Indirect Mechanisms Research Articles

The impact of rural e-commerce participation on farmers’ entrepreneurial behavior: Evidence based on CFPS data in China

The "Three Rural Issues", encompass challenges related to agriculture, farmer, and rural area, which hold significant importance in driving comprehensive rural revitalization efforts in China. Farmer entrepreneurship, as a crucial means to enhance productivity, create job opportunities, and increase residents’ income, has gradually become a key driving force in promoting rural revitalization in the new stage of development in China. With the rapid development of rural e-commerce, farmer entrepreneurship has encountered new opportunities. This study utilizes the 2020 China Family Panel Studies (CFPS) data and employs a structural equation model (SEM) to analyze the direct impact of rural e-commerce participation on farmer entrepreneurial behavior, considering factors such as human capital, social capital, and network infrastructure. This study further explores the indirect effects and mechanisms of e-commerce participation as a mediating variable and analyzes the impact and mechanisms on agricultural entrepreneurship behavior. The findings are as follows: (1) E-commerce participation significantly promotes farmer entrepreneurial behavior; (2) E-commerce participation as a mediating variable has a positive indirect effect on the relationship between social trust, network infrastructure, human capital, and farmer entrepreneurial behavior; (3) E-commerce participation has a significant positive influence on farmer entrepreneurship in the agricultural sector, and farmers with higher levels of network infrastructure and human capital have a higher probability of choosing agricultural entrepreneurship under the influence of e-commerce participation. Finally, this study provides policy recommendations in terms of infrastructure construction, entrepreneurial policy environment, and education level, aiming to optimize the situation of farmer entrepreneurship and contribute to the comprehensive promotion of rural revitalization.Overall, the research in this paper effectively combines theory and empirical evidence to outline the direct and indirect impact mechanisms of rural e-commerce participation on farmers’ entrepreneurial behavior and agriculture-related entrepreneurial behavior and to test the effects of their impacts. First, most of the existing literature deals with farmers in individual sample areas, while the sample selected in this paper is farmers in the whole country, which is relatively more generalizable; second, most of the previous studies explore the level of e-commerce in the inter-provincial or county areas, while this paper expands the empirical study of rural e-commerce on the entrepreneurial behavior of farmers and the micro-period of agricultural entrepreneurial behavior, and focuses on the impacts of the e-commerce activities of farmers on their entrepreneurial behavior.

How COVID-19 Can Damage the Heart? – Association of Cardiac Injury with COVID-19: A Narrative Review

Abstract Severe acute respiratory syndrome coronavirus 2 and its resulting disease, COVID-19, remain a significant public health concern. Cardiovascular injury is the second most common complication, following respiratory disease, encompassing conditions such as myocarditis, acute myocardial injury, acute coronary syndrome, arrhythmia, and heart failure. It presents with high-troponin levels, reduced left ventricular systolic function, and/or electrocardiographic abnormalities. Cardiac involvement is an independent risk factor for worse clinical outcomes and higher mortality, particularly in the elderly patients. The debate continues regarding whether the cardiac manifestations of COVID-19 result from direct viral infection or indirect cellular injuries. The virus attaches directly to angiotensin-converting enzyme 2 receptor, which is extensively expressed in the heart, invades myocardial tissue, and triggers an excessive inflammatory response. Indirect mechanisms stem from endothelial damage, hypercoagulability and micro-thrombosis, cytokine storm, respiratory failure and hypoxia, and autoimmunity. The pathophysiology of cardiac injury in COVID-19 patients is important to frame the main pathways and biomarkers to encourage new therapeutic trials to improve the disease prognosis and to understand the course of the disease.

ENAM Mutations Can Cause Hypomaturation Amelogenesis Imperfecta.

