Novel approach for quantification of multiple immunofluorescent signals using histograms and 2D plot profiling of whole-section panoramic images

Brief guide to immunostaining

Immunostaining is an essential biological technique that determines the localization and level of target antigen molecules using antibodies within cells or tissues. Here, we present a brief guide to immunostaining, including the principles, methods, and different types of immunostaining. This manuscript will also provide common challenges and optimization strategies. This work will be useful for researchers with basic knowledge in immunostaining.

Short-chain fatty acids in viral infection: the underlying mechanisms, opportunities, and challenges

Viral infections can cause cellular pathway derangements, cell death, and immunopathological responses, leading to host inflammation. Short-chain fatty acids (SCFAs), produced by the microbiota, have emerged as a potential therapeutic for viral infections due to their ability to modulate these processes. However, SCFAs have been reported to have both beneficial and detrimental effects, necessitating a comprehensive understanding of the underlying mechanisms. This review highlights the complex mechanisms underlying SCFAs' effects on viral infection outcomes. We also emphasize the importance of considering how SCFAs' activities may differ under diverse contexts, including but not limited to target cells with different metabolic wiring, different viral causes of infection, the target organism/cell's nutrient availability and/or energy balance, and hosts with varying microbiome compositions.

3,3',5,5'-Tetramethoxybiphenyl-4,4'diol triggers oxidative stress, metabolic changes, and apoptosis-like process by reducing the PI3K/AKT/NF-κB pathway in the NCI-H460 lung cancer cell line

Lung cancer is one of the leading causes of cancer-related deaths in men and women worldwide. Current treatments have limited efficacy, cause significant side effects, and cells can develop drug resistance. New therapeutic strategies are needed to discover alternative anticancer agents with high efficacy and low-toxicity. TMBP, a biphenyl obtained by laccase-biotransformation of 2,6-dimethoxyphenol, possesses antitumor activity against A549 adenocarcinoma cells. Without causing damage to sheep erythrocytes and mouse peritoneal macrophages of BALB/c mice. In addition to being classified as a good oral drug according to in-silico studies. This study evaluated the in-vitro cytotoxic effect of TMBP on lung-cancer cell-line NCI-H460 and reports mechanisms on immunomodulation and cell death. TMBP treatment (12.5-200 μM) inhibited cell proliferation at 24, 48, and 72 h. After 24-h treatment, TMBP at IC50 (154 μM) induced various morphological and ultrastructural changes in NCI-H460, reduced migration and immunofluorescence staining of N-cadherin and β-catenin, induced increased reactive oxygen species and nitric oxide with reduced superoxide radical-anion, increased superoxide dismutase activity and reduced glutathione reductase. Treatment also caused metabolic stress, reduced glucose-uptake, intracellular lactate dehydrogenase and lactate levels, mitochondrial depolarization, increased lipid droplets, and autophagic vacuoles. TMBP induced cell-cycle arrest in the G2/M phase, death by apoptosis, increased caspase-3/7, and reduced STAT-3 immunofluorescence staining. The anticancer effect was accompanied by decreasing PI3K, AKT, ARG-1, and NF-κB levels, and increasing iNOS. These results suggest its potential as a candidate for use in future lung anticancer drug design studies.

Laser doppler imaging - the role of poor burn perfusion in predicting healing time and guiding operative management

AIM

To identify if the proportion of poor blood flow (blue) within an LDI (Laser doppler Imaging) image of a burn independently correlates with healing time.

METHODS

Patient age, gender, burn type, and burn surface area were collected from the IBID (International Burn Injury Database). All LDI images were copied from the MoorLDI2-BI- Laser Doppler (MLDI) Scanner, onto Adobe Photoshop® version 2020 for pixel counting analysis and calculation of % TBSA (Total Body Surface Area) blue. Multiple linear regression analysis determined whether a proportional relationship was present for each parameter (age, gender, % TBSA Blue and comorbidities) with healing time.

RESULTS

110 patients with 197 burns were scanned with MLDI. Median age was 5 years (IQR 1-6). Median burn surface area was 1.5% (IQR 1-2.4). 56.4% of patients were male and patients were scanned an average of 2.68 days (SD±1.37) following burn injury. Number of physical comorbidities and age were found to have a statistically significant relationship with healing time (p = 0.03, p = 0.002). Gender and %TBSA blue did not have a statistically significant relationship with healing time (p = 0.07 and p = 0.058 respectively). We found a statistically significant difference in the mean healing time between burns with and without blue (3.43 weeks vs. 2.80 weeks, p = 0.0001). % TBSA Blue was more than four times higher in the operated group (0.48% vs. 0.11%) and was shown to have a statistically significant relationship with decision to operate (p = 0.027). Positive predictive value for the presence of blue on operative rate was 71.6%. Age, gender and number of comorbidities did not have a statistically significant influence on operative rate (p = 0.07, p = 0.50 and p = 0.49).

