Pirfenidone Alleviates Inflammation and Fibrosis of Acute Respiratory Distress Syndrome by Modulating the Transforming Growth Factor-ß/Smad Signaling Pathway.

Acute respiratory distress syndrome (ARDS) occurs as an acute onset condition, and patients present with diffuse alveolar damage, refractory hypoxemia, and non-cardiac pulmonary edema. ARDS progresses through an initial exudative phase, an inflammatory phase, and a final fibrotic phase. Pirfenidone, a powerful anti-fibrotic agent, is known as an agent that inhibits the progression of fibrosis in idiopathic pulmonary fibrosis. In this study, we studied the treatment efficiency of pirfenidone on lipopolysaccharide (LPS) and bleomycin-induced ARDS using rats. The ARDS rat model was created by the intratracheal administration of 3 mg/kg LPS of and 3 mg/kg of bleomycin dissolved in 0.2 mL of normal saline. The pirfenidone treatment group was administered 100 or 200 mg/kg of pirfenidone dissolved in 0.5 mL distilled water orally 10 times every 2 days for 20 days. The administration of LPS and bleomycin intratracheally increased lung injury scores and significantly produced pro-inflammatory cytokines. ARDS induction increased the expressions of transforming growth factor (TGF)-ß1/Smad-2 signaling factors. Additionally, matrix metalloproteinase (MMP)-9/tissue inhibitor of metalloproteinase (TIMP)-1 imbalance occurred, resulting in enhanced fibrosis-related factors. Treatment with pirfenidone strongly suppressed the expressions of TGF-ß1/Smad-2 signaling factors and improved the imbalance of MMP-9/TIMP-1 compared to the untreated group. These effects led to a decrease in fibrosis factors and pro-inflammatory cytokines, promoting the recovery of damaged lung tissue. These results of this study showed that pirfenidone administration suppressed inflammation and fibrosis in the ARDS animal model. Therefore, pirfenidone can be considered a new early treatment for ARDS.

Nurse's, physician's and family member's experiences of withholding or withdrawing life-sustaining treatment process in an intensive care unit.

AIMS: To explore nurse's, physician's and family member's experiences of withholding or withdrawing life-sustaining treatment in an intensive care unit. BACKGROUND: In South Korea, withholding or withdrawing life-sustaining treatment is legalised by the enforcement of the Hospice, Palliative Care and Life-sustaining Treatment Decision-making Act (2018). The Act (2018) is the first legal ground for making decisions regarding life-sustaining treatment in South Korea. DESIGN: Focused ethnography. The standards for reporting qualitative research checklist is used. METHODS: Interview data are collected between August 2018 and January 2019 using semi-structured interviews with 23 nurses, 10 physicians and four family members in a South Korean intensive care unit. The interview data are analysed following the thematic analysis of Braun and Clarke. RESULTS: An overarching theme of 'constructing death' is identified from the experiences of nurses, physicians and family members regarding withholding or withdrawing life-sustaining treatment in a South Korean intensive care unit. Family members had the strongest power in the withholding or withdrawing life-sustaining treatment process whilst the process had to be based on medical consideration. All the research participants shared the purpose and motivation of withholding or withdrawing life-sustaining treatment as the dying patient's dignity. Due to the South Korean national health insurance system, the relationships between medical staff and family members were driven by customer ideology. CONCLUSION: The impact and linkage of the context of familism culture and health insurance with the process of withholding or withdrawing life-sustaining treatment in South Korea are shown in this research. The findings of this research inspire future studies to uncover the impact of the cultural context in the decision-making process of a patient's death, to explore the dynamics of family members under cultural values and to explore the influence of the healthcare system and medical costs on the relationships between medical staff and family members. RELEVANCE TO CLINICAL PRACTICE: By integrating the experiences of nurses, physicians and family members, the findings of this study inform the shared values in the context of familism culture and the health insurance system. In particular, understanding family dynamics when a patient's dying and death as a result of withholding or withdrawing life-sustaining treatment informs nurses to provide quality of care in the intensive care setting. Therefore, the findings of this research contribute to distinguishing the priority in care when withholding or withdrawing life-sustaining treatment, rapidly changing the aims of care from the patient's recovery to a dignified death.

AIM2 inflammasome mediates hallmark neuropathological alterations and cognitive impairment in a mouse model of vascular dementia.

Chronic cerebral hypoperfusion is associated with vascular dementia (VaD). Cerebral hypoperfusion may initiate complex molecular and cellular inflammatory pathways that contribute to long-term cognitive impairment and memory loss. Here we used a bilateral common carotid artery stenosis (BCAS) mouse model of VaD to investigate its effect on the innate immune response-particularly the inflammasome signaling pathway. Comprehensive analyses revealed that chronic cerebral hypoperfusion induces a complex temporal expression and activation of inflammasome components and their downstream products (IL-1ß and IL-18) in different brain regions, and promotes activation of apoptotic and pyroptotic cell death pathways. Polarized glial-cell activation, white-matter lesion formation and hippocampal neuronal loss also occurred in a spatiotemporal manner. Moreover, in AIM2 knockout mice we observed attenuated inflammasome-mediated production of proinflammatory cytokines, apoptosis, and pyroptosis, as well as resistance to chronic microglial activation, myelin breakdown, hippocampal neuronal loss, and behavioral and cognitive deficits following BCAS. Hence, we have demonstrated that activation of the AIM2 inflammasome substantially contributes to the pathophysiology of chronic cerebral hypoperfusion-induced brain injury and may therefore represent a promising therapeutic target for attenuating cognitive impairment in VaD.

