Analysis of Influencing Factors on the Occurrence and Development of Gastric Cancer in High-Incidence Areas of Digestive Tract Tumors Based on High Methylation of GPX3 Gene

Stomach cancer is the second largest cause of cancer-related mortality globally, and it continues to be a reason for worry today. Inhalation of the stomach cancer risk factor H. pylori produces large levels of reactive oxygen species (ROS). When combined with glutathione reductase, glutathione peroxidase 3 (GPX3) catalyzes the reduction of hydrogen peroxide and lipid peroxides. To get a better understanding of the GPX3 gene’s role in the illness, the researchers used quantitative real-time RT-PCR to examine the gene’s expression and regulation in gastric cancer cell lines, original gastric cancer samples, and 45 normal stomach mucosa adjacent to malignancies. According to the research, GPX3 expression was decreased or silenced in eight of nine cancer cell lines and 83 percent of gastric cancer samples (90/108) as compared to normal gastric tissues in the vicinity of the tumor ( P < 0.0001 ). It was found that 60 percent of stomach cancer samples exhibited DNA hypermethylation after analyzing the GPX3 promoter ( P = 0.007 ) (a methylation level of more than 10 percent, as measured by bisulfite pyrosequencing). In stomach tumors, we found a statistically significant reduction in the amount of GPX3 DNA copies ( P < 0.001 ). The gene expression of SNU1 and MKN28 cells was restored after treatment with 5-Aza-2′ Deoxycytidine to reduce GPX3 promoter methylation. Genetic and epigenetic alterations lead GPX3 to be dysfunctional in gastric cancer. This indicates that the systems that regulate ROS have been disrupted, and GPX3 may be implicated in the development of gastric cancer, as shown by our results when evaluated alone and in combination.

COVID-19: a trigger for severe thrombotic microangiopathy in a patient with complement gene variant

The evidence regarding thrombotic microangiopathy (TMA) related to Coronavirus Infectious Disease 2019 (COVID-19) in patients with complement gene mutations as a cause of acute kidney injury (AKI) are limited. We presented a case of a 23-year-old male patient admitted with an asymptomatic form of COVID-19, but with uncontrolled hypertension and AKI. Kidney biopsy showed severe lesions of TMA. In evolution patient had persistent microangiopathic hemolytic anemia, decreased level of haptoglobin and increased LDH level. Decreased complement C3 level and the presence of schistocytes were found for the first time after biopsy. Kidney function progressively decreased and the patient remained hemodialysis dependent. Complement work-up showed a heterozygous variant with unknown significance in complement factor I (CFI) c.-13G>A, affecting the 5' UTR region of the gene. In addition, the patient was found to be heterozygous for the complement factor H (CFH) H3 haplotype (involving the rare alleles of c.-331C>T, Q672Q and E936D polymorphisms) reported as a risk factor of atypical hemolytic uremic syndrome. This case of AKI associated with severe TMA and secondary hemolytic uremic syndrome highlights the importance of genetic risk modifiers in the alternative pathway dysregulation of the complement in the setting of COVID-19, even in asymptomatic forms.

Associations of Single-Nucleotide Polymorphisms in Slovenian Patients with Acute Central Serous Chorioretinopathy

Central serous chorioretinopathy (CSC) is a chorioretinal disease that usually affects the middle-aged population and is characterised by a thickened choroid, retinal pigment epithelium detachment, and subretinal fluid with a tendency towards spontaneous resolution. We investigated 13 single-nucleotide polymorphisms (SNPs) in 50 Slovenian acute CSC patients and 71 healthy controls in Complement Factor H (CFH), Nuclear Receptor Subfamily 3 Group C Member 2 (NR3C2), Cadherin 5 (CDH5) Age-Related Maculopathy Susceptibility 2 (ARMS2), TNF Receptor Superfamily Member 10a (TNFRSF10A), collagen IV alpha 3 (COL4A3) and collagen IV alpha 4 (COL4A4) genes using high-resolution melt analysis. Statistical calculations revealed significant differences in genotype frequencies for CFH rs1329428 (p = 0.042) between investigated groups and an increased risk for CSC in patients with TC (p = 0.040) and TT (p = 0.034) genotype. Genotype–phenotype correlation analysis revealed that CSC patients with CC genotype in CFH rs3753394 showed a higher tendency for spontaneous CSC episode resolution at 3 months from the disease onset (p = 0.0078), which could indicate clinical significance of SNP testing in CSC patients. Bioinformatics analysis of the non-coding polymorphisms showed alterations in transcription factor binding motifs for CFH rs3753394, CDH5 rs7499886 and TNFRSF10A rs13278062. No association of collagen IV polymorphisms with CSC was found in this study.

