbanized Taihu Basin and analyzed their water quality characteristics. Spatial differences in water quality were evident in sub-basins. The Hu Xi zone with the largest forest area had the best water quality among all the sub-basins. The correlation analysis indicated that the proportions of forest and construction land were significantly associated with multiple water quality variables from buffer to sub-basin scale. Farmland was significantly related to NO₃-N at the sub-basin scale. The impact of landscape metrics at the sub-basin was insignificant. Forest and construction land in the 1-2 km buffer zone appeared to have a greater influence on the water quality than the buffers with smaller distance. These results are beneficial toward the understanding of water quality status in highly urbanized watersheds and provide a reference for water quality conservation and land use management in the future.

Dynamic action of DNA repair proteins as revealed by single molecule techniques: Seeing is believing

DNA repair is a highly dynamic process in which the actual damage recognition process occurs through an amazing dance between the DNA duplex containing the lesion and the DNA repair proteins. Single molecule investigations have revealed that DNA repair proteins solve the speed-stability paradox, of rapid search versus stable complex formation, by conformational changes induced in both the damaged DNA and the repair proteins. Using Rad4, XPA, PARP1, APE1, OGG1 and UV-DDB as examples, we have discovered how these repair proteins limit their travel on DNA, once a lesion is encountered through a process of anomalous diffusion. We have also observed how PARP1 and APE1, as well as UV-DDB and OGG1 or APE1, co-localize dynamically at sites near DNA damage. This review highlights how our group has greatly benefited from our productive collaborations with Sam Wilson's research group.

A higher level of total bile acid in early mid-pregnancy is associated with an increased risk of gestational diabetes mellitus: a prospective cohort study in Wuhan, China

PURPOSE

To assess the longitudinal associations between maternal total bile acid (TBA) levels during early mid-pregnancy and the subsequent risk of gestational diabetes mellitus (GDM).

METHODS

In a prospective cohort study, pregnant women who were enrolled prior to gestational week 16 were followed until delivery. TBA levels were tested during weeks 14-18 of gestation. Using logistic regression, we analyzed the associations between quartiles of TBA and GDM based on a 75-g oral glucose tolerance test (OGTT) at 24-28 gestational weeks.

RESULTS

The GDM rate was 7.9% (114/1441). The mean TBA level was higher in women with GDM than in those without GDM (2.1 ± 2.0 vs 1.5 ± 1.0 µmol/L, P = 0.000). The highest TBA level quartile (2.1-10.7 µmol/L) had a 1.78-fold (95% CI 1.01, 3.14) increased risk of GDM compared with that of the lowest quartile (0.0-0.8 µmol/L) after adjusting for pre-pregnancy body mass index (BMI), gestational, age at TBA test and other confounders. High TBA levels were involved in the fasting glucose level rather than that at 1 h and 2 h after OGTT in all participants.

CONCLUSIONS

Pregnant women with higher serum TBA levels during early mid-pregnancy have a higher risk of developing GDM. TBA may be a new risk factor for GDM.

Human Condensin I and II Drive Extensive ATP-Dependent Compaction of Nucleosome-Bound DNA

Structural maintenance of chromosomes (SMC) complexes are essential for genome organization from bacteria to humans, but their mechanisms of action remain poorly understood. Here, we characterize human SMC complexes condensin I and II and unveil the architecture of the human condensin II complex, revealing two putative DNA-entrapment sites. Using single-molecule imaging, we demonstrate that both condensin I and II exhibit ATP-dependent motor activity and promote extensive and reversible compaction of double-stranded DNA. Nucleosomes are incorporated into DNA loops during compaction without being displaced from the DNA, indicating that condensin complexes can readily act upon nucleosome-bound DNA molecules. These observations shed light on critical processes involved in genome organization in human cells.

DNA Curtains Shed Light on Complex Molecular Systems During Homologous Recombination

Homologous recombination (HR) is important for the repair of double-stranded DNA breaks (DSBs) and stalled replication forks in all organisms. Defects in HR are closely associated with a loss of genome integrity and oncogenic transformation in human cells. HR involves coordinated actions of a complex set of proteins, many of which remain poorly understood. The key aspect of the research described here is a technology called "DNA curtains", a technique which allows for the assembly of aligned DNA molecules on the surface of a microfluidic sample chamber. They can then be visualized by total internal reflection fluorescence microscopy (TIRFM). DNA curtains was pioneered by our laboratory and allows for direct access to spatiotemporal information at millisecond time scales and nanometer scale resolution, which cannot be easily revealed through other methodologies. A major advantage of DNA curtains is that it simplifies the collection of statistically relevant data from single molecule experiments. This research continues to yield new insights into how cells regulate and preserve genome integrity.