Amelogenesis imperfecta (AI) is a diverse group of inherited diseases featured by various presentations of enamel malformations that are caused by disturbances at different stages of enamel formation. While hypoplastic AI suggests a thickness defect of enamel resulting from aberrations during the secretory stage of amelogenesis, hypomaturation AI indicates a deficiency of enamel mineralization and hardness established at the maturation stage. Mutations in ENAM, which encodes the largest enamel matrix protein, enamelin, have been demonstrated to cause generalized or local hypoplastic AI. Here, we characterized 2 AI families with disparate hypoplastic and hypomaturation enamel defects and identified 2 distinct indel mutations at the same location of ENAM, c588+1del and c.588+1dup. Minigene splicing assays demonstrated that they caused frameshifts and truncation of ENAM proteins, p.Asn197Ilefs*81 and p.Asn197Glufs*25, respectively. In situ hybridization of Enam on mouse mandibular incisors confirmed its restricted expression in secretory stage ameloblasts and suggested an indirect pathogenic mechanism underlying hypomaturation AI. In silico analyses indicated that these 2 truncated ENAMs might form amyloid structures and cause protein aggregation with themselves and with wild-type protein through the added aberrant region at their C-termini. Consistently, protein secretion assays demonstrated that the truncated proteins cannot be properly secreted and impede secretion of wild-type ENAM. Moreover, compared to the wild-type, overexpression of the mutant proteins significantly increased endoplasmic reticulum stress and upregulated the expression of unfolded protein response (UPR)-related genes and TNFRSF10B, a UPR-controlled proapoptotic gene. Caspase, terminal deoxynucleotidyl transferase UTP nick-end labeling (TUNEL), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays further revealed that both truncated proteins, especially p.Asn197Ilefs*81, induced cell apoptosis and decreased cell survival, suggesting that the 2 ENAM mutations cause AI through ameloblast cell pathology and death rather than through a simple loss of function. This study demonstrates that an ENAM mutation can lead to generalized hypomaturation enamel defects and suggests proteinopathy as a potential pathogenesis for ENAM-associated AI.

The role of innovative human resource management practices, organizational support and knowledge worker effort in counteracting job burnout in the Polish business services sector.

This study focuses on analyzing the impact of innovative human resource management practices (IHRMP) on knowledge worker burnout, and how organizational support and employee effort help explain this relationship in the context of the business services sector. To explore the problem, investigated whether IHRMP have a significant negative impact on employee burnout, and organizational support and employee effort mediate the negative impact of IHRMP on employee burnout. A survey was conducted, collected using the computer assisted web interview method on 1000 knowledge workers employed at business services sector (BSS) organizations in Poland. The quantitative results obtained were analyzed using AMOS software to test the main statistical relationships and through structural equation modeling. The study outlines direct and indirect mechanisms to counteract perceived burnout among knowledge workers. The article contributes to the understanding of how IHRMP reduce burnout among knowledge workers and highlights the central importance of organizational support and employee effort as mediating factors against burnout in the context of high-skill, high-intensity work. The expected results in terms of application provide a proposal of measures for managers' consideration that can be implemented in the organization with a view to counteracting the incidence of burnout among BSS employees. Int J Occup Med Environ Health. 2024;37(2).

The off-target NHE1 inhibitory effect of SGLT2 inhibitors in cardiac remodeling

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors, approved for the treatment of diabetes mellitus, have gained attention for their cardioprotective effect. The exact mechanism by which SGLT-2 inhibitors exert their cardioprotective effect remains unclear. Recent studies have suggested that empagliflozin (EMPA), an SGLT inhibitor, exerts its car¬dioprotective effect by inhibiting the Na+/H+ exchanger (NHE); a group of membrane proteins that regulate intracel¬lular pH and cell volume. Increased activity and expression of NHE isoform 1 (NHE1), the predominant isoform ex¬pressed in the heart, leads to cardiac hypertrophy. Our research group investigates the indirect mechanisms by which SGLT inhibitors exert their cardioprotective effect and have demonstrated that angiotensin II (ANG)-induced hyper¬trophy of H9c2 cardiomyoblasts is accompanied with increased SGLT-1 and NHE1 protein expression; an effect which is reversed in the presence of EMPA. In addition, we demonstrated that dapagliflozin improved survival of transgenic mice expressing cardiac-specific NHE1.

