Activation Of Molecular Pathways Research Articles

Personalized targeted therapy prescription in colorectal cancer using algorithmic analysis of RNA sequencing data

Background:Overall survival of advanced colorectal cancer (CRC) patients remains poor, and gene expression analysis could potentially complement detection of clinically relevant mutations to personalize CRC treatments.Methods:We performed RNA sequencing of formalin-fixed, paraffin-embedded (FFPE) cancer tissue samples of 23 CRC patients and interpreted the data obtained using bioinformatic method Oncobox for expression-based rating of targeted therapeutics. Oncobox ranks cancer drugs according to the efficiency score calculated using target genes expression and molecular pathway activation data. The patients had primary and metastatic CRC with metastases in liver, peritoneum, brain, adrenal gland, lymph nodes and ovary. Two patients had mutations in NRAS, seven others had mutated KRAS gene. Patients were treated by aflibercept, bevacizumab, bortezomib, cabozantinib, cetuximab, crizotinib, denosumab, panitumumab and regorafenib as monotherapy or in combination with chemotherapy, and information on the success of totally 39 lines of therapy was collected.Results:Oncobox drug efficiency score was effective biomarker that could predict treatment outcomes in the experimental cohort (AUC 0.77 for all lines of therapy and 0.91 for the first line after tumor sampling). Separately for bevacizumab, it was effective in the experimental cohort (AUC 0.87) and in 3 independent literature CRC datasets, n = 107 (AUC 0.84–0.94). It also predicted progression-free survival in univariate (Hazard ratio 0.14) and multivariate (Hazard ratio 0.066) analyses. Difference in AUC scores evidences importance of using recent biosamples for the prediction quality.Conclusion:Our results suggest that RNA sequencing analysis of tumor FFPE materials may be helpful for personalizing prescriptions of targeted therapeutics in CRC.

Guidance landscapes unveiled by quantitative proteomics to control reinnervation in adult visual system

In the injured adult central nervous system (CNS), activation of pro-growth molecular pathways in neurons leads to long-distance regeneration. However, most regenerative fibers display guidance defects, which prevent reinnervation and functional recovery. Therefore, the molecular characterization of the proper target regions of regenerative axons is essential to uncover the modalities of adult reinnervation. In this study, we use mass spectrometry (MS)-based quantitative proteomics to address the proteomes of major nuclei of the adult visual system. These analyses reveal that guidance-associated molecules are expressed in adult visual targets. Moreover, we show that bilateral optic nerve injury modulates the expression of specific proteins. In contrast, the expression of guidance molecules remains steady. Finally, we show that regenerative axons are able to respond to guidance cues ex vivo, suggesting that these molecules possibly interfere with brain target reinnervation in adult. Using a long-distance regeneration model, we further demonstrate that the silencing of specific guidance signaling leads to rerouting of regenerative axons in vivo. Altogether, our results suggest ways to modulate axon guidance of regenerative neurons to achieve circuit repair in adult.

The Plasma Oxylipin Signature Provides a Deep Phenotyping of Metabolic Syndrome Complementary to the Clinical Criteria.

Metabolic syndrome (MetS) is a complex condition encompassing a constellation of cardiometabolic abnormalities. Oxylipins are a superfamily of lipid mediators regulating many cardiometabolic functions. Plasma oxylipin signature could provide a new clinical tool to enhance the phenotyping of MetS pathophysiology. A high-throughput validated mass spectrometry method, allowing for the quantitative profiling of over 130 oxylipins, was applied to identify and validate the oxylipin signature of MetS in two independent nested case/control studies involving 476 participants. We identified an oxylipin signature of MetS (coined OxyScore), including 23 oxylipins and having high performances in classification and replicability (cross-validated AUCROC of 89%, 95% CI: 85–93% and 78%, 95% CI: 72–85% in the Discovery and Replication studies, respectively). Correlation analysis and comparison with a classification model incorporating the MetS criteria showed that the oxylipin signature brings consistent and complementary information to the clinical criteria. Being linked with the regulation of various biological processes, the candidate oxylipins provide an integrative phenotyping of MetS regarding the activation and/or negative feedback regulation of crucial molecular pathways. This may help identify patients at higher risk of cardiometabolic diseases. The oxylipin signature of patients with metabolic syndrome enhances MetS phenotyping and may ultimately help to better stratify the risk of cardiometabolic diseases.