Dysregulation of complement factor H in juvenile-onset systemic lupus erythematosus patients

Objectives: This study aims to evaluate the expression pattern of factor H in peripheral blood and the frequency of factor H autoantibodies in plasma of juvenile-onset systemic lupus erythematosus (jSLE) patients compared to healthy controls. Patients and methods: Between March 2019 and October 2019, a total of 30 healthy individuals (3 males, 27 females; mean age: 26±7.4 years; range, 18 to 40 years) and 65 jSLE patients (age of onset ≤16 years) (2 males, 63 females; mean age: 23.4±7 years; range, 15 to 38 years) were included. Factor H expression pattern was examined in blood of all subjects using quantitative real-time polymerase chain reaction and the frequency of factor H autoantibodies was estimated in plasma using enzyme-linked immunosorbent assay. Results: Factor H expression was significantly downregulated in jSLE patients compared to healthy controls (p<0.01). A significant underexpression of factor H was observed in jSLE patients with nephritis compared to those without nephritis (p<0.03), while there was no association of factor H expression levels with any of the other clinical and serological features, disease activity or disease damage index of patients. Only 5% of jSLE patients were positive for factor H autoantibodies without any correlations with the clinical data or disease activity of patients. Conclusion: Our study results suggest that factor H expression can be dysregulated in jSLE patients.

Pediatric Atypical Hemolytic Uremic Syndrome Advances

Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by dysregulation of the alternate pathway. The diagnosis of aHUS is one of exclusion, which complicates its early detection and corresponding intervention to mitigate its high rate of mortality and associated morbidity. Heterozygous mutations in complement regulatory proteins linked to aHUS are not always phenotypically active, and may require a particular trigger for the disease to manifest. This list of triggers continues to expand as more data is aggregated, particularly centered around COVID-19 and pediatric vaccinations. Novel genetic mutations continue to be identified though advancements in technology as well as greater access to cohorts of interest, as in diacylglycerol kinase epsilon (DGKE). DGKE mutations associated with aHUS are the first non-complement regulatory proteins associated with the disease, drastically changing the established framework. Additional markers that are less understood, but continue to be acknowledged, include the unique autoantibodies to complement factor H and complement factor I which are pathogenic drivers in aHUS. Interventional therapeutics have undergone the most advancements, as pharmacokinetic and pharmacodynamic properties are modified as needed in addition to their as biosimilar counterparts. As data continues to be gathered in this field, future advancements will optimally decrease the mortality and morbidity of this disease in children.

Energy conversion efficiency of thermoelectric power generators with cylindrical legs

Thermoelectric power generators (TEGs) have been attracted increasing attention recently due to their capability of converting waste heat into useful electric energy without hazardous emissions. This paper develops a theoretical model to analyze the thermoelectric performance of TEGs with cylindrical legs. The influence of heat convection loss between lateral surfaces of thermoelectric legs and ambient environment on the energy conversion efficiency is investigated. For the idealized model, closed-form solutions of optimal electric current, maximum power output and maximum energy conversion efficiency are obtained, a new dimensionless impact factor H is introduced to capture the heat convection effect. The impact factor H depends on the ratio of heat conductivity to heat convection coefficient and geometry size of thermoelectric legs, as well as the temperature ratio of heat sink to hot source. The performance can be evaluated by the figure of merit, impact factor H and temperature gradient across the hot source and heat sink for a well-designed TEG with cylindrical legs. For the case of considering contact resistance, it is found that there exists an optimal leg's height for maximum energy conversion efficiency due to the heat convection on lateral surfaces of thermoelectric leg. The proposed theoretical model in this paper will be very helpful in the designing of actual TEG devices.

Homodimeric Minimal Factor H: In Vivo Tracking and Extended Dosing Studies in Factor H Deficient Mice

C3 glomerulopathy (C3G) is associated with dysregulation of the alternative pathway (AP) of complement and treatment options remain inadequate. Factor H (FH) is a potent regulator of the AP. An in-depth analysis of FH-related protein dimerised minimal (mini)-FH constructs has recently been published. This analysis showed that addition of a dimerisation module to mini-FH not only increased serum half-life but also improved complement regulatory function, thus providing a potential treatment option for C3G. Herein, we describe the production of a murine version of homodimeric mini-FH [mHDM-FH (mFH1–5^18–20^R1–2)], developed to reduce the risk of anti-drug antibody formation during long-term experiments in murine models of C3G and other complement-driven pathologies. Our analysis of mHDM-FH indicates that it binds with higher affinity and avidity to WT mC3b when compared to mouse (m)FH (mHDM-FH KD=505 nM; mFH KD=1370 nM) analogous to what we observed with the respective human proteins. The improved binding avidity resulted in enhanced complement regulatory function in haemolytic assays. Extended interval dosing studies in CFH-/- mice (5mg/kg every 72hrs) were partially effective and bio-distribution analysis in CFH-/- mice, through in vivo imaging technologies, demonstrates that mHDM-FH is preferentially deposited and remains fixed in the kidneys (and liver) for up to 4 days. Extended dosing using an AAV- human HDM-FH (hHDM-FH) construct achieved complete normalisation of C3 levels in CFH-/- mice for 3 months and was associated with a significant reduction in glomerular C3 staining. Our data demonstrate the ability of gene therapy delivery of mini-FH constructs to enhance complement regulation in vivo and support the application of this approach as a novel treatment strategy in diseases such as C3G.