Impact of digital economy on urban land green use efficiency: evidence from Chinese cities

Abstract Improving urban land green use efficiency (ULGUE) is essential for achieving the sustainable use of land resources and the high-quality economic development of cities. The digital economy has overcome spatial and locational constraints, blurred the boundaries between industries, and created a collaborative and open economic model, inevitably affecting urban land utilization. However, whether the digital economy will affect ULGUE and how such an effect would take place are still unclear. This study evaluates the digital economy and ULGUE of Chinese cities from 2011 to 2019 and systematically analyzes both the direct and indirect impact mechanisms through which the digital economy affects ULGUE. The results show that the digital economy can significantly enhance ULGUE, and these results prove to be reliable, as shown by various endogeneity treatments and robustness tests. The digital economy enhances ULGUE by optimizing the industrial structure (structural effect), increasing green technology innovation (technical effect), and agglomerating digital talent (scale effect). Moreover, land finance dependency plays an adverse moderating role in the relationship between the digital economy and ULGUE. Further heterogeneity analysis shows that the promoting effect of the digital economy on ULGUE takes full effect in the eastern cities, larger cities, and cities with high levels of digital economy development and land marketization. This paper presents recommendations for supporting the balanced and integrated development of the digital economy across regions and provides differentiated development strategies to enhance ULGUE in the context of digitization.

HCMV US2 co-opts TRC8 to degrade the endoplasmic reticulum-resident protein LMAN2L.

The human cytomegalovirus (HCMV) pUS2 glycoprotein exploits the host's endoplasmic reticulum (ER)-associated degradation (ERAD) pathway to degrade major histocompatibility complex class I (MHC-I) and prevent antigen presentation. Beyond MHC-I, pUS2 has been shown to target a range of cellular proteins for degradation, preventing their cell surface expression. Here we have identified a novel pUS2 target, ER-resident protein lectin mannose binding 2 like (LMAN2L). pUS2 expression was both necessary and sufficient for the downregulation of LMAN2L, which was dependent on the cellular E3 ligase TRC8. Given the hypothesized role of LMAN2L in the trafficking of glycoproteins, we employed proteomic plasma membrane profiling to measure LMAN2L-dependent changes at the cell surface. A known pUS2 target, integrin alpha-6 (ITGA6), was downregulated from the surface of LMAN2L-deficient cells, but not other integrins. Overall, these results suggest a novel strategy of pUS2-mediated protein degradation whereby pUS2 targets LMAN2L to impair trafficking of ITGA6. Given that pUS2 can directly target other integrins, we propose that this single viral protein may exhibit both direct and indirect mechanisms to downregulate key cell surface molecules.

Analgesic candidate adenosine A3 receptors are expressed by perineuronal peripheral macrophages in human dorsal root ganglion and spinal cord microglia.

Adenosine receptors are a family of purinergic G protein-coupled receptors that are widely distributed in bodily organs and in the peripheral and central nervous systems. Recently, antihyperalgesic actions have been suggested for the adenosine A3 receptor, and its agonists have been proposed as new neuropathic pain treatments. We hypothesized that these receptors may be expressed in nociceptive primary afferent neurons. However, RNA sequencing across species, eg, rat, mouse, dog, and human, suggests that dorsal root ganglion (DRG) expression of ADORA3 is inconsistent. In rat and mouse, Adora3 shows very weak to no expression in DRG, whereas it is well expressed in human DRG. However, the cell types in human DRG that express ADORA3 have not been delineated. An examination of DRG cell types using in situ hybridization clearly detected ADORA3 transcripts in peripheral macrophages that are in close apposition to the neuronal perikarya but not in peripheral sensory neurons. By contrast, ADORA1 was found primarily in neurons, where it is broadly expressed at low levels. These results suggest that a more complex or indirect mechanism involving modulation of macrophage and/or microglial cells may underlie the potential analgesic action of adenosine A3 receptor agonism.

