FLOW AND GEOMETRICAL ALTERATIONS IN RETINAL MICROVASCULATURE CORRELATED WITH THE OCCURRENCE OF DIABETIC RETINOPATHY: Evidence from a Longitudinal Study.

PURPOSE: To assess the relationship between flow and geometric parameters in optical coherence tomography angiography images and the risk of incident diabetic retinopathy (DR). METHODS: This prospective, observational cohort study recruited patients with Type 2 diabetes without DR in Guangzhou, China, and followed up annually. A commercially available optical coherence tomography angiography device (DRI OCT Triton; Topcon Inc, Tokyo, Japan) was used to obtain a variety of flow (foveal avascular zone area, vessel density, and vessel length density) and geometric (fractal dimension and blood vessel tortuosity) parameters in superficial capillary plexus (SCP) and deep capillary plexus. The odds ratio (OR) and its 95% confidence interval (CI) were calculated per 1-SD increase in each optical coherence tomography angiography parameter. RESULTS: Over a follow-up of 1 year, 182 of 1,698 participants (10.7%) developed incident DR. After adjusting for conventional risk factors and image quality score, the higher risk of DR onset was significantly associated with the reduced parafoveal vessel density of SCP (OR = 0.81; 95% CI: 0.69, 0.96; P = 0.016), reduced parafoveal vessel length density of SCP (OR = 0.73; 95% CI: 0.59, 0.90; P = 0.003), reduced fractal dimension of SCP (OR = 0.73; 95% CI: 0.61, 0.87; P < 0.001), increased blood vessel tortuosity of SCP (OR = 1.39; 95% CI: 1.18, 1.64; P < 0.001), and increased blood vessel tortuosity of deep capillary plexus (OR = 1.19; 95% CI: 1.01, 1.40; P = 0.033). CONCLUSION: Reduced vessel density and impaired vessel geometry posed higher susceptibility for DR onset in patients with Type 2 diabetes, supporting the adoption of optical coherence tomography angiography parameters as early monitoring indicators of the newly incident DR.

Oxidation of dCTP contributes to antibiotic lethality in stationary-phase mycobacteria.

Growing evidence shows that generation of reactive oxygen species (ROS) derived from antibiotic-induced metabolic perturbation contribute to antibiotic lethality. However, our knowledge of the mechanisms by which antibiotic-induced oxidative stress actually kills cells remains elusive. Here, we show that oxidation of dCTP underlies ROS-mediated antibiotic lethality via induction of DNA double-strand breaks (DSBs). Deletion of mazG-encoded 5-OH-dCTP-specific pyrophosphohydrolase potentiates antibiotic killing of stationary-phase mycobacteria, but did not affect antibiotic efficacy in exponentially growing cultures. Critically, the effect of mazG deletion on potentiating antibiotic killing is associated with antibiotic-induced ROS and accumulation of 5-OH-dCTP. Independent lines of evidence presented here indicate that the increased level of DSBs observed in the ΔmazG mutant is a dead-end event accounting for enhanced antibiotic killing. Moreover, we provided genetic evidence that 5-OH-dCTP is incorporated into genomic DNA via error-prone DNA polymerase DnaE2 and repair of 5-OH-dC lesions via the endonuclease Nth leads to the generation of lethal DSBs. This work provides a mechanistic view of ROS-mediated antibiotic lethality in stationary phase and may have broad implications not only with respect to antibiotic lethality but also to the mechanism of stress-induced mutagenesis in bacteria.

Regulations of m6A and other RNA modifications and their roles in cancer.

RNA modification is an essential component of the epitranscriptome, regulating RNA metabolism and cellular functions. Several types of RNA modifications have been identified to date; they include N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N6,2'-O-dimethyladenosine (m6Am), N4-acetylcytidine (ac4C), etc. RNA modifications, mediated by regulators including writers, erasers, and readers, are associated with carcinogenesis, tumor microenvironment, metabolic reprogramming, immunosuppression, immunotherapy, chemotherapy, etc. A novel perspective indicates that regulatory subunits and post-translational modifications (PTMs) are involved in the regulation of writer, eraser, and reader functions in mediating RNA modifications, tumorigenesis, and anticancer therapy. In this review, we summarize the advances made in the knowledge of different RNA modifications (especially m6A) and focus on RNA modification regulators with functions modulated by a series of factors in cancer, including regulatory subunits (proteins, noncoding RNA or peptides encoded by long noncoding RNA) and PTMs (acetylation, SUMOylation, lactylation, phosphorylation, etc.). We also delineate the relationship between RNA modification regulator functions and carcinogenesis or cancer progression. Additionally, inhibitors that target RNA modification regulators for anticancer therapy and their synergistic effect combined with immunotherapy or chemotherapy are discussed.

γ-secretase binding sites in aged and Alzheimer's disease human cerebrum: the choroid plexus as a putative origin of CSF Aß.

