Helicobacter pylori infection downregulates the DNA glycosylase NEIL2, resulting in increased genome damage and inflammation in gastric epithelial cells

Infection with the Gram-negative, microaerophilic bacterium Helicobacter pylori induces an inflammatory response and oxidative DNA damage in gastric epithelial cells that can lead to gastric cancer (GC). However, the underlying pathogenic mechanism is largely unclear. Here, we report that the suppression of Nei-like DNA glycosylase 2 (NEIL2), a mammalian DNA glycosylase that specifically removes oxidized bases, is one mechanism through which H. pylori infection may fuel the accumulation of DNA damage leading to GC. Using cultured cell lines, gastric biopsy specimens, primary cells, and human enteroid-derived monolayers from healthy human stomach, we show that H. pylori infection greatly reduces NEIL2 expression. The H. pylori infection-induced downregulation of NEIL2 was specific, as Campylobacter jejuni had no such effect. Using gastric organoids isolated from the murine stomach in coculture experiments with live bacteria mimicking the infected stomach lining, we found that H. pylori infection is associated with the production of various inflammatory cytokines. This response was more pronounced in Neil2 knockout (KO) mouse cells than in WT cells, suggesting that NEIL2 suppresses inflammation under physiological conditions. Notably, the H. pylori-infected Neil2-KO murine stomach exhibited more DNA damage than the WT. Furthermore, H. pylori-infected Neil2-KO mice had greater inflammation and more epithelial cell damage. Computational analysis of gene expression profiles of DNA glycosylases in gastric specimens linked the reduced Neil2 level to GC progression. Our results suggest that NEIL2 downregulation is a plausible mechanism by which H. pylori infection impairs DNA damage repair, amplifies the inflammatory response, and initiates GC.

The DNA Glycosylase NEIL2 Suppresses Fusobacterium-Infection-Induced Inflammation and DNA Damage in Colonic Epithelial Cells

Colorectal cancer (CRC) is the third most prevalent cancer, while the majority (80-85%) of CRCs are sporadic and are microsatellite stable (MSS), and approximately 15-20% of them display microsatellite instability (MSI). Infection and chronic inflammation are known to induce DNA damage in host tissues and can lead to oncogenic transformation of cells, but the role of DNA repair proteins in microbe-associated CRCs remains unknown. Using CRC-associated microbes such as Fusobacterium nucleatum (Fn) in a coculture with murine and human enteroid-derived monolayers (EDMs), here, we show that, among all the key DNA repair proteins, NEIL2, an oxidized base-specific DNA glycosylase, is significantly downregulated after Fn infection. Fn infection of NEIL2-null mouse-derived EDMs showed a significantly higher level of DNA damage, including double-strand breaks and inflammatory cytokines. Several CRC-associated microbes, but not the commensal bacteria, induced the accumulation of DNA damage in EDMs derived from a murine CRC model, and Fn had the most pronounced effect. An analysis of publicly available transcriptomic datasets showed that the downregulation of NEIL2 is often encountered in MSS compared to MSI CRCs. We conclude that the CRC-associated microbe Fn induced the downregulation of NEIL2 and consequent accumulation of DNA damage and played critical roles in the progression of CRCs.

Effects of platelet-rich plasma against experimental ischemia/reperfusion injury in rat testis

BACKGROUND

Testicular torsion is a common problem and, to date, there is no agent to preserve testicular function following detorsion. Platelet-rich plasma (PRP), with its rich growth factor composition, has proven beneficial in regenerative therapy. It is believed that PRP has not been studied in testis for ischemia/reperfusion (I/R) injury.

OBJECTIVE

This study investigated the effect of PRP in an I/R rat model 1 month after detorsion.

STUDY DESIGN

Of 24 adult male Sprague-Dawley rats, 18 were randomly assigned into three groups, with six in each: control, I/R and I/R + PRP. The PRP was prepared from the remaining six. Each group underwent right orchiectomy. Ischemia was performed by rotating the left testis 720° and fixing with a nylon suture for 4 h. Reperfusion occurred 4 h later by removing the suture, and PRP was administered at a dose of 10 μl (2000 × 10⁹/l) into the left testis via the intraparenchymal route. Animals were sacrificed at the fourth week, and testes were taken for malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), myeloperoxidase (MPO), transforming growth factor β (TGF-β), and caspase-3 measurements.