Is human herpesvirus 8 infection more common in men than in women? an updated meta-analysis

BackgroundClinically, most patients with Kaposi's sarcoma (KS) are male, and several direct and indirect mechanisms may underlie this increased susceptibility in men, Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is considered to be the primary etiological agent responsible for KS. Thus, we propose the hypothesis that men are more susceptible to HHV-8 infection, leading to a higher incidence of Kaposi's sarcoma among males. A meta-analysis was conducted to evaluate the association between gender and HHV-8 seropositivity in the general population.MethodsA comprehensive literature search was performed using 6 online databases: PubMed, EMBASE, Cochrane library, Web of Science, CNKI, and Wanfang. Studies published before March 15, 2023, were included.ResultsIn all, 33 articles including 41 studies were included in the meta-analysis. In the included adult population. men had a higher risk of HHV-8 infection than did women in adult populations from all over the world (odds ratio [OR]: 1.08, 95% confidence interval [CI]: 1.01–1.15), but no differences were found in child population from all over the world (OR: 0.90, 95% CI: 0.79–1.01). There was a significant difference in HHV-8 seroprevalence between men and women in sub-Saharan Africa (SSA) adult population (OR: 1.15, 95% CI: 1.05–1.26). However, no significant differences were observed in sub-Saharan Africa (SSA) child population (OR: 0.90, 95%CI 0.78–1.03). As for other continents, the results showed no significant difference, such as the Asian population (OR: 1.03, 95%CI: 0.92–1.16). or the European and American populations (OR 1.01, 95%CI 0.87–1.17).ConclusionThere was a slight gender disparity for HHV-8 infection in the adult population. Among the adult populations from SSA and globally, men were more likely to be infected with HHV-8 than were women. However, no statistical significance was observed in the child populations from SSA and globally. In the future, the inclusion of more standardized studies may strengthen the results of this study.

KLF15-Cyp3a11 Axis Regulates Rifampicin-induced Liver Injury.

Rifampicin (RFP) has demonstrated potent antibacterial effects in the treatment of pulmonary tuberculosis. However, the serious adverse effects on the liver intensively limit the clinical usage of the drug. Deacetylation greatly reduces the toxicity of RFP but also retains its curative activity. Here, we found that krüppel-like factor 15 (KLF15) repressed the expression of the major RFP detoxification enzyme Cyp3a11 in mice via both direct and indirect mechanisms. Knockout of hepatocyte KLF15 induced the expression of Cyp3a11 and robustly attenuated the hepatotoxicity of RFP in mice. In contrast, overexpression of hepatic KLF15 exacerbated RFP-induced liver injury as well as mortality. More importantly, the suppression of hepatic KLF15 expression strikingly restored liver functions in mice even after being pre-treated with overdosed RFP. Therefore, this study identified the KLF15-Cyp3a11 axis as a novel regulatory pathway that may play an essential role in the detoxification of RFP and associated liver injury. Significance Statement Rifampicin has demonstrated antibacterial effects in the treatment of pulmonary tuberculosis. However, the serious adverse effects on the liver intensively limit the clinical usage of the drug. Permanent depletion and transient inhibition of hepatic KLF15 expression significantly induced the expression of Cyp3a11 and robustly attenuated mouse hepatotoxicity induced by RFP. Overall, our studies show the KLF15-Cyp3a11 axis was identified as a novel regulatory pathway that may play an essential role in the detoxification of RFP and associated liver injury.

Exploring the Potential Consortium of Migraine and Periodontitis.