Deposition of ß -amyloid (Aß) peptides, cleavage products of ß-amyloid precursor protein (APP) by ß-secretase-1 (BACE1) and γ-secretase, is a neuropathological hallmark of Alzheimer's disease (AD). γ-Secretase inhibition is a therapeutical anti-Aß approach, although changes in the enzyme's activity in AD brain are unclear. Cerebrospinal fluid (CSF) Aß peptides are thought to derive from brain parenchyma and thus may serve as biomarkers for assessing cerebral amyloidosis and anti-Aß efficacy. The present study compared active γ-secretase binding sites with Aß deposition in aged and AD human cerebrum, and explored the possibility of Aß production and secretion by the choroid plexus (CP). The specific binding density of [(3) H]-L-685,458, a radiolabeled high-affinity γ-secretase inhibitor, in the temporal neocortex and hippocampal formation was similar for AD and control cases with similar ages and post-mortem delays. The CP in post-mortem samples exhibited exceptionally high [(3) H]-L-685,458 binding density, with the estimated maximal binding sites (Bmax) reduced in the AD relative to control groups. Surgically resected human CP exhibited APP, BACE1 and presenilin-1 immunoreactivity, and ß-site APP cleavage enzymatic activity. In primary culture, human CP cells also expressed these amyloidogenic proteins and released Aß40 and Aß42 into the medium. Overall, our results suggest that γ-secretase activity appears unaltered in the cerebrum in AD and is not correlated with regional amyloid plaque pathology. The CP appears to be a previously unrecognised non-neuronal contributor to CSF Aß, probably at reduced levels in AD.

[Adenovirus vector mediated human 14-3-3 γ gene transfer protects dopaminergic cells against rotenone-induced injury].

OBJECTIVE: To explore the protective effect of human 14-3-3 γ gene transfer on dopaminergic cells against rotenone-induced injury. METHODS: Adenovirus vector carrying the gene of 14-3-3 γ (Ad/14-3-3 γ) was employed to transfect PC12 cells. Then the cells were exposed to rotenone as a model of Parkinson's disease. Methyl thiazolyl tetrazolium (MTT) was used to assay the viability of PC12 cells. The 4',6-diamidino-2-phenylindole (DAPI) staining was used to analyze the apoptotic ratio of PC12 cells among the groups of control, Ad/14-3-3 γ, Ad-null and Rotenone. And high performance liquid chromatography (HPLC) was performed to detect the secreting functions of PC12 cells. The aggregates of α-Synuclein protein were detected under confocal microscopy. RESULTS: MTT showed that the cell absorbance A(570) of Ad/14-3-3 γ group (0.46 ± 0.09) was higher than that of Ad-null group (0.19 ± 0.08) and rotenone group (0.16 ± 0.07), but lower than that of normal control (0.63 ± 0.11), (all P < 0.01); HPLC-ECD showed that the levels of dopamine (189 ± 11) ng/ml and noradrenalin (55 ± 8) ng/ml in the culture fluid of Ad/14-3-3 γ group were higher than those of Ad-null group (79 ± 12, 38 ± 7) ng/ml and rotenone group (81 ± 13, 39 ± 7) ng/ml (all P < 0.01). DAPI staining showed that cell apoptosis ratio of group Ad/14-3-3 γ (27% ± 64%) was lower than that of group Ad-null (53% ± 10%) and rotenone group (56% ± 12%, P < 0.01), but higher than that of control group (10% ± 5%, P < 0.01). Under confocal microscopy, the aggregates of α-synuclein protein in PC12 cells were detected more in Ad-null group and rotenone group than that in Ad/14-3-3 γ group. CONCLUSION: Gene transfer of Ad/14-3-3 γ has a protective effect on dopaminergic cells against rotenone-induced injury.

Macular Choroidal Thickness and the Risk of Referable Diabetic Retinopathy in Type 2 Diabetes: A 2-Year Longitudinal Study.