RESULTS

Ischemia/reperfusion caused a significant increase in MDA, MPO and caspase-3 activity, and significant decrease in GSH levels and SOD activity. The PRP treatment helped correct the alterations in SOD, caspase-3, and MPO activities and MDA levels. However, the mean MDA level and MPO activity were not totally restored compared with the controls. Serum testosterone levels of the I/R group were significantly lower compared with the control and I/R + PRP groups. TGF-β and caspase-3 protein expressions were significantly higher in the I/R group compared with the control group and were low with PRP administration compared with I/R groups (summary Table).

DISCUSSION

The findings of the present study suggest that PRP, by inhibiting neutrophil infiltration and oxidative stress and increasing antioxidant defense, exerts protective effects on testicular tissues against I/R. This study had some limitations: a scoring system was not used in the assessment of spermatogenesis in the histopathological findings and specific testis cell types were not histologically assessed.

CONCLUSIONS

In light of the biochemical, histological and, especially, hormonal findings, intraparenchymal PRP injection may have a protective effect in testicular tissue against I/R injury.

The Pivotal Role of DNA Repair in Infection Mediated-Inflammation and Cancer

Pathogenic and commensal microbes induce various levels of inflammation and metabolic disease in the host. Inflammation caused by infection leads to increased production of reactive oxygen species (ROS) and subsequent oxidative DNA damage. These in turn cause further inflammation and exacerbation of DNA damage, and pose a risk for cancer development. Helicobacter pylori-mediated inflammation has been implicated in gastric cancer in many previously established studies, and Fusobacterium nucleatum presence has been observed with greater intensity in colorectal cancer patients. Despite ambiguity in the exact mechanism, infection-mediated inflammation may have a link to cancer development through an accumulation of potentially mutagenic DNA damage in surrounding cells. The multiple DNA repair pathways such as base excision, nucleotide excision, and mismatch repair that are employed by cells are vital in the abatement of accumulated mutations that can lead to carcinogenesis. For this reason, understanding the role of DNA repair as an important cellular mechanism in combatting the development of cancer will be essential to characterizing the effect of infection on DNA repair proteins and to identifying early cancer biomarkers that may be targeted for cancer therapies and treatments.

Biomimetic Hydrogels in the Study of Cancer Mechanobiology: Overview, Biomedical Applications, and Future Perspectives

Hydrogels are biocompatible polymers that are tunable to the system under study, allowing them to be widely used in medicine, bioprinting, tissue engineering, and biomechanics. Hydrogels are used to mimic the three-dimensional microenvironment of tissues, which is essential to understanding cell–cell interactions and intracellular signaling pathways (e.g., proliferation, apoptosis, growth, and survival). Emerging evidence suggests that the malignant properties of cancer cells depend on mechanical cues that arise from changes in their microenvironment. These mechanobiological cues include stiffness, shear stress, and pressure, and have an impact on cancer proliferation and invasion. The hydrogels can be tuned to simulate these mechanobiological tissue properties. Although interest in and research on the biomedical applications of hydrogels has increased in the past 25 years, there is still much to learn about the development of biomimetic hydrogels and their potential applications in biomedical and clinical settings. This review highlights the application of hydrogels in developing pre-clinical cancer models and their potential for translation to human disease with a focus on reviewing the utility of such models in studying glioblastoma progression.

The relationship between anogenital distance and lifelong premature ejaculation

BACKGROUND

Many diseases have been associated with anogenital distance, as an indicator of intrauterine androgen exposure.

OBJECTIVES

The aim of this study was to investigate the association between lifelong premature ejaculation and anogenital distance.