Autoencoder-Based Target Detection in Automotive MIMO FMCW Radar System.

In general, a constant false alarm rate algorithm (CFAR) is widely used to automatically detect targets in an automotive frequency-modulated continuous wave (FMCW) radar system. However, if the number of guard cells, the number of training cells, and the probability of false alarm are set improperly in the conventional CFAR algorithm, the target detection performance is severely degraded. Therefore, we propose a method using a convolutional neural network-based autoencoder (AE) to replace the CFAR algorithm in the multiple-input and multiple-output FMCW radar system. In the AE, the entire detection result is compressed at the encoder side, and only significant signal components are recovered on the decoder side. In this work, by changing the number of hidden layers and the number of filters in each layer, the structure of the AE showing a high signal-to-noise ratio in the target detection result is determined. To evaluate the performance of the proposed method, the AE-based target detection result is compared with the target detection results of conventional CFAR algorithms. As a result of calculating the correlation coefficient with the data marked with the actual target position, the proposed AE-based target detection shows the highest similarity with a correlation of 0.73 or higher.

Identification of Multiple Hub Genes in Acute Kidney Injury after Kidney Transplantation by Bioinformatics Analysis.

Background and Objectives: The molecular mechanisms of the development of acute kidney injury (AKI) after kidney transplantation are not yet clear. The aim of this study was to confirm the genes and mechanisms related to AKI after transplantation. Materials and Methods: To investigate potential genetic targets for AKI, an analysis of the gene expression omnibus database was used to identify key genes and pathways. After identification of differentially expressed genes, Kyoto Encyclopedia of Genes and Genome pathway enrichment analyses were performed. We identified the hub genes and established the protein-protein interaction network. Results: Finally, we identified 137 differentially expressed genes (59 upregulated genes and 16 downregulated genes). AKAP12, AMOT, C3AR1, LY96, PIK3AP1, PLCD4, PLCG2, TENM2, TLR2, and TSPAN5 were filtrated by the hub genes related to the development of post-transplant AKI from the Protein-Protein Interaction (PPI) network. Conclusions: This may provide important evidence of the diagnostic and therapeutic biomarker of AKI.

Developing a Loop-Mediated Isothermal Amplification Assay for the Rapid Detection of Seven Respiratory Viruses including SARS-CoV-2.

Background and Objectives: The coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to be a pandemic even in 2022. As the initial symptoms of COVID-19 overlap with those of infections from other respiratory viruses, an accurate and rapid diagnosis of COVID-19 is essential for administering appropriate treatment to patients. Currently, the most widely used method for detecting respiratory viruses is based on real-time polymerase chain reaction (PCR) and includes reverse-transcription real-time quantitative PCR (RT-qPCR). However, RT-qPCR assays require sophisticated facilities and are time-consuming. This study aimed to develop a real-time quantitative loop-mediated isothermal amplification (RT-qLAMP) assay and compare its analytical performance with RT-qPCR. Materials and Methods: A total of 315 nasopharyngeal swabs from patients with symptoms of respiratory infections were included in this study. A primary screening of the specimens was performed using RT-qPCR. RNA/DNA from standard strains for respiratory viruses and heat-inactivated preparations of standard strains for SARS-CoV-2 were used to evaluate the accuracy and target specificity of the RT-qLAMP assay. Results: We successfully developed an RT-qLAMP assay for seven respiratory viruses: respiratory syncytial virus (RSV) A, RSV B, adenovirus, influenza (Flu) A (H1N1 and H3N2), Flu B, and SARS-CoV-2. RT-qLAMP was performed in a final reaction volume of 9.6 µL. No cross-reactivity was observed. Compared with the RT-PCR results, the sensitivity and specificity of the RT-qLAMP assay were 95.1% and 100%, respectively. The agreement between the two methods was 97.1%. The median amplification time to RT-qLAMP positivity was 22:34 min (range: 6:80-47:98 min). Conclusions: The RT-qLAMP assay requires a small number of reagents and samples and is performed with an isothermal reaction. This study established a fast, simple, and sensitive test that can be applied to point-of-care testing devices to facilitate the detection of respiratory viruses, including SARS-CoV-2.

Identification of Human Motion Using Radar Sensor in an Indoor Environment.