Pinosylvin Extract Retinari™ Sustains Electrophysiological Function, Prevents Thinning of Retina, and Enhances Cellular Response to Oxidative Stress in NFE2L2 Knockout Mice

Chronic oxidative stress eventually leads to protein aggregation in combination with impaired autophagy, which has been observed in age-related macular degeneration. We have previously shown an effective age-related macular degeneration disease model in mice with nuclear factor-erythroid 2-related factor-2 (NFE2L2) knockout. We have also shown pinosylvin, a polyphenol abundant in bark waste, to increase human retinal pigment epithelium cell viability in vitro. In this work, the effects of commercial natural pinosylvin extract, Retinari™, were studied on the electroretinogram, optical coherence tomogram, autophagic activity, antioxidant capacity, and inflammation markers. Wild-type and NFE2L2 knockout mice were raised until the age of 14.8 ± 3.8 months. They were fed with either regular or Retinari™ chow ( 141 ± 17.0 mg/kg/day of pinosylvin) for 10 weeks before the assays. Retinari™ treatment preserved significant retinal function with significantly preserved a- and b-wave amplitudes in the electroretinogram responses. Additionally, the treatment prevented thinning of the retina in the NFE2L2 knockout mice. The NFE2L2 knockout mice showed reduced ubiquitin-tagged protein accumulation in addition to local upregulation of complement factor H and antioxidant enzymes superoxide dismutase 1 and catalase. Therefore, the treatment in the NFE2L2 KO disease model led to reduced chronic oxidative stress and sustained retinal function and morphology. Our results demonstrate that pinosylvin supplementation could potentially lower the risk of age-related macular degeneration onset and slow down its progression.

mTOR Inhibition via Rapamycin Treatment Partially Reverts the Deficit in Energy Metabolism Caused by FH Loss in RPE Cells

Age-related macular degeneration (AMD) is a complex degenerative disease of the retina with multiple risk-modifying factors, including aging, genetics, and lifestyle choices. The combination of these factors leads to oxidative stress, inflammation, and metabolic failure in the retinal pigment epithelium (RPE) with subsequent degeneration of photoreceptors in the retina. The alternative complement pathway is tightly linked to AMD. In particular, the genetic variant in the complement factor H gene (CFH), which leads to the Y402H polymorphism in the factor H protein (FH), confers the second highest risk for the development and progression of AMD. Although the association between the FH Y402H variant and increased complement system activation is known, recent studies have uncovered novel FH functions not tied to this activity and highlighted functional relevance for intracellular FH. In our previous studies, we show that loss of CFH expression in RPE cells causes profound disturbances in cellular metabolism, increases the vulnerability towards oxidative stress, and modulates the activation of pro-inflammatory signaling pathways, most importantly the NF-kB pathway. Here, we silenced CFH in hTERT-RPE1 cells to investigate the mechanism by which intracellular FH regulates RPE cell homeostasis. We found that silencing of CFH results in hyperactivation of mTOR signaling along with decreased mitochondrial respiration and that mTOR inhibition via rapamycin can partially rescue these metabolic defects. To obtain mechanistic insight into the function of intracellular FH in hTERT-RPE1 cells, we analyzed the interactome of FH via immunoprecipitation followed by mass spectrometry-based analysis. We found that FH interacts with essential components of the ubiquitin-proteasomal pathway (UPS) as well as with factors associated with RB1/E2F signalling in a complement-pathway independent manner. Moreover, we found that FH silencing affects mRNA levels of the E3 Ubiquitin-Protein Ligase Parkin and PTEN induced putative kinase (Pink1), both of which are associated with UPS. As inhibition of mTORC1 was previously shown to result in increased overall protein degradation via UPS and as FH mRNA and protein levels were shown to be affected by inhibition of UPS, our data stress a potential regulatory link between endogenous FH activity and the UPS.