MATERIALS AND METHODS

The study included 140 participants: 70 with lifelong premature ejaculation (group 1) and 70 without any ejaculatory complaints (group 2). Premature Ejaculation Diagnostic Tool and stopwatch intravaginal ejaculatory latency time were recorded from all participants in order to evaluate ejaculatory function. Two variants of anogenital distance were measured: anogenital distance (from anus to the posterior base of the scrotum) from anus to the posterior base of the scrotum and anogenital distance (from anus to the cephalad insertion of the penis) to the cephalad insertion of the penis. We compared differences between groups and correlations between anogenital distance variants and patients' characteristics.

RESULTS

The groups were similar in terms of age, BMI, and total testosterone levels. The mean anogenital distance (from anus to the posterior base of the scrotum) scores were 59.45 ± 10.76 vs. 55.02 ± 10.13 (p = 0.01), and anogenital distance (from anus to the cephalad insertion of the penis) scores were 128.37 ± 22.2 vs. 126.78 ± 16.21 (p = 0.63) in groups 1 and 2, respectively. Significant correlation was observed between anogenital distance (from anus to the posterior base of the scrotum) and Premature Ejaculation Diagnostic Tool scores (r = 0.199, p = 0.019) and intravaginal ejaculatory latency time (r = -0.185, p = 0.028). There were no statistically significant differences between anogenital distance (from anus to the posterior base of the scrotum) scores and total testosterone levels and between anogenital distance (from anus to the cephalad insertion of the penis) and Premature Ejaculation Diagnostic Tool scores or intravaginal ejaculatory latency time.

CONCLUSIONS

These results suggest that longer anogenital distance is associated with higher possibility of lifelong premature ejaculation. However, further studies are needed to confirm our results.

Lysosomal PIP3 revealed by genetically encoded lipid biosensors

3-Phosphoinositides (3-PIs), phosphatidylinositol (3,4) bisphosphate [PI(3,4)P2] and phosphatidylinositol (3,4,5) trisphosphate (PIP3), are important lipid second messengers in the Phosphoinositide 3-Kinase (PI3K)/Akt signaling pathway, which is crucial to cell growth and frequently dysregulated in cancer. Emerging evidence suggests these lipid second messengers may be present in membranes beyond the plasma membrane, yet their spatial regulation within other membrane compartments is not well understood. To dissect the spatial regulation of specific 3-PI species, we developed genetically encodable biosensors with selectivity for PIP3 or PI(3,4)P2. Using these biosensors, we showed that PIP3 significantly accumulated at the lysosome upon growth factor stimulation, in contrast to the conventional view that PIP3 is exclusively present in the plasma membrane. Furthermore, we showed that lysosomal PIP3 originates from the plasma membrane and relies on dynamin-dependent endocytosis for lipid internalization. Thus, PIP3 can exploit dynamic trafficking pathways to access subcellular compartments and regulate signaling in a spatially selective manner.

How does puncture modality affect the risk of intraoperative bleeding during percutaneous nephrolithotomy? A prospective randomized trial

INTRODUCTION AND OBJECTIVES

To evaluate the possible effects of two different renal puncture techniques (ultrasound-assisted [US-assisted], fluoroscopic-guided [FG]) on the intraoperative hemorrhage risk during percutaneous nephrolithotomy (PCNL).

MATERIAL AND METHODS

A total of 130 patients with Guy stone scores of 1-2 were prospectively allocated to US-assisted and FG puncture groups by simple randomization. Patients with intraoperative pelvicalyceal rupture and the ones requiring multiple accesses were excluded from the study. Apart from the puncture steps, all other steps of the PCNL procedure were performed with similar techniques by a single surgeon. Patient characteristics, operative data, and postoperative outcomes were compared.

RESULTS

A total of 10 patients were excluded from the study due to intraoperative complications after puncture. Patient demographics and stone characteristics were similar between the two groups (p > 0.05). Mean hemoglobin drop was meaningfully greater in the FG group (1.7 g/dL) when compared with US-assisted group (1.3 g/dL) (p < 0.01). The mean duration of radiation exposure was significantly higher for the FG (p < 0.001). Total operative time, number of attempts for a successful puncture, length of hospital stay, and stone free rates were similar between the groups (p > 0.05). In addition, the remaining complications classified according to the modified Clavien-Dindo grading system were similar between groups (p > 0.05).