Subnanosecond phase transition dynamics in laser-shocked iron

Iron is one of the most studied chemical elements due to its sociotechnological and planetary importance; hence, understanding its structural transition dynamics is of vital interest. By combining a short pulse optical laser and an ultrashort free electron laser pulse, we have observed the subnanosecond structural dynamics of iron from high-quality x-ray diffraction data measured at 50-ps intervals up to 2500 ps. We unequivocally identify a three-wave structure during the initial compression and a two-wave structure during the decaying shock, involving all of the known structural types of iron (α-, γ-, and ε-phase). In the final stage, negative lattice pressures are generated by the propagation of rarefaction waves, leading to the formation of expanded phases and the recovery of γ-phase. Our observations demonstrate the unique capability of measuring the atomistic evolution during the entire lattice compression and release processes at unprecedented time and strain rate.

A New Framework for Performing Cardiac Strain Analysis from Cine MRI Imaging in Mice

Cardiac magnetic resonance (MR) imaging is one of the most rigorous form of imaging to assess cardiac function in vivo. Strain analysis allows comprehensive assessment of diastolic myocardial function, which is not indicated by measuring systolic functional parameters using with a normal cine imaging module. Due to the small heart size in mice, it is not possible to perform proper tagged imaging to assess strain. Here, we developed a novel deep learning approach for automated quantification of strain from cardiac cine MR images. Our framework starts by an accurate localization of the LV blood pool center-point using a fully convolutional neural network (FCN) architecture. Then, a region of interest (ROI) that contains the LV is extracted from all heart sections. The extracted ROIs are used for the segmentation of the LV cavity and myocardium via a novel FCN architecture. For strain analysis, we developed a Laplace-based approach to track the LV wall points by solving the Laplace equation between the LV contours of each two successive image frames over the cardiac cycle. Following tracking, the strain estimation is performed using the Lagrangian-based approach. This new automated system for strain analysis was validated by comparing the outcome of these analysis with the tagged MR images from the same mice. There were no significant differences between the strain data obtained from our algorithm using cine compared to tagged MR imaging. Furthermore, we demonstrated that our new algorithm can determine the strain differences between normal and diseased hearts.

Diazoxide induces endoplasmic reticulum stress-related neuroprotection mediated by p38 MAPK against Aβ25-35 insults

OBJECTIVE

The endoplasmic reticulum (ER) -resident caspase-12 was identified as a mediator of Aβ neurotoxicity. Recent evidence indicates that mitochondrial ATP-sensitive potassium (KATP) channel openers mediate their neuroprotective role by adjusting ER stress pathways, but the molecular details remain largely unknown and have been investigated.

MATERIALS AND METHODS

In this study, the protein expression levels of calreticulin (CRT) and caspase-12 activation and phosphorylated p38 MAPK were observed by immunoblotting in cultured PC12 cells from different groups: treatment with Aβ25-35 (group Aβ25-35), treatment with diazoxide (group diazoxide), pretreatment with diazoxide and then exposure to Aβ25-35 (group diazoxide + Aβ25-35), pretreatment with p38 MAPK inhibitor SB 203580 and then exposure to diazoxide and Aβ25-35 (group SB 203580 + diazoxide + Aβ25-35), and the control (group control).

RESULTS

In response to the treatment with Aβ25-35 (10 µM) for 24 h, the protein expression levels of CRT and caspase-12 activation were increased and phosphorylated p38 MAPK was decreased significantly. Diazoxide reduced CRT overexpression and caspase-12 activation and increased the up-regulation of phosphorylated p38 MAPK. When SB 203580 was presented before exposure to diazoxide and Aβ25-35, CRT expression was markedly suppressed, and the inhibition effect of diazoxide on caspase-12 activation was almost eliminated.

CONCLUSIONS

We showed that diazoxide induced ERS-related neuroprotection mediated by p38 MAPK against Aβ25-35 insults. From the clinical point of view, these results are of considerable importance for the understanding of AD pathogenesis. However, further studies are required to explore more detailed mechanisms of the observed effects.

Linc-ROR promotes endometrial cell proliferation by activating the PI3K-Akt pathway

OBJECTIVE

To observe the expressions of Linc-ROR and proteins in the PI3K-Akt pathway in an ectopic lesion of adenomyosis.