Night vision restored in days after decades of congenital blindness

SummarySignaling of vision to the brain starts with the retinal phototransduction cascade which converts visible light from the environment into chemical changes. Vision impairment results when mutations inactivate proteins of the phototransduction cascade. A severe monogenically inherited blindness, Leber congenital amaurosis (LCA), is caused by mutations in the GUCY2D gene, leading to a molecular defect in the production of cyclic GMP, the second messenger of phototransduction. We studied two patients with GUCY2D-LCA who were undergoing gene augmentation therapy. Both patients had large deficits in rod photoreceptor-based night vision before intervention. Within days of therapy, rod vision in both patients changed dramatically; improvements in visual function and functional vision in these hyper-responding patients reached more than 3 log10 units (1000-fold), nearing healthy rod vision. Quick activation of the complex molecular pathways from retinal photoreceptor to visual cortex and behavior is thus possible in patients even after being disabled and dormant for decades.

A translational genomics approach identifies IL10RB as the top candidate gene target for COVID-19 susceptibility

Recent efforts have identified genetic loci that are associated with coronavirus disease 2019 (COVID-19) infection rates and disease outcome severity. Translating these genetic findings into druggable genes that reduce COVID-19 host susceptibility is a critical next step. Using a translational genomics approach that integrates COVID-19 genetic susceptibility variants, multi-tissue genetically regulated gene expression (GReX), and perturbagen signatures, we identified IL10RB as the top candidate gene target for COVID-19 host susceptibility. In a series of validation steps, we show that predicted GReX upregulation of IL10RB and higher IL10RB expression in COVID-19 patient blood is associated with worse COVID-19 outcomes and that in vitro IL10RB overexpression is associated with increased viral load and activation of disease-relevant molecular pathways.

Roles and regulation of histone acetylation in hepatocellular carcinoma.

Hepatocellular Carcinoma (HCC) is the most frequent malignant tumor of the liver, but its prognosis is poor. Histone acetylation is an important epigenetic regulatory mode that modulates chromatin structure and transcriptional status to control gene expression in eukaryotic cells. Generally, histone acetylation and deacetylation processes are controlled by the opposing activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). Dysregulation of histone modification is reported to drive aberrant transcriptional programmes that facilitate liver cancer onset and progression. Emerging studies have demonstrated that several HDAC inhibitors exert tumor-suppressive properties via activation of various cell death molecular pathways in HCC. However, the complexity involved in the epigenetic transcription modifications and non-epigenetic cellular signaling processes limit their potential clinical applications. This review brings an in-depth view of the oncogenic mechanisms reported to be related to aberrant HCC-associated histone acetylation, which might provide new insights into the effective therapeutic strategies to prevent and treat HCC.

Downregulation of oxytocin-related genes in periodontitis.