CONCLUSION

US-assisted puncture provides significantly decreased level of hemoglobin drop and radiation exposure time when compared with FG.

Molecular Spies in Action: Genetically Encoded Fluorescent Biosensors Light up Cellular Signals

Cellular function is controlled through intricate networks of signals, which lead to the myriad pathways governing cell fate. Fluorescent biosensors have enabled the study of these signaling pathways in living systems across temporal and spatial scales. Over the years there has been an explosion in the number of fluorescent biosensors, as they have become available for numerous targets, utilized across spectral space, and suited for various imaging techniques. To guide users through this extensive biosensor landscape, we discuss critical aspects of fluorescent proteins for consideration in biosensor development, smart tagging strategies, and the historical and recent biosensors of various types, grouped by target, and with a focus on the design and recent applications of these sensors in living systems.

Deep Learning Assisted Plasmonic Dark-Field Microscopy for Super-Resolution Label-Free Imaging

Dark-field microscopy (DFM) is a widely used imaging tool, due to its high-contrast capability in imaging label-free specimens. Traditional DFM requires optical alignment to block the oblique illumination, and the resolution is diffraction-limited to the wavelength scale. In this work, we present deep-learning assisted plasmonic dark-field microscopy (DAPD), which is a single-frame super-resolution method using plasmonic dark-field (PDF) microscopy and deep-learning assisted image reconstruction. Specifically, we fabricated a designed PDF substrate with surface plasmon polaritons (SPPs) illuminating specimens on the substrate. Dark field images formed by scattered light from the specimen are further processed by a pretrained convolutional neural network (CNN) using a simulation dataset based on the designed substrate and parameters of the detection optics. We demonstrated a resolution enhancement of 2.8 times on various label-free objects with a large potential for future improvement. We highlight our technique as a compact alternative to traditional DFM with a significantly enhanced spatial resolution.

Determination of healthy lifestyle behaviors and related factors in university students: An observational study

It is important for students to acquire and maintain healthy lifestyle behaviors during university education. This study investigates healthy lifestyle behaviors and related factors in university students. A total of 869 associate degree students participated in the study. Data were collected with the Data Registration Form created by the researchers and the Health Promotion Lifestyle Profile-II (HPLP-II). The mean HPLP-II total score of the study group was 127.9±19.9. Students who stay with their families, whose economic status and general health perceptions are good/very good, and who do not smoke had higher health responsibility scores (p<0.05). The mean physical activity scores of students who were male, whose parents had higher education, and who had a good/very good general health perception were higher (p<0.05). The nutrition scores of the students who were studying in the second grade, who were staying with their families, who were non-smokers, who were overweight and obese, and who had a good/very good general health perception were found to be higher (p<0.05). Those with good/very good general health perception had higher interpersonal relations and personal development scores, and female students had higher interpersonal relations scores (p<0.05). The stress management scores of the second-grade students with good/very good general health perception were higher (p<0.05). It is important to implement lifestyle interventions to improve the health of university students. Considering socio-demographic factors in health promotion programs to be implemented may help develop healthy lifestyle behaviors.

Visualization of Subcellular mTOR Complex 1 Activity with a FRET-Based Sensor (TORCAR)

The mechanistic target of rapamycin complex 1 (mTORC1) is a nutrient-sensing complex that integrates inputs from several pathways to promote cell growth and proliferation. mTORC1 localizes to many cellular compartments, including the nucleus, lysosomes, and plasma membrane. However, little is known about the spatial regulation of mTORC1 and the specific functions of mTORC1 at these locations. To address these questions, we previously developed a Förster resonance energy transfer (FRET)-based mTORC1 activity reporter (TORCAR) to visualize the dynamic changes in mTORC1 activity within live cells. Here, we describe a detailed protocol for using subcellularly targeted TORCAR constructs to investigate subcellular mTORC1 activities via live-cell fluorescence microscopy.