PATIENTS AND METHODS

The expression of Linc-ROR in the ectopic endometrium, eutopic endometrium, and normal endometrium of adenomyosis was detected by qRT-PCR. Western blot was used to detect the protein expressions of PI3K-Akt in endometriosis and lesion endometriosis. Cell counting kit-8 (CCK-8) assay was utilized to detect cell proliferative activity. After interfering or overexpressing Linc-ROR, protein expressions of the PI3K-Akt pathway were detected by Western blot.

RESULTS

Linc-ROR expression in the ectopic endometrium of adenomyosis was higher than that in the eutopic endometrium and normal endometrium, and the expression level of PTEN in adenomyosis tissues was decreased, whilst expression levels of Akt, p-Akt, p-PTEN were increased. Clinical data of enrolled patients indicated that there was a relationship between Linc-ROR expression and the type and severity of dysmenorrhea of adenomyosis. However, no relationship was observed between Linc-ROR expression and age, cesarean section, uterine surgery, and menstrual cycle. Cell counting kit-8 (CCK-8) assay showed that the proliferative activity of cells was significantly decreased after knockdown of Linc-ROR in the adenomyosis cells. Western blot revealed that the expression level of PTEN increased but the expression levels of p-Akt, p-PTEN and p-PDK1 decreased. Overexpression of Linc-ROR obtained the opposite results.

CONCLUSIONS

Linc-ROR is highly expressed in the ectopic endometrium of adenomyosis, and it can promote the proliferative activity of endometrial cells by activating the PI3K-Akt pathway.

Abstract P5-12-07: Expression of adipocyte fatty acid binding protein promotes obesity-associated mammary tumor growth

Background: The underlying mechanisms that drive obesity-related breast cancer remain unclear. Adipocyte/macrophage fatty acid binding protein (A-FABP) is linked to obesity and breast cancer, while transforming growth factor (TGF)β appears to play a pleiotropic role in breast cancer, suppressing its development but promoting its progression. Whether the proteins work together to drive breast cancer progression is not known. We evaluated the expression of these two markers in matched serum from healthy women and women with breast cancer.

Hypothesis: A-FABP and TGFβ drive breast cancer development and progression.

Methods: Serum was collected under an institutional review board approved protocol. A-FABP was measured in serum collected from 275 women (92 with breast cancer and 183 without) and TGFβ from 245 matched women (92 with breast cancer and 153 without). A-FABP levels were measured using a human A-FABP4 ELISA kit while TGFβ was measured using human TGFβ ELISA kit. The Kruskal-Wallis test was used to determine if a difference in marker expression existed between women with and without breast cancer, as well as in women with early vs. more advanced breast cancer. Linear mixed effect models were used to examine the relationship between A-FABP and BMI, as well as between TGFβ and BMI, controlling for age, menopause status and a diagnosis of breast cancer.

Results:A-FABP expression was higher in obese than lean postmenopausal women, both those with breast cancer (mean : 44.9 vs. 25.1 ng/mL, p=0.002) and without breast cancer (39.4 vs. 26.9 ng/mL, p=0.003). A-FABP expression was also higher in premenopausal obese vs. lean women with cancer (28.9 vs. 12.7 ng/mL, p=0.027), but not in premenopausal healthy women. A-FABP expression was higher in postmenopausal obese vs. lean women with early stage (0-2A) breast cancer (45.6 vs. 21.9 ng/mL, p=0.013) and was inversely associated with HER-2 expression, though being of borderline significance (p=0.060). This was most notable among triple negative vs. ER/PR negative HER2 positive breast cancers. Considering both early and advanced breast cancer, TGFβ expression trended higher in post- than in pre-menopausal obese women with breast cancer (138.9 vs. 68.7 pg/mL, p=0.061), however among premenopausal women with advanced (Stages 2B-3C) disease, TGFβ expression was 5 fold higher in lean than obese individuals (251.7 vs. 48.2 pg/mL, p=0.029) but trended higher in obese vs lean postmenopausal women. TGFβ and A-FABP were found to be significantly associated (ρ=0.14, p=0.024).

Impact: Both A-FABP and TGFβ expression are associated with postmenopausal breast cancer among obese women, and their expression in matched samples is significantly associated.. TGFβ is associated with premenopausal advanced breast cancer in premenopausal women. TGFβ is known to induce epithelial mesenchymal transition and may play a role in pregnancy associated breast cancer. Further studies are needed to determine if A-FABP and TGFβ work together in postmenopausal breast cancer.

Citation Format: Sauter E, Hao J, Yan X, Kong M, Li B. Expression of adipocyte fatty acid binding protein promotes obesity-associated mammary tumor growth [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-07.