Periodontitis is a common oral disorder leading to tooth loss in both developed and developing regions of the world. This multifactorial condition is related to the abnormal activity of several molecular pathways, among them are oxytocin-related pathways. In this study, we enrolled 26 patients and 28 controls and assessed the expression of four oxytocin-related genes, namely, FOS, ITPR, RCAN1, and RGS2, in circulation and affected tissues of enrolled individuals using real-time PCR. Expression of FOS was downregulated in total periodontitis tissues compared with total control tissues [ratio of mean expression (RME) = 0.23, P-value = 0.03]. Expression of FOS was also lower in total blood samples of patients compared with total controls. Expression of ITPR was downregulated in total periodontitis tissues compared with total control tissues (RME = 0.16, P-value = 0.01). Moreover, the expression of ITPR was reduced in total blood samples of patients compared with controls (RME = 0.25, P-value = 0.03). Expression of RCAN1 was downregulated in total periodontitis tissues compared with total control tissues (RME = 0.17, P-value = 0.01). However, the expression of RCAN1 was not different in blood samples of affected vs. unaffected individuals. Finally, the expression of RGS2 was lower in total periodontitis tissues compared with total control tissues (RME = 0.24, P-value = 0.01) and in total blood samples of affected individuals compared with controls (RME = 0.42, P-value = 0.05). This study provides data about the association between expressions of oxytocin-related genes and the presence of periodontitis. Future studies are needed to unravel the mechanistic links and find the correlation between expressions of these genes and the pathological stage of periodontitis.

Mast Cells and Vitamin D Status: A Clinical and Biological Link in the Onset of Allergy and Bone Diseases.

The immune system is made up by an extremely composite group of cells, whose regulated and harmonious activity is fundamental to maintain health. The mast cells are an essential effector of inflammatory response which is characterized by a massive release of mediators accumulated in cytoplasmic secretory granules. However, beyond the effects on immune response, mast cells can modify bone metabolism and are capable of intervening in the genesis of pathologies such as osteoporosis and osteopenia. Vitamin D is recognized to induce changes in bone metabolism, but it is also able to influence immune response, suppressing mast cell activation and IgE synthesis from B cells and increasing the number of dendritic cells and IL-10-generating regulatory T cells. Vitamin D deficit has been reported to worsen sensitization and allergic manifestations in several different experimental models. However, in clinical situations, contradictory findings have been described concerning the correlation between allergy and vitamin D deficit. The aim of this review was to analyze the close relationships between mast cells and vitamin D, which contribute, through the activation of different molecular or cellular activation pathways, to the determination of bone pathologies and the onset of allergic diseases.

Endophytic bacterium Bacillus aryabhattai induces novel transcriptomic changes to stimulate plant growth.

In nature, plants interact with a wide range of microorganisms, and most of these microorganisms could induce growth through the activation of important molecular pathways. The current study evaluated whether the endophytic bacterium Bacillus aryabhattai encourages plant growth and the transcriptional changes that might be implicated in this effect. The endophytic bacterium promotes the growth of Arabidopsis and tobacco plants. The transcriptional changes in Arabidopsis plants treated with the bacterium were also identified, and the results showed that various genes, such as cinnamyl alcohol dehydrogenase, apyrase, thioredoxin H8, benzaldehyde dehydrogenase, indoleacetaldoxime dehydratase, berberine bridge enzyme-like and gibberellin-regulated protein, were highly expressed. Also, endophytic bacterial genes, such as arginine decarboxylase, D-hydantoinase, ATP synthase gamma chain and 2-hydroxyhexa-2,4-dienoate hydratase, were activated during the interaction. These findings demonstrate that the expression of novel plant growth-related genes is induced by interaction with the endophytic bacterium B. aryabhattai and that these changes may promote plant growth in sustainable agriculture.

Subtype of Neuroblastoma Cells with High KIT Expression Are Dependent on KIT and Its Knockdown Induces Compensatory Activation of Pro-Survival Signaling.

Neuroblastoma (NB) is a pediatric cancer with high clinical and molecular heterogeneity, and patients with high-risk tumors have limited treatment options. Receptor tyrosine kinase KIT has been identified as a potential marker of high-risk NB and a promising target for NB treatment. We investigated 19,145 tumor RNA expression and molecular pathway activation profiles for 20 cancer types and detected relatively high levels of KIT expression in NB. Increased KIT expression was associated with activation of cell survival pathways, downregulated apoptosis induction, and cell cycle checkpoint control pathways. KIT knockdown with shRNA encoded by lentiviral vectors in SH-SY5Y cells led to reduced cell proliferation and apoptosis induction up to 50%. Our data suggest that apoptosis induction was caused by mitotic catastrophe, and there was a 2-fold decrease in percentage of G2-M cell cycle phase after KIT knockdown. We found that KIT knockdown in NB cells leads to strong upregulation of other pro-survival growth factor signaling cascades such as EPO, NGF, IL-6, and IGF-1 pathways. NGF, IGF-1 and EPO were able to increase cell proliferation in KIT-depleted cells in an ERK1/2-dependent manner. Overall, we show that KIT is a promising therapeutic target in NB, although such therapy efficiency could be impeded by growth factor signaling activation.