Various researches have shown periodontitis to share common pathophysiological pathways with systemic diseases such as diabetes, cardiovascular diseases, and osteoporosis and recently neurological disorders. This article provides a narrative review summarizing the various linking mechanisms and the nature of association between two multifactorial diseases-periodontitis and migraine. A literature search was performed for articles related to periodontitis and migraine up till the year 2023 which yielded totally 14 articles. There were only three randomized controlled clinical trials; therefore, we were unable to conduct a systematic review and focused on a narrative review. The keywords searched were "migraine", "periodontitis" and "biomarkers" in PubMed/Medline, Web of Science, and Embase databases. Any article related to the association of periodontitis and migraine and the dental management of subjects with headache disorders were included and studies with migraine and other dental diseases were excluded. It is found that the occurrence of periodontitis and migraine are associated with each other. There is reasonable evidence to believe that periodontitis and migraine are linked by direct and indirect mechanisms which can eventually lead to chronic inflammatory conditions like periodontitis worsening neurovascular conditions such as migraine. However, upon detailed analysis it was found that the strength of association is weak owing to the presences of various common confounding and risk factors. The association between periodontitis and migraine cannot be denied, however, not all the criteria are fulfilled while examining the nature of association and future long-term studies are required to prove the same. Clinical Relevance. Various studies have reported poor periodontal health in patients with migraine. The risk of exacerbation of migraine also increases in subject undergoing dental therapy if the triggering factors are manipulated. Hence, knowing the precise pathophysiologic mechanisms linking both the diseases would be favorable in planning treatment protocols for subjects with migraine.

Interactions Between HDL and CD4+ T Cells: A Novel Understanding of HDL Anti-Inflammatory Properties.

Several studies in animal models and human cohorts have recently suggested that HDLs (high-density lipoproteins) not only modulate innate immune responses but also adaptative immune responses, particularly CD4+ T cells. CD4+ T cells are central effectors and regulators of the adaptive immune system, and any alterations in their homeostasis contribute to the pathogenesis of cardiovascular diseases, autoimmunity, and inflammatory diseases. In this review, we focus on how HDLs and their components affect CD4+ T-cell homeostasis by modulating cholesterol efflux, immune synapsis, proliferation, differentiation, oxidative stress, and apoptosis. While the effects of apoB-containing lipoproteins on T cells have been relatively well established, this review focuses specifically on new connections between HDL and CD4+ T cells. We present a model where HDL may modulate T cells through both direct and indirect mechanisms.

Human Papillomavirus-Associated Giant Clear Cell Acanthoma and Squamous Cell Carcinoma: A Rare Case Report and Literature Review.

Clear cell acanthoma (CCA) and squamous cell carcinoma (SCC) represent distinct entities within dermatological oncology, each posing unique diagnostic and therapeutic challenges. CCA is a rare, benign epidermal growth, often not associated with human papillomavirus (HPV) infection, whereas SCC, a more aggressive form of skin cancer, has been linked to both ultraviolet (UV) exposure and HPV. Understanding the co-occurrence of these conditions in a single patient can enhance diagnostic accuracy and therapeutic outcomes. We report a 64-year-old male who underwent an operation for a verruciform lesion in the right groin, which was diagnosed as HPV-positive CCA alongside keratinised SCC. A literature search across January 2024 revealed limited evidence directly linking HPV to CCA, suggesting a need for further investigation. The speculative association between HPV and CCA warrants deeper exploration, especially considering the potential for HPV to contribute to lesion development through indirect mechanisms. The coexistence of CCA and SCC in an elderly patient presents a unique clinical scenario. This emphasises the need for vigilant diagnosis and tailored treatment strategies, highlighting the gap in understanding the pathogenesis of CCA, particularly its potential association with HPV. Further research is crucial for elucidating the complex interactions governing these conditions and for developing targeted interventions.

Housing and health for people from refugee and asylum-seeking backgrounds: findings from an Australian qualitative longitudinal study