Transcatheter aortic valve replacement in atypical valve anatomy using the Lotus valve : A Chinese single-center experience

BACKGROUND

In the West, the safety and efficacy of the Lotus valve have been demonstrated; however, data in the Chinese population are still lacking. Few studies have compared the clinical outcomes of transcatheter aortic valve replacement (TAVR) with the Lotus valve in patients with bicuspid or tricuspid aortic valve stenosis. Our aim was to assess TAVR outcomes with the Lotus aortic valve in a Chinese patient cohort.

METHODS

In total, 23 symptomatic, high-surgical risk patients with severe aortic valve stenosis were enrolled. Among them, nine patients (39%) had bicuspid aortic valves, and three patients had a large annulus dimension. The Lotus valve was successfully implanted in all patients. To facilitate accurate positioning, partial re-sheathing was attempted in ten patients (43.5%), while one patient had a full retrieval. One-year clinical follow-up was completed in all patients.

RESULTS

There were no deaths, strokes, or major adverse cardiac and cerebrovascular events in 22 of the 23 patients at 30 days; the all-cause mortality rate at 1 year was 4.4% (1 of 23 patients). The mean aortic valve gradient decreased from 51.5 ± 8.8 mm Hg at baseline to 13.4 ± 4.9 mm Hg (p < 0.001) and the valve area increased from 0.6 ± 0.2 cm² to 1.5 ± 0.4 cm² (p < 0.001) at 30 days. Paravalvular leakage was absent or mild (22%), and no patient had severe paravalvular leakage. Six patients (26.1%) required a postprocedural pacemaker. There was no difference regarding the procedural and the 1‑year outcomes between patients with bicuspid and tricuspid aortic valve stenosis.

CONCLUSION

Our single-center experience demonstrated that the Lotus valve is feasible and effective for Chinese patients with aortic valve stenosis, including atypical cases with bicuspid aortic valves or large aortic annulus size.

The combination of apolipoprotein E4, age and Alzheimer's Disease Assessment Scale - Cognitive Subscale improves the prediction of amyloid positron emission tomography status in clinically diagnosed mild cognitive impairment

BACKGROUND AND PURPOSE

Randomized clinical trials involving anti-amyloid interventions focus on the early stages of Alzheimer's disease (AD) with proven amyloid pathology, using amyloid positron emission tomography (amyloid-PET) imaging or cerebrospinal fluid analysis. However, these investigations are either expensive or invasive and are not readily available in resource-limited centres. Hence, the identification of cost-effective clinical alternatives to amyloid-PET is highly desirable. This study aimed to investigate the accuracy of combined clinical markers in predicting amyloid-PET status in mild cognitive impairment (MCI) individuals.

METHODS

In all, 406 MCI participants from the Alzheimer's Disease Neuroimaging Initiative database were dichotomized into amyloid-PET(+) and amyloid-PET(-) using a cut-off of >1.11. The accuracies of single clinical markers [apolipoprotein E4 (ApoE4) genotype, demographics, cognitive measures and cerebrospinal fluid analysis] in predicting amyloid-PET status were evaluated using receiver operating characteristic curve analysis. A logistic regression model was then used to determine the optimal model with combined clinical markers to predict amyloid-PET status.

RESULTS

Cerebrospinal fluid amyloid-β (Aβ) showed the best predictive accuracy of amyloid-PET status [area under the curve (AUC) = 0.927]. Whilst ApoE4 genotype (AUC = 0.737) and Alzheimer's Disease Assessment Scale - Cognitive Subscale (ADAS-Cog) 13 (AUC = 0.724) independently discriminated amyloid-PET(+) and amyloid-PET(-) MCI individuals, the combination of clinical markers (ApoE4 carrier, age >60 years and ADAS-Cog 13 > 13.5) improved the predictive accuracy of amyloid-PET status (AUC = 0.827, P < 0.001).

CONCLUSIONS

Cerebrospinal fluid Aβ, which is an invasive procedure, is most accurate in predicting amyloid-PET status in MCI individuals. The combination of ApoE4, age and ADAS-Cog 13 also accurately predicts amyloid-PET status. As this combination of clinical markers is cheap, non-invasive and readily available, it offers an attractive surrogate assessment for amyloid status amongst MCI individuals in resource-limited settings.