Fibroblast-Induced Paradoxical PI3K Pathway Activation in PTEN-Competent Colorectal Cancer: Implications for Therapeutic PI3K/mTOR Inhibition.

PurposeTumor-microenvironment interactions are important determinants of drug resistance in colorectal cancer (CRC). We, therefore, set out to understand how interactions between genetically characterized CRC cells and stromal fibroblasts might influence response to molecularly targeted inhibitors.TechniquesSensitivity to PI3K/AKT/mTOR pathway inhibitors of CRC cell lines, with known genetic background, was investigated under different culture conditions [serum-free medium, fibroblasts’ conditioned medium (CM), direct co-culture]. Molecular pathway activation was monitored using Western Blot analysis. Immunoprecipitation was used to detect specific mTOR complex activation. Immunofluorescence was used to analyze cellular PTEN distribution, while different mutant PTEN plasmids were used to map the observed function to specific PTEN protein domains.ResultsExposure to fibroblast-CM resulted in increased growth-inhibitory response to double PI3K/mTOR inhibitors in PTEN-competent CRC cell lines harboring KRAS and PI3K mutations. Such functional effect was attributable to fibroblast-CM induced paradoxical PI3K/mTORC1 pathway activation, occurring in the presence of a functional PTEN protein. At a molecular level, fibroblast-CM induced C-tail phosphorylation and cytoplasmic redistribution of the PTEN protein, thereby impairing its lipid phosphatase function and favored the formation of active, RAPTOR-containing, mTORC1 complexes. However, PTEN’s lipid phosphatase function appeared to be dispensable, while complex protein-protein interactions, also involving PTEN/mTOR co-localization and subcellular distribution, were crucial for both mTORC1 activation and sensitivity to double PI3K/mTOR inhibitors.Data InterpretationMicroenvironmental cues, in particular soluble factors produced by stromal fibroblasts, profoundly influence PI3K pathway signaling and functional response to specific inhibitors in CRC cells, depending on their mutational background and PTEN status.

Genomic Validation of Endometrial Cancer Patient-Derived Xenograft Models as a Preclinical Tool.

Endometrial cancer (EC) is the second most frequent gynecological cancer worldwide. Although improvements in EC classification have enabled an accurate establishment of disease prognosis, women with a high-risk or recurrent EC face a dramatic situation due to limited further treatment options. Therefore, new strategies that closely mimic the disease are required to maximize drug development success. Patient-derived xenografts (PDXs) are widely recognized as a physiologically relevant preclinical model. Hence, we propose to molecularly and histologically validate EC PDX models. To reveal the molecular landscape of PDXs generated from 13 EC patients, we performed histological characterization and whole-exome sequencing analysis of tumor samples. We assessed the similarity between PDXs and their corresponding patient’s tumor and, additionally, to an extended cohort of EC patients obtained from The Cancer Genome Atlas (TCGA). Finally, we performed functional enrichment analysis to reveal differences in molecular pathway activation in PDX models. We demonstrated that the PDX models had a well-defined and differentiated molecular profile that matched the genomic profile described by the TCGA for each EC subtype. Thus, we validated EC PDX’s potential to reliably recapitulate the majority of histologic and molecular EC features. This work highlights the importance of a thorough characterization of preclinical models for the improvement of the success rate of drug-screening assays for personalized medicine.