CONCLUSION

% TBSA blue was not found to be a reliable independent indicator of burn healing time, but the presence of blue within an LDI image, advanced patient age and increased number of comorbidities did have a statistically significant relationship with healing time. This suggests their standardised inclusion into management decisions regarding intermediate depth burns is warranted.

Endothelial CYP2J2 overexpression restores the BRB via METTL3-mediated ANXA1 upregulation

Blood-retinal barrier (BRB) breakdown is responsible for multiple ocular diseases, such as diabetic retinopathy, age-related macular degeneration, and retinal vascular occlusive diseases. Increased vascular permeability contributes to vasogenic edema and tissue damage, with consequent adverse effects on vision. Herein, we found that endothelial CYP2J2 overexpression maintained BRB integrity after ischemia-reperfusion injury and consequently protected against retinal ganglion cell loss. Oxidative stress repressed endothelial ANXA1 expression in vivo and in vitro. CYP2J2 upregulated methyltransferase-like 3 (METTL3) expression and hence promoted ANXA1 translation via ANXA1 m⁶ A modification in endothelium under oxidative stress. CYP2J2 maintained the distribution of endothelial tight junctions and adherens junctions in an ANXA1-dependent manner. Endothelial ANXA1 plays an indispensable role in vascular homeostasis and stabilization during development. Endothelial ANXA1 deletion disrupted retinal vascular perfusion as well as BRB integrity. CYP2J2 metabolites restored BRB integrity in the presence of ANXA1. Our findings identified the CYP2J2-METTL3-ANXA1 pathway as a potential therapeutic target for relieving BRB impairments.

Heparan Sulfate Glycosaminoglycan Is Predicted to Stabilize Inflammatory Infiltrate Formation and RANKL/OPG Ratio in Severe Periodontitis in Humans

Since chronically inflamed periodontal tissue exhibits extracellular matrix (ECM) degradation, the possible alternative to standard periodontitis treatment is to restore ECM by supplementing its components, including heparan sulfate glycosaminoglycan (HS GAG). Supplementation of the degraded ECM with synthetic derivatives of HS GAGs has been shown to be effective for periodontal tissue regeneration in experimental animal models of periodontitis. However, the potential of HS GAG supplementation for the treatment of periodontal disease in humans is still unknown. Here, we used a statistical model to investigate the role of HS GAG on inflammatory infiltrate formation and alveolar bone resorption in humans with severe periodontitis. The model was based on data from immunofluorescence staining (IF) of human gingiva samples, and reconstruction of a subset of HS GAG -related proteins from STRING reactome database. According to predictions, increased expression of native HS GAG might stabilize the accumulation of gingival inflammatory infiltrate (represented by the general inflammatory cell marker CD45) and alveolar bone resorption (represented by Receptor Activator of Nuclear ΚΒ ligand (RANKL) and osteoprotegerin (OPG) ratio) but could not restore them to healthy tissue levels. Therefore, supplementation of native HS GAG may be of limited benefits for the treatment of sever periodontitis in humans.

Modification of gingival proteoglycans by reactive oxygen species: potential mechanism of proteoglycan degradation during periodontal diseases

Reactive oxygen species (ROS) overproduction and oxidative stress are increasingly being implicated in the extracellular matrix (ECM) degradation associated with chronic inflammatory conditions, such as periodontal diseases. The present study investigated the effects of ROS exposure on the proteoglycans of gingival tissues, utilizing an in vitro model system comprised of supra-physiological oxidant concentrations, to ascertain whether gingival proteoglycan modification and degradation by ROS contributed to the underlying mechanisms of ECM destruction during active gingivitis. Proteoglycans were purified from ovine gingival tissues and exposed to increasing H₂O₂ concentrations or a hydroxyl radical (·OH) flux for 1 h or 24 h, and ROS effects on proteoglycan core proteins and sulfated glycosaminoglycan (GAG) chains were assessed. ROS were capable of degrading gingival proteoglycans, with ·OH species inducing greater degradative effects than H₂O₂ alone. Degradative effects were particularly manifested as amino acid modification, core protein cleavage, and GAG chain depolymerization. Proteoglycan core proteins were more susceptible to degradation than GAG chains with H₂O₂ alone, although core proteins and GAG chains were both extensively degraded by ·OH species. Proteoglycan exposure to ·OH species for 24 h induced significant core protein amino acid modification, with decreases in glutamate, proline, isoleucine, and leucine; and concomitant increases in serine, glycine, and alanine residues. As clinical reports have previously highlighted proteoglycan core protein degradation during chronic gingivitis, whereas their sulfated GAG chains remain relatively intact, these findings potentially provide further evidence to implicate ROS in the pathogenesis of active gingivitis, complementing the enzymic mechanisms of periodontal tissue destruction already established.