S-nitrosylation of Src by NR2B-nNOS signal causes Src activation and NR2B tyrosine phosphorylation in levodopa-induced dyskinetic rat model

Abnormality in Src PSD-95 NR2B signaling complex assemble occurs in levodopa-induced dyskinesia (LID). N-methyl-D-aspartate receptor (NMDAR) subunit NR2B tyrosine phosphorylation mediated by Src family protein tyrosine kinases is closely associated with dyskinesia. Src autophosphorylation (p-Src) is an important part of Src-catalyzed phosphorylation of NR2B. In addition, the neuronal nitric oxide synthase (nNOS)-derived NO (nNOS/NO) signal which was also involved in dyskinesia recently was proved to participate in the regulation of Src function. Yet, the detailed signal mechanism about the interactions of NR2B, nNOS, and Src is still unknown. In the present study, we investigated the influences of nNOS on Src activation and NR2B tyrosine phosphorylation in dyskinetic rat model by immunoblotting and immunoprecipitation. The results demonstrated that chronic levodopa treatment resulted in downregulation of p-nNOS-S847, one marker of nNOS overactivation. Coinstantaneously, the S-nitrosylation (SNO-Src) and autophosphorylation (p-Src) of Src and NR2B tyrosine phosphorylation were upregulated in dyskinetic rat model. Conversely, administration of 7-NI, one nNOS inhibitor, reversed all these effects of levodopa treatment. Besides, NR2B-containing NMDAR (NR2B/NMDAR) antagonist CP-101,606 could upregulate p-nNOS-S847 and thus attenuate nNOS activation and simultaneously reduce the SNO-Src, p-Src, and NR2B tyrosine phosphorylation. Taken together, the S-nitrosylation of Src is caused by nNOS/NO signal, which is overactivated via Ca²⁺ influx dependent on NR2B/NMDAR, and subsequently facilitates Src auto-tyrosine phosphorylation and further phosphorylates NR2B. The "NR2B/NMDAR-nNOS/NO-SNO-Src-p-Src-NR2B/NMDAR" signaling cycle may be the molecular basis of NR2B tyrosine phosphorylation upward positive feedback, which demonstrates the possibility as one latent target for dyskinesia therapy.

PARP1 changes from three-dimensional DNA damage searching to one-dimensional diffusion after auto-PARylation or in the presence of APE1

PARP1-dependent poly-ADP-ribosylation (PARylation) participates in the repair of many forms of DNA damage. Here, we used atomic force microscopy (AFM) and single molecule fluorescence microscopy to examine the interactions of PARP1 with common DNA repair intermediates. AFM volume analysis indicates that PARP1 binds to DNA at nicks, abasic (AP) sites, and ends as a monomer. Single molecule DNA tightrope assays were used to follow the real-time dynamic behavior of PARP1 in the absence and presence of AP endonuclease (APE1) on AP DNA damage arrays. These experiments revealed that PARP1 conducted damage search mostly through 3D diffusion. Co-localization of APE1 with PARP1 on DNA was found capable of inducing 1D diffusion of otherwise nonmotile PARP1, while excess APE1 also facilitated the dissociation of DNA-bound PARP1. Moreover, auto-PARylation of PARP1 allowed the protein to switch its damage search strategy by causing a 3-fold increase in linear diffusion. Finally, we demonstrated that PARP inhibitor olaparib did not significantly alter the rate of PARP1 dissociation from DNA, but instead resulted in more motility of DNA-bound PARP1 molecules.

Fusarium oxysporum f. sp. mori, a New Forma Specialis Causing Fusarium Wilt of Blackberry

Fusarium oxysporum has recently been identified as the cause of a wilt disease affecting blackberry in California and Mexico. Thirty-six isolates of F. oxysporum obtained from symptomatic blackberry plants in California and Mexico were comprised of nine distinct somatic compatibility groups (SCGs). Phylogenetic analysis of a concatenated data set, consisting of sequences of the translation elongation factor 1-α and β-tubulin genes and the intergenic spacer of the ribosomal DNA, identified nine three-locus sequence types, each of which corresponded to an SCG. Six SCGs were present only in California, two only in Mexico, and one in both California and Mexico. An isolate associated with the most common SCG in California was tested for pathogenicity on blueberry, raspberry, strawberry, and lettuce. All blueberry, raspberry, and lettuce plants that were inoculated remained healthy, but two of the five strawberry cultivars tested developed symptoms. The three strawberry cultivars that were resistant to the blackberry pathogen were also resistant to F. oxysporum f. sp. fragariae, the cause of Fusarium wilt of strawberry. We propose to designate strains of F. oxysporum that are pathogenic to blackberry as Fusarium oxysporum f. sp. mori forma specialis nov.