Inherited Retinal Dystrophies: Role of Oxidative Stress and Inflammation in Their Physiopathology and Therapeutic Implications.

Inherited retinal dystrophies (IRDs) are a large group of genetically and clinically heterogeneous diseases characterized by the progressive degeneration of the retina, ultimately leading to loss of visual function. Oxidative stress and inflammation play fundamental roles in the physiopathology of these diseases. Photoreceptor cell death induces an inflammatory state in the retina. The activation of several molecular pathways triggers different cellular responses to injury, including the activation of microglia to eliminate debris and recruit inflammatory cells from circulation. Therapeutical options for IRDs are currently limited, although a small number of patients have been successfully treated by gene therapy. Many other therapeutic strategies are being pursued to mitigate the deleterious effects of IRDs associated with oxidative metabolism and/or inflammation, including inhibiting reactive oxygen species’ accumulation and inflammatory responses, and blocking autophagy. Several compounds are being tested in clinical trials, generating great expectations for their implementation. The present review discusses the main death mechanisms that occur in IRDs and the latest therapies that are under investigation.

Mir-675-5p supports hypoxia-induced drug resistance in colorectal cancer cells

BackgroundThe uncontrolled proliferation of cancer cells determines hypoxic conditions within the neoplastic mass with consequent activation of specific molecular pathways that allow cells to survive despite oxygen deprivation. The same molecular pathways are often the cause of chemoresistance. This study aims to investigate the role of the hypoxia-induced miR-675-5p in 5-Fluorouracil (5-FU) resistance on colorectal cancer (CRC) cells.MethodsCRC cell lines were treated with 5-Fu and incubated in normoxic or hypoxic conditions; cell viability has been evaluated by MTT assay. MiR-675-5p levels were analysed by RT-PCR and loss and gain expression of the miRNA has been obtained by the transfection of miRNA antagomir or miRNA mimic. Total protein expression of different apoptotic markers was analysed through western blot assay. MirWalk 2.0 database search engine was used to investigate the putative targets of the miR-675-5p involved in the apoptotic process. Finally, the luciferase assay was done to confirm Caspase-3 as a direct target of the miR-675-5p.ResultsOur data demonstrated that hypoxia-induced miR-675-5p counteracts the apoptotic signal induced by 5-FU, thus taking part in the drug resistance response. We showed that the apoptotic markers, cleaved PARP and cleaved caspase-3, increased combining miR-675-5p inhibition with 5-FU treatment. Moreover, we identified pro-caspase-3 among the targets of the miR-675-5p.ConclusionOur data demonstrate that the inhibition of hypoxia-induced miR-675-5p combined with 5-FU treatment can enhances drug efficacy in both prolonged hypoxia and normoxia, indicating a possible strategy to partially overcome chemoresistance.

Transglutaminase 2 inhibits the proliferation of H1 subtype influenza virus in MDCK cells

Transglutaminase 2 (TGM2) is a ubiquitous multifunctional protein, which is related to the adhesion of different cells and tumor formation. Previous studies found that TGM2 is involved in the interaction between host cells and viruses, but the effect of TGM2 on the proliferation of influenza virus in cells has not been reported. To explore the effect of TGM2 during H1N1 subtype influenza virus infection, a stable MDCK cell line with TGM2 overexpression and a knockout cell line were constructed. The mRNA and protein expression levels of NP and NS1 as well as the virus titer were measured at 48 hours after pot-infection with H1N1 subtype influenza virus. The results showed that overexpression of TGM2 effectively inhibited the expression of NP and NS1 genes of H1N1 subtype influenza virus, while knockout of TGM2 up-regulated the expression of the NP and NS1 genes, and the expression of the NP at protein level was consistent with that at mRNA level. Virus proliferation curve showed that the titer of H1N1 subtype influenza virus decreased significantly upon TGM2 overexpression. On the contrary, the virus titer in TGM2 knockout cells reached the peak at 48 h, which further proved that TGM2 was involved in the inhibition of H1N1 subtype influenza virus proliferation in MDCK cells. By analyzing the expression of genes downstream of influenza virus response signaling pathway, we found that TGM2 may inhibit the proliferation of H1N1 subtype influenza virus by promoting the activation of JAK-STAT molecular pathway and inhibiting RIG-1 signaling pathway. The above findings are of great significance for revealing the mechanism underlying the interactions between host cells and virus and establishing a genetically engineering cell line for high-yield influenza vaccine production of influenza virus.