Purpose: The purpose of this study was to evaluate the associations between choroidal thickness (CT) and the 2-year incidence of referable diabetic retinopathy (RDR). Methods: This was a prospective cohort study. Patients with type 2 diabetes in Guangzhou, China, aged 30 to 80 years underwent comprehensive examinations, including standard 7-field fundus photography. Macular CT was measured using a commercial swept-source optical coherence tomography (SS-OCT) device (DRI OCT Triton; Topcon, Tokyo, Japan). The relative risk (RR) with 95% confidence intervals (CIs) was used to quantify the association between CT and new-onset RDR. The prognostic value of CT was assessed using the area under the receiver operating characteristic curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Results: A total of 1345 patients with diabetes were included in the study, and 120 (8.92%) of them had newly developed RDR at the 2-year follow-up. After adjusting for other factors, the increased RDR risk was associated with greater HbA1c (RR = 1.35, 95% CI = 1.17-1.55, P < 0.001), higher systolic blood pressure (SBP; RR = 1.02, 95% CI = 1.01-1.03, P = 0.005), lower triglyceride (TG) level (RR = 0.81, 95% CI = 0.69-0.96, P = 0.015), presence of diabetic retinopathy (DR; RR = 8.16, 95% CI = 4.47-14.89, P < 0.001), and thinner average CT (RR = 0.903, 95% CI = 0.871-0.935, P < 0.001). The addition of average CT improved NRI (0.464 ± 0.096, P < 0.001) and IDI (0.0321 ± 0.0068, P < 0.001) for risk of RDR, and it also improved the AUC from 0.708 (95% CI = 0.659-0.757) to 0.761 (95% CI = 0.719-0.804). Conclusions: CT thinning measured by SS-OCT is an early imaging biomarker for the development of RDR, suggesting that alterations in CT play an essential role in DR occurrence.

Decreasing hyaluronic acid combined with drug-loaded nanoprobes improve the delivery and efficacy of chemotherapeutic drugs for pancreatic cancer.

Pancreatic cancer is one of the common malignant tumors of the digestive system, and its clinical treatment is still very challenging. Most of the pancreatic cancer chemotherapeutic drugs have poor plasma stability, low cell uptake efficiency, and are prone to developing drug resistance and toxic side effects. Besides, pancreatic cancer often has a dense extracellular matrix, which consists of collagens, hyaluronic acid, and other proteoglycans. Among them, hyaluronic acid is a key component of the dense matrix, which results in vascular compression and insufficient perfusion, and hinders the delivery of chemotherapeutic drugs. In this study, we explore using hyaluronidase in tumor-bearing mice to eliminate the hyaluronic acid barrier, to reduce blood vessel compression and reshape the tumor microenvironment. In addition, we evaluate using doxorubicin-loaded nanoprobes to improve the stability and local tumor-killing effect of the drug. The nanoprobes have the characteristics of near-infrared optical imaging, which are used to monitor the tumor size in real-time during the treatment process, and dynamically observe the tumor inhibitory effect. The results show that elimination of the hyaluronic acid barrier combined with the doxorubicin-loaded nanoprobes can greatly increase drug penetration into tumor tissue and improve the effectiveness of chemotherapy drugs. This study provides a novel strategy for the treatment of pancreatic cancer.

Housecleaning of pyrimidine nucleotide pool coordinates metabolic adaptation of nongrowing Mycobacterium tuberculosis.

The ability of Mycobacterium tuberculosis (Mtb) to adopt a slowly growing or nongrowing state within the host plays a critical role for the bacilli to persist in the face of a prolonged multidrug therapy, establish latency and sustain chronic infection. In our previous study, we revealed that genome maintenance via MazG-mediated elimination of oxidized dCTP contributes to the antibiotic tolerance of nongrowing Mtb. Here, we provide evidence that housecleaning of pyrimidine nucleotide pool via MazG coordinates metabolic adaptation of Mtb to nongrowing state. We found that the ΔmazG mutant fails to maintain a nongrowing and metabolic quiescence state under dormancy models in vitro. To investigate bacterial metabolic changes during infection, we employed RNA-seq to compare the global transcriptional response of wild-type Mtb and the ΔmazG mutant after infection of macrophages. Pathway enrichment analyses of the differentially regulated genes indicate that the deletion of mazG in Mtb not only results in DNA instability, but also perturbs pyrimidine metabolism, iron and carbon source uptake, catabolism of propionate and TCA cycle. Moreover, these transcriptional signatures reflect anticipatory metabolism and regulatory activities observed during cell cycle re-entry in the ΔmazG mutant. Taken together, these results provide evidence that pyrimidine metabolism is a metabolic checkpoint during mycobacterial adaptation to nongrowing state.

[Autopsy report of two cases with enterovirus type 71 infection brainstem encephalitis and literature review].

OBJECTIVE: To understand clinicopathologic characteristics of hand-foot-and-mouth disease. METHODS: The data of two autopsy cases with brainstem encephalitis caused by enterovirus type 71 infection were analyzed. RESULTS: The age of the two patients was younger ( < or = 3 age). The clinical course was rapidly progressive, vesicular rashes were found in one case and the other case had no rashes. Both patients had clinical manifestations of central nervous system. Rapid progression to death were preceded by the development of pulmonary edema and hemorrhage. The results of the autopsy showed that the brain and brain stem were most severely involved and there were inflammation and necrosis. There were lung edema and hemorrhage. The myocardium and other organs were not infiltrated by inflammatory cells. CONCLUSION: Hand-foot- and-mouth disease with enterovirus type 71 infection often affected central nervous system, rapid progression to death was preceded by the development of brain stem encephalitis and pulmonary edema.