Studying protein-DNA interactions using atomic force microscopy

Atomic force microscopy (AFM) has made significant contributions to the study of protein-DNA interactions by making it possible to topographically image biological samples. A single protein-DNA binding reaction imaged by AFM can reveal protein binding specificity and affinity, protein-induced DNA bending, and protein binding stoichiometry. Changes in DNA structure, complex conformation, and cooperativity, can also be analyzed. In this review we highlight some important examples in the literature and discuss the advantages and limitations of these measurements. We also discuss important advances in technology that will facilitate the progress of AFM in the future.

Single-Molecule Methods for Nucleotide Excision Repair: Building a System to Watch Repair in Real Time

Single-molecule approaches to solving biophysical problems are powerful tools that allow static and dynamic real-time observations of specific molecular interactions of interest in the absence of ensemble-averaging effects. Here, we provide detailed protocols for building an experimental system that employs atomic force microscopy and a single-molecule DNA tightrope assay based on oblique angle illumination fluorescence microscopy. Together with approaches for engineering site-specific lesions into DNA substrates, these complementary biophysical techniques are well suited for investigating protein-DNA interactions that involve target-specific DNA-binding proteins, such as those engaged in a variety of DNA repair pathways. In this chapter, we demonstrate the utility of the platform by applying these techniques in the studies of proteins participating in nucleotide excision repair.

Optical Control of DNA Helicase Function through Genetic Code Expansion

Nucleotide excision repair (NER) is a general DNA repair mechanism that is capable of removing a wide variety of DNA lesions induced by physical or chemical insults. UvrD, a member of the helicase SF1 superfamily, plays an essential role in bacterial NER by unwinding the duplex DNA in the 3' to 5' direction to displace the lesion-containing strand. In order to achieve conditional control over NER, we generated a light-activated DNA helicase. This was achieved through a site-specific incorporation of a genetically encoded hydroxycoumarin lysine at a crucial position in the ATP-binding pocket of UvrD. The resulting caged enzyme was completely inactive in several functional assays. Moreover, enzymatic activity of the optically triggered UvrD was comparable to that of the wild-type protein, thus demonstrating excellent OFF to ON switching of the helicase. The developed approach provides optical control of NER, thereby laying a foundation for the regulation of ATP-dependent helicase functions in higher organisms. In addition, this methodology is applicable to the light-activation of a wide range of ATPases.

Tumor-associated mutant p53 promotes cancer cell survival upon glutamine deprivation through p21 induction

Cancer cells depend on glutamine to sustain their increased proliferation and manage oxidative stress, yet glutamine is often depleted at tumor sites due to excessive cellular consumption and poor vascularization. We have previously reported that p53 protein, while a well-known tumor suppressor, can contribute to cancer cell survival and adaptation to low glutamine conditions. However, the TP53 gene is frequently mutated in tumors, and the role of mutant p53 (mutp53) in response to metabolic stress remains unclear. Here, we demonstrate that tumor-associated mutp53 promotes cancer cell survival upon glutamine deprivation both in vitro and in vivo. Interestingly, cancer cells expressing mutp53 proteins are more resistant to glutamine deprivation than cells with wild type p53 (wtp53). Depletion of endogenous mutp53 protein in human lymphoma cells leads to cell sensitivity to glutamine withdrawal, while expression of mutp53 in p53 null cells results in resistance to glutamine deprivation. Furthermore, we found that mutp53 proteins hyper-transactivate p53 target gene CDKN1A upon glutamine deprivation, thus triggering cell cycle arrest and promoting cell survival. Together, our results reveal an unidentified mechanism by which mutp53 confers oncogenic functions by promoting cancer cell adaptation to metabolic stresses.

[Clinicopathologic analysis of anastomosing hemangioma of the kidney and adrenal gland]