Ligand-Gated Ion Channels as Targets for Treatment and Management of Cancers.

Ligand-gated ion channels are an ionotropic receptor subtype characterized by the binding of an extracellular ligand, followed by the transient passage of ions through a transmembrane pore. Ligand-gated ion channels are commonly subcategorized into three superfamilies: purinoreceptors, glutamate receptors, and Cys-loop receptors. This classification is based on the differing topographical morphology of the receptors, which in turn confers functional differences. Ligand-gated ion channels have a diverse spatial and temporal expression which implicate them in key cellular processes. Given that the transcellular electrochemical gradient is finely tuned in eukaryotic cells, any disruption in this homeostasis can contribute to aberrancies, including altering the activity of pro-tumorigenic molecular pathways, such as the MAPK/ERK, RAS, and mTOR pathways. Ligand-gated ion channels therefore serve as a potential targetable system for cancer therapeutics. In this review, we analyze the role that each of the three ligand-gated ion channel superfamilies has concerning tumor proliferation and as a target for the treatment of cancer symptomatology.

Fucoidan (Undaria pinnatifida)/Polydopamine Composite-Modified Surface Promotes Osteogenic Potential of Periodontal Ligament Stem Cells.

Fucoidan, a marine-sulfated polysaccharide derived from brown algae, has been recently spotlighted as a natural biomaterial for use in bone formation and regeneration. Current research explores the osteoinductive and osteoconductive properties of fucoidan-based composites for bone tissue engineering applications. The utility of fucoidan in a bone tissue regeneration environment necessitates a better understanding of how fucoidan regulates osteogenic processes at the molecular level. Therefore, this study designed a fucoidan and polydopamine (PDA) composite-based film for use in a culture platform for periodontal ligament stem cells (PDLSCs) and explored the prominent molecular pathways induced during osteogenic differentiation of PDLSCs through transcriptome profiling. Characterization of the fucoidan/PDA-coated culture polystyrene surface was assessed by scanning electron microscopy and X-ray photoelectron spectroscopy. The osteogenic differentiation of the PDLSCs cultured on the fucoidan/PDA composite was examined through alkaline phosphatase activity, intracellular calcium levels, matrix mineralization assay, and analysis of the mRNA and protein expression of osteogenic markers. RNA sequencing was performed to identify significantly enriched and associated molecular networks. The culture of PDLSCs on the fucoidan/PDA composite demonstrated higher osteogenic potency than that on the control surface. Differentially expressed genes (DEGs) (n = 348) were identified during fucoidan/PDA-induced osteogenic differentiation by RNA sequencing. The signaling pathways enriched in the DEGs include regulation of the actin cytoskeleton and Ras-related protein 1 and phosphatidylinositol signaling. These pathways represent cell adhesion and cytoskeleton organization functions that are significantly involved in the osteogenic process. These results suggest that a fucoidan/PDA composite promotes the osteogenic potential of PDLSCs by activation of critical molecular pathways.

Better Agreement of Human Transcriptomic and Proteomic Cancer Expression Data at the Molecular Pathway Activation Level.