BackgroundFor people from asylum-seeking and refugee backgrounds, housing and the re-establishment of home are key social determinants of health. Research highlights the inequities faced by asylum seekers and refugees in the housing markets of high-income resettlement countries, resulting in their overrepresentation in precarious housing. There is also emerging evidence of the relationship between housing and health for this population relating to lack of affordability, insecurity of tenure, and poor suitability (physical and social). The mechanisms by which housing impacts health for this group within these housing contexts, is however, understudied - especially overtime. This qualitative longitudinal study aimed to address this gap.MethodsSemi-structured interviews were conducted with 25 people from asylum-seeking and refugee backgrounds in South Australia, recruited through a community survey. Thematic analysis of interview data across three time points over three years identified four material and psychosocial mechanisms through which housing contributed to health outcomes via psychological and physical stressors - physical environment; stability; safety; and social connections, support and services. The study also identified additional health promoting resources, particularly elements of ontological security. The dynamics of these indirect and direct mechanisms were further illuminated by considering the impact of international, national and local contexts and a range of intersecting social factors including gender, country/culture of origin, family circumstances, immigration status, language skills, income, and health status.ConclusionsRebuilding a sense of home and ontological security is a key resettlement priority and crucial for wellbeing. More comprehensive strategies to facilitate this for refugees and asylum seekers are required.

The Role of Hepatitis Viruses as Drivers of Hepatocancerogenesis.

Recently, metabolic associated steatotic liver disease (MASLD) became the leading cause of chronic liver disease worldwide and one of the most frequent causes of hepatocellular carcinoma (HCC). Nonetheless, in this epidemiological trend, viral hepatitis remains the major driver in hepatic carcinogenesis. Globally, hepatitis B virus (HBV) is the leading cause of hepatocellular carcinoma, with an overall attributable risk of approximately 40%, followed by hepatitis C virus (HCV), which accounts for 28-30% of cases, with significant geographic variations between the Eastern and Western world. Considering all the etiologies, HCC risk increases proportionally with the progression of liver disease, but the risk is consistently higher in patients with viral triggers. This evidence indicates that both direct (due to the oncogenic properties of the viruses) and indirect (through the mechanisms of chronic inflammation that lead to cirrhosis) mechanisms are involved, alongside the presence of co-factors contributing to liver damage (smoking, alcohol, and metabolic factors) that synergistically enhance the oncogenic process. The aim of this review is to analyze the oncogenic role of hepatitis viruses in the liver, evaluating epidemiological changes and direct and indirect viral mechanisms that lead to liver cancer.

Adaptive promising zone design for cancer immunotherapy with heterogeneous delayed treatment effect

ABSTRACT Indirect mechanisms of cancer immunotherapies result in delayed treatment effects that vary among patients. Consequently, the use of the log-rank test in trial design and analysis can lead to significant power loss and pose additional challenges for interim decisions in adaptive designs. In this paper, we describe patients’ survival using a piecewise proportional hazard model with random lag time and propose an adaptive promising zone design for cancer immunotherapy with heterogeneous delayed effects. We provide solutions for calculating conditional power and adjusting the critical value for the log-rank test with interim data. We divide the sample space into three zones – unfavourable, promising, and favourable –based on re-estimations of the survival parameters, the log-rank test statistic at the interim analysis, and the initial and maximum sample sizes. If the interim results fall into the promising zone, the sample size is increased; otherwise, it remains unchanged. We show through simulations that our proposed approach has greater overall power than the fixed sample design and similar power to the matched group sequential trial. Furthermore, we confirm that critical value adjustment effectively controls the type I error rate inflation. Finally, we provide recommendations on the implementation of our proposed method in cancer immunotherapy trials.

Unveiling the Biocontrol Potential of Rhizoplane Bacillus Species against Sugarcane Fusarium Wilt through Biochemical and Molecular Analysis.