Objective: To investigate the clinical and histopathologic characteristics, diagnosis, differential diagnosis and prognostic features of anastomosing hemangioma. Methods: Five cases of anastomosing hemangioma of the kidney and adrenal gland were collected, the clinical and radiologic features, histomorphology, immunophenotype and prognosis were analyzed with review of literature. Results: Three patients were male and two were female with ages ranging from 47 to 77 years; three were located in adrenal gland and 2 originated from the kidney. Clinically, 4 tumors were incidentally identified, 1 presented as edema of lower extremity. By radiography, all presented as a well-demarcated, oval, solid and low-density mass. Grossly, the tumors ranged in maximum diameter from 1.6 to 2.5 cm (mean 2.1 cm). Microscopically, the tumors consisted of anastomosing sinusoidal capillary-sized vessels lined by a single layer of flattened, cubical to hobnail endothelial cells, setting in an pauci-cellular stroma of edematous and hyaline changes. Other commonly seen features included vaguely lobular growth pattern (3/5), hemorrhage and thrombosis (5/5), intravascular growth pattern (5/5), eosinophilic intracytoplasmic hyaline globules (1/5) and extramedullary hematopoiesis (3/5). The tumor cells were typically bland-appearing and mitoses were scarce, with 1 case demonstrating cellular foci of tumor with slight pleomorphism and increased mitoses (2/50 HPF). Immunohistochemical studies showed the tumor cells expressed endothelial cells markers. Follow-up information was available for all 5 patients and showed no evidence of tumor recurrence or metastasis within 6 to 52 months (mean 30 months). Conclusions: Anastomosing hemangioma is a rare, benign subtype of capillary hemangioma that predominantly affects the urologic organs and adrenal glands; it is needed to distinguish it histologically from a series of benign or malignant tumors that feature a richly vascular stroma. Careful attentions to its characteristic morphology with the judicious use of immunohistochemistry can help distinguish this tumor from its many mimickers.

Participation of protein kinases and phosphatases in the progesterone-induced acrosome reaction and calcium influx in human spermatozoa

In human spermatozoa, protein kinases have a role in the acrosome reaction (AR) induced by a variety of stimuli. However, there is disagreement or a lack of information regarding the role of protein kinases and phosphatases in the progesterone (P)-induced increase in intracellular calcium concentration ([Ca²⁺ ]_i ). In addition, there are no studies regarding the role of Ser/Thr and Tyr phosphatases and there are contradictory results regarding the role of Tyr kinases in the P-induced acrosome reaction. Here, we performed a simultaneous evaluation of the involvement of protein kinases and phosphatases in the P-induced acrosome reaction and in the P-induced calcium influx. Motile spermatozoa were capacitated for 18 h and different aliquots were allocated to treated or control groups and then evaluated for their ability to undergo the acrosome reaction and to increase [Ca²⁺ ]_i in response to P. The acrosome reaction was evaluated using Pisum sativum agglutinin (PSA)-FITC, and [Ca²⁺ ]_i was evaluated using fura 2AM. At all of the concentrations tested, PKA inhibitors significantly reduced the percentage of the P-induced acrosome reaction (p < 0.001). However, only the highest concentrations of PKA inhibitors reduced the P-induced calcium influx; lower concentrations of PKA inhibitors did not affect it. Similar results were apparent for PKC inhibitors and for tyrosine kinase inhibitors. None of the Ser/Thr phosphatase inhibitors affected the P-induced acrosome reaction or the P-induced calcium influx, except for the PP2B inhibitors that significantly reduced the P-induced acrosome reaction without affecting calcium influx. Finally, the protein tyrosine phosphatase inhibitors significantly blocked the P-induced acrosome reaction and reduced the amplitude of the P-induced calcium transient (p < 0.001) as well as the amplitude of the plateau phase (p < 0.01). The data suggest that protein kinases and possibly PP2B have a role on the acrosome reaction at some point downstream of calcium entry and that Tyr phosphatases have a role on the acrosome reaction upstream of calcium entry.

Molecular Profile of Mitochondrial Dysfunction in Kidney Transplant Biopsies Is Associated With Poor Allograft Outcome

BACKGROUND

In kidney transplantation (KT), progression of chronic histological damage with subclinical inflammation is associated with poor long-term allograft survival. The role of nonimmunological pathways in chronic allograft injury has not been fully assessed.

METHODS

We analyzed a public microarray dataset that used 1-year protocol kidney transplant biopsy specimens to investigate whether nonimmunological genes and pathways might influence long-term allograft outcome. The selected microarray dataset included 3 patient/sample groups based on their histological findings: normal histology (n = 25), interstitial fibrosis alone (IF alone, n = 24), and interstitial fibrosis with inflammation (IF+i, n = 16). The IF+i group had lower death-censored graft survival and renal function in patients with a mean follow-up of 4 years. We performed statistical analysis comparing gene expression patterns in the 3 group samples.

RESULTS

Gene cluster enrichment and group-specific expression patterns demonstrated a divergent pattern between mitochondrial and immune response genes, with downregulation of mitochondrial genes in the IF+i group. Gene ontological analysis of the downregulated mitochondrial genes identified generation of precursor metabolite and energy, and response to oxidative stress as the most significant biological processes. The transcription regulation pathway analysis of downregulated gene cluster demonstrated transcription factors involved in mitochondrial biogenesis.