Previously, we have shown that the aggregation of RNA-level gene expression profiles into quantitative molecular pathway activation metrics results in lesser batch effects and better agreement between different experimental platforms. Here, we investigate whether pathway level of data analysis provides any advantage when comparing transcriptomic and proteomic data. We compare the paired proteomic and transcriptomic gene expression and pathway activation profiles obtained for the same human cancer biosamples in The Cancer Genome Atlas (TCGA) and the NCI Clinical Proteomic Tumor Analysis Consortium (CPTAC) projects, for a total of 755 samples of glioblastoma, breast, liver, lung, ovarian, pancreatic, and uterine cancers. In a CPTAC assay, expression levels of 15,112 protein-coding genes were profiled using the Thermo QE series of mass spectrometers. In TCGA, RNA expression levels of the same genes were obtained using the Illumina HiSeq 4000 engine for the same biosamples. At the gene level, absolute gene expression values are compared, whereas pathway-grade comparisons are made between the pathway activation levels (PALs) calculated using average sample-normalized transcriptomic and proteomic profiles. We observed remarkably different average correlations between the primary RNA- and protein expression data for different cancer types: Spearman Rho between 0.017 (p = 1.7 × 10−13) and 0.27 (p < 2.2 × 10−16). However, at the pathway level we detected overall statistically significantly higher correlations: averaged Rho between 0.022 (p < 2.2 × 10−16) and 0.56 (p < 2.2 × 10−16). Thus, we conclude that data analysis at the PAL-level yields results of a greater similarity when comparing high-throughput RNA and protein expression profiles.

Heat Shock Protein 90 as Therapeutic Target for CVDs and Heart Ageing.

Cardiovascular diseases (CVDs) are the leading cause of death globally, representing approximately 32% of all deaths worldwide. Molecular chaperones are involved in heart protection against stresses and age-mediated accumulation of toxic misfolded proteins by regulation of the protein synthesis/degradation balance and refolding of misfolded proteins, thus supporting the high metabolic demand of the heart cells. Heat shock protein 90 (HSP90) is one of the main cardioprotective chaperones, represented by cytosolic HSP90a and HSP90b, mitochondrial TRAP1 and ER-localised Grp94 isoforms. Currently, the main way to study the functional role of HSPs is the application of HSP inhibitors, which could have a different way of action. In this review, we discussed the recently investigated role of HSP90 proteins in cardioprotection, atherosclerosis, CVDs development and the involvements of HSP90 clients in the activation of different molecular pathways and signalling mechanisms, related to heart ageing.

Interaction of aging with lipoxygenase deficiency initiates hypersplenism, cardiac dysfunction, and profound leukocyte directed non-resolving inflammation.

In the process of physiological cardiac repair, splenic leukocyte-activated lipoxygenases (LOXs) are essential for the biosynthesis of specialized pro-resolving lipid mediators as a segment of an active process of acute inflammation in splenocardiac manner. In contrast, young 12/15LOX-/- mice use a compensatory mechanism that amplifies epoxyeicosatrienoic acid mediators after myocardial infarction, improving cardiac repair, function, and survival. Next, we tested whether deletion of 12/15LOX impacted the genesis of chronic inflammation in progressive aging. To test the risk factor of aging, we used the inter-organ hypothesis and assessed heart and spleen leukocyte population along with the number of inflammation markers in age-related 12/15LOX-/- aging mice (2months, 6months, 13months) and compared with C57BL/6J (WT; wild type) as controls (2months). The 12/15LOX-/- aging mice showed an age-related increase in spleen mass (hypersplenism) and decreased marginal zone area. Results suggest increased interstitial fibrosis in the heart marked with the inflammatory mediator (PGD2) level in 12/15LOX-/- aging mice than WT controls. From a cellular perspective, the quantitative measurement of immune cells indicates that heart and spleen leukocytes (CD11b+ and F4/80+ population) were reduced in 12/15LOX-/- aging mice than WT controls. At the molecular level, analyses of cytokines in the heart and spleen suggest amplified IFN-γ, with reduced COX-1, COX-2, and ALOX5 expression in the absence of 12/15LOX-derived mediators in the spleen. Thus, aging of 12/15LOX-/- mice increased spleen mass and altered spleen and heart structure with activation of multiple molecular and cellular pathways contributing to age-related integrative and inter-organ inflammation.