Biocontrol is regarded as a viable alternate technique for managing sugarcane wilt disease caused by Fusarium sacchari. Many fungal antagonists against F. sacchari, have been reported, but the potential of bacterial antagonists was explored to a limited extent, so the present study evaluated the antagonistic potential of rhizoplane Bacillus species and their mode of action. A total of twenty Bacillus isolates from the rhizoplane of commercially grown sugarcane varieties were isolated. The potential isolate SRB2 had shown inhibition of 52.30, 33.33, & 44.44% and SRB20 of 35.00, 33.15, & 36.85% in direct, indirect, and remote confrontation respectively against F. sacchari. The effective strains were identified as Bacillus inaquosorum strain SRB2 and B. vallismortis strain SRB20, by PCR amplification of 16S-23S intergenic region. The biochemical studies on various direct and indirect biocontrol mechanisms revealed the production of IAA, Protease, Cellulase, Siderophores, and P solubilization. The molecular analysis revealed the presence of antimicrobial peptides biosynthetic genes like fenD (Fengycin), bmyB (Bacyllomicin) ituC (Iturin) and spaS (Subtilin) which provided a competitive edge to these isolates compared to other Bacillus strains. Under greenhouse experiments, the sett bacterization with SRB2, significantly (P < 0.001) reduced the seedling mortality by > 70% followed by SRB20 in F. sacchari inoculated pots. The study revealed that the isolates B. inaquosorum SRB2 and B. vallismortis SRB20 can be used as potential bioagents against sugarcane Fusarium wilt.

A Lacticaseibacillus rhamnosus secretome induces immunoregulatory transcriptional, functional and immunometabolic signatures in human THP-1 monocytes

Macrophage responses to activation are fluid and dynamic in their ability to respond appropriately to challenges, a role integral to host defence. While bacteria can influence macrophage differentiation and polarization into pro-inflammatory and alternatively activated phenotypes through direct interactions, many questions surround indirect communication mechanisms mediated through secretomes derived from gut bacteria, such as lactobacilli. We examined effects of secretome-mediated conditioning on THP-1 human monocytes, focusing on the ability of the Lacticaseibacillus rhamnosus R0011 secretome (LrS) to drive macrophage differentiation and polarization and prime immune responses to subsequent challenge with lipopolysaccharide (LPS). Genome-wide transcriptional profiling revealed increased M2-associated gene transcription in response to LrS conditioning in THP-1 cells. Cytokine and chemokine profiling confirmed these results, indicating increased M2-associated chemokine and cytokine production (IL-1Ra, IL-10). These cells had increased cell-surface marker expression of CD11b, CD86, and CX3CR1, coupled with reduced expression of the M1 macrophage-associated marker CD64. Mitochondrial substrate utilization assays indicated diminished reliance on glycolytic substrates, coupled with increased utilization of citric acid cycle intermediates, characteristics of functional M2 activity. LPS challenge of LrS-conditioned THP-1s revealed heightened responsiveness, indicative of innate immune priming. Resting stage THP-1 macrophages co-conditioned with LrS and retinoic acid also displayed an immunoregulatory phenotype with expression of CD83, CD11c and CD103 and production of regulatory cytokines. Secretome-mediated conditioning of macrophages into an immunoregulatory phenotype is an uncharacterized and potentially important route through which lactic acid bacteria and the gut microbiota may train and shape innate immunity at the gut-mucosal interface.

Abstract LB121: Endothelial cells mediated paracrine signaling alters immune cell modulators on colorectal cancer cells