CONCLUSIONS

The molecular signature of mitochondrial dysfunction reflects mitochondrial energetic insufficiency, and inadequate antioxidant response involved in mitochondria biogenesis pathways is associated with IF+i and worse long-term allograft survival. Thus, mitochondria function impairment appears to be an important nonimmune factor involved in chronic allograft injury.

Fibronectin stimulates human sperm capacitation through the cyclic AMP/protein kinase A pathway

STUDY QUESTION

Does fibronectin (Fn) stimulate the sperm capacitation process in humans?

SUMMARY ANSWER

Fibronectin stimulates human sperm capacitation.

WHAT IS KNOWN ALREADY

Capacitation is a process that occurs in the oviduct. It has been suggested that some molecules present in the oviductal fluid and cells as well as proteins present in the cumulus oophorus could be involved in the modulation of sperm function and their acquisition of fertilizing capacity. Fibronectin is a glycoprotein that is present in the fluid and the oviduct epithelium, and its receptor (alpha 5 beta 1 integrin) is present in human sperm. When alpha 5 beta 1 (α5β1) integrin binds to fibronectin, intracellular signals similar to the process of sperm capacitation are activated.

STUDY DESIGN, SIZE, DURATION

Human sperm were selected via a percoll gradient and were then incubated in non-capacitated medium (NCM) or reconstituted capacitated medium (RCM), in the presence or absence of fibronectin for different time periods. A total of 39 donors were used during the study, which lasted 3 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Freshly ejaculated sperm from healthy volunteers were obtained by masturbation. All semen samples were normal according to the World Health Organization parameters. Six approaches were used to determine the effects of fibronectin on sperm capacitation: chlortetracycline (CTC) assay, heterologous co-culture of human sperm with bovine oviductal epithelial cells (BOEC), measurement of cyclic (c) AMP levels, activity of protein kinase A (PKA), phosphorylation of proteins in tyrosine (Tyr) residues, and induction of acrosome reaction with progesterone.

MAIN RESULTS AND THE ROLE OF CHANCE

When sperm were incubated in RCM in the presence of Fn, we observed differences with respect to sperm incubated in RCM without Fn (control): (i) a 10% increase in the percentage of sperm with the B pattern (capacitated sperm) of CTC fluorescence from the beginning of capacitation (P < 0.001); (ii) an effect on both the concentration of cAMP (P < 0.05) and PKA activity (P < 0.05) during early capacitation; (iii) an increase in the degree of phosphorylation of proteins on tyrosine residues after 60 min of capacitation (P < 0.01); (iv) an increase in the percentage of acrosome-reacted sperm in response to progesterone (P < 0.05); and (v) a decrease in the percentage of sperm attached to BOEC (P < 0.05). Moreover, we noted that the effect of Fn was specific and mediated by alpha 5 beta 1 integrin (P < 0.001). Fn by itself had no effect on sperm capacitation.

LIMITATIONS, REASONS FOR CAUTION

This study was carried out with sperm from young adult men. Men with abnormal semen samples were excluded. The results cannot be directly extrapolated to other mammalian species.

WIDER IMPLICATIONS OF THE FINDINGS

Currently, male subfertility has become a huge public health problem, which makes it imperative to develop new treatments. This is a novel discovery that extends our current knowledge concerning normal and pathological sperm physiology as well as events that regulate the process of fertilization.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from FONDECYT (1130341, E.S.D. and 1120056, P.M.) and FONCYT (PIP 2011-0496, S.P.-M). The authors have no conflicts of interest.

Signaling pathways involved in neuron-astrocyte adhesion and migration

Astrocytes in the normal brain possess a stellate shape reflecting their non-migratory properties. Alternatively, in neurodegenerative diseases or after injury, astrocytes become "reactive" in a process known as astrocytosis or reactive gliosis, retract their processes, become polarized and acquire front-to-rear asymmetry typical of migratory cells. On the other hand, neuronal migration is a common process during embryonic development, but only few types of neurons can migrate and differentiate during adult life in the central nervous system. Those that do migrate follow tracks made by glial cells and mainly give rise to interneurons. In vitro, molecular mechanisms involved in adhesion of cells to and migration on extracellular matrix proteins have been widely studied; however, signal transduction pathways explaining how particularly neurons and astrocytes, mutually modulate adhesion and migration are less well known. In this review, we describe and discuss how ligand/receptor interactions in astrocytes and neurons trigger signaling events leading to actin and microtubule reorganization, changes in cell morphology, as well as cell adhesion and migration. The biological significance these cell-cell interactions and signaling events might have in the brain are discussed.