Abstract Background: Metastatic colorectal cancer (mCRC) is the second leading cause of cancer related deaths in the US. Various factors in the tumor microenvironment (TME) play significant roles in progression of CRC tumors and their response to various therapies. Previous studies from our laboratory and other groups have demonstrated that blood vessels and their constituent endothelial cells (ECs) exert strong effects on CRC cells by altering stemness, enhancing drug resistance, and increasing cell survival. Although ECs have also been shown to affect immune cell function or alter the tumor immune environment by direct or indirect mechanisms, their role in altering immune-modulating effectors on tumor cells, especially CRC cells, are poorly understood. Thus, elucidating the role of ECs in regulating immune-modulators in CRC cells and understanding the underlying mechanisms by which this occurs will provide important insights into the role of ECs on altering the immune-microenvironment of CRC tumors that likely affects tumor progression and, possibly, response to immunotherapies. Methods: A panel of CRC cells lines were exposed to conditioned media (CM) from CRC or multiple primary or immortalized liver parenchymal endothelial cells (LPECs), and alterations in some of the known immune-inhibitory ligands were measured by western blotting or flow cytometry. Molecular size-based fractionation of CRC-CM or LPEC-CM were performed and various sized fractions were utilized to detect fractions harboring inducers of immune-inhibitory ligands. Mass spectrometry was performed to identify possible factors in LPEC-CM. Western blotting of CRC cell lysates was performed to identify possible signaling changes following LPEC-CM treatment. Results: Our studies demonstrated that ECs were more efficient in inducing PD-L1 expression in CRC cells compared to other cell types present in the CRC tumor microenvironment. LPEC-CM induced PD-L1 expression in multiple CRC cells regardless of their genetic mutations or MSI-H/MSS status. Initial studies indicate that LPEC-CM can also enhance MHC-1 expression in CRC cells. Size-fractionation studies indicate that inducer/s of PD-L1 expression are present in a fraction &amp;gt;100kDa. Mass-spectrometry of this fraction has identified prospective candidates that can possibly induce PD-L1 on CRC cells. CRC cells treated with LPEC-CM led to enhanced levels of pSTAT3, a known PD-L1 transcription factor. Conclusions: Our studies, for the first time, demonstrate that ECs, through paracrine signaling, can educate CRC cells to overexpress immune-modulatory ligands. Further studies are being conducted to elucidate the molecular factors involved in these processes. These studies not only shed light on the complex role played by ECs in modulating the TME, but also warrants further investigations into the effects of these changes in CRC tumor progression and responses to therapies. Citation Format: FanFan, Lee M. Ellis, Rajat Bhattacharya. Endothelial cells mediated paracrine signaling alters immune cell modulators on colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB121.

Hypoxia leads to diminished ovarian reserve in an age dependent manner.

Perinatal hypoxia causes premature activation and initiation of growth in dormant follicles, leading to diminished ovarian reserve. An indirect mechanism such as the release of stress-related hormones, may influence ovarian follicle recruitment under hypoxic conditions. We wanted to determine whether hypoxic ovarian damage results from increased follicle growth and "burnout" or from increased apoptosis, and whether this damage is age-dependent. Animal study Participants/Materials, Setting, Methods: Using adult 6-week-old (n=8) and one-day-old newborn (n=20) ICR (CD-1) female mice, ovarian follicular counts were conducted on H&E-stained sections. Immunohistochemistry was performed on sections stained with Ki-67, anti-Caspase 3 and anti-FOXO3A. Exposure to hypoxia resulted in significantly reduced proportion of primordial follicles vs normoxia in both adult dams and newborn pups (3.17±2.75% vs. 17.89±4.4%; p=0.004; 40.59±14.88% vs. 81.92±31.56%, p=0.001, respectively), concomitant with increased growing- primary and secondary follicles, and more pronounced in adult dams vs newborn pups (6-fold vs. 2-fold, respectively). Ki67 staining revealed higher scores of cell proliferation in follicular granulosa cells after exposure to hypoxia than normoxia. However, Caspase 3 and Foxo3A staining did not show any differences in these markers of apoptosis in oocytes, granulosa cells, theca cells, or stromal cells when exposed to hypoxia versus normoxia. The current study has several limitations; first, the sample size for each group is relatively small, which could limit the generalizability of the findings. Second, the study uses an ex vivo culture system, which may not fully capture the complex interactions that occur in the whole animal. Third, the exposure to hypoxia only lasted for 3 hours, which may not be long enough to observe all the potential effects. In addition, the study only analyzed specific markers of apoptosis in a few cell types, and other cell types or apoptotic pathways might be involved. Lastly, the study provides evidence for accelerated follicular activation and decreased ovarian reserve, but the underlying mechanisms are not fully explored. Conclusions Direct tissue hypoxia led to premature activation and initiation of growth in dormant follicles leading to diminished ovarian reserve. Hypoxic damage is age-dependent, with adult ovaries more susceptible than newborn ovaries. These findings support the possibility of follicular "burn out" as a potential mechanism responsible for hypoxia-induced loss of ovarian reserve.