In this paper, we propose a method of identifying human motions, such as standing, walking, running, and crawling, using a millimeter wave radar sensor. In our method, two signal processing is performed in parallel to identify the human motions. First, the moment at which a person's motion changes is determined based on the statistical characteristics of the radar signal. Second, a deep learning-based classification algorithm is applied to determine what actions a person is taking. In each of the two signal processing, radar spectrograms containing the characteristics of the distance change over time are used as input. Finally, we evaluate the performance of the proposed method with radar sensor data acquired in an indoor environment. The proposed method can find the moment when the motion changes with an error rate of 3%, and also can classify the action that a person is taking with more than 95% accuracy.

Transcriptome analysis reveals intermittent fasting-induced genetic changes in ischemic stroke.

Genetic changes due to dietary intervention in the form of either calorie restriction (CR) or intermittent fasting (IF) are not reported in detail until now. However, it is well established that both CR and IF extend the lifespan and protect against neurodegenerative diseases and stroke. The current research aims were first to describe the transcriptomic changes in brains of IF mice and, second, to determine whether IF induces extensive transcriptomic changes following ischemic stroke to protect the brain from injury. Mice were randomly assigned to ad libitum feeding (AL), 12 (IF12) or 16 (IF16) h daily fasting. Each diet group was then subjected to sham surgery or middle cerebral artery occlusion and consecutive reperfusion. Mid-coronal sections of ipsilateral cerebral tissue were harvested at the end of the 1 h ischemic period or at 3, 12, 24 or 72 h of reperfusion, and genome-wide mRNA expression was quantified by RNA sequencing. The cerebral transcriptome of mice in AL group exhibited robust, sustained up-regulation of detrimental genetic pathways under ischemic stroke, but activation of these pathways was suppressed in IF16 group. Interestingly, the cerebral transcriptome of AL mice was largely unchanged during the 1 h of ischemia, whereas mice in IF16 group exhibited extensive up-regulation of genetic pathways involved in neuroplasticity and down-regulation of protein synthesis. Our data provide a genetic molecular framework for understanding how IF protects brain cells against damage caused by ischemic stroke, and reveal cellular signaling and bioenergetic pathways to target in the development of clinical interventions.

Effect of sugammadex on chest radiographic abnormality in the early postoperative period after video-assisted thoracoscopic lobectomy

Background/aim: Sugammadex, which offsets the effects of neuromuscular blocking agents (NMBs), has advantages over traditional reversal agents like pyridostigmine, as it enables fast and reliable recovery from neuromuscular blockade. This study compared the incidence of early postoperative chest radiographic abnormalities (CRA) between sugammadex (group S) and pyridostigmine (group P) following video-assisted thoracoscopic (VAT) lobectomy for lung cancer. Materials and methods: We performed a retrospective cohort analysis by reviewing the medical records of patients who underwent VAT lobectomy at a single university medical center. We defined the early postoperative CRA as a characteristic appearance on chest radiograph up to 2 days after surgery. Arterial blood gas analysis (ABGA), surgical time, anaesthesia time, extubation time, and the total dose of rocuronium were analysed. Postoperative nausea and vomiting (PONV) and pain scores were observed until 2 days after surgery. Results: A total of 257 patients underwent VAT lobectomy during the study period; 159 were included in the final analysis. Ninety patients received sugammadex while 69 received pyridostigmine. The incidence of early postoperative atelectasis was significantly lower in group S than in group P (26.7%, 95% CI: 17.5%‒35.8% and 43.5%, 95% CI: 31.8%‒55.2%, respectively, P = 0.013). The median dose of rocuronium was higher in group S than in group P (120 mg vs. 90 mg, P < 0.001). ABGA, extubation time, and PONV were similar in both groups. Conclusion: Sugammadex decreased the incidence of CRA in the early postoperative period despite higher NMB consumption.

Evidence that NLRC4 inflammasome mediates apoptotic and pyroptotic microglial death following ischemic stroke.

Stroke is the second leading cause of death in the world and a major cause of long-term disability. Recent evidence has provided insight into a newly described inflammatory mechanism that contributes to neuronal and glial cell death, and impaired neurological outcome following ischemic stroke - a form of sterile inflammation involving innate immune complexes termed inflammasomes. It has been established that inflammasome activation following ischemic stroke contributes to neuronal cell death, but little is known about inflammasome function and cell death in activated microglial cells following cerebral ischemia. Microglia are considered the resident immune cells that function as the primary immune defense in the brain. This study has comprehensively investigated the expression and activation of NLRP1, NLRP3, NLRC4 and AIM2 inflammasomes in isolates of microglial cells subjected to simulated ischemic conditions and in the brain following ischemic stroke. Immunoblot analysis from culture media indicated microglial cells release inflammasome components and inflammasome activation-dependent pro-inflammatory cytokines following ischemic conditions. In addition, a functional role for NLRC4 inflammasomes was determined using siRNA knockdown of NLRC4 and pharmacological inhibitors of caspase-1 and -8 to target apoptotic and pyroptotic cell death in BV2 microglial cells under ischemic conditions. In summary, the present study provides evidence that the NLRC4 inflammasome complex mediates the inflammatory response, as well as apoptotic and pyroptotic cell death in microglial cells under in vitro and in vivo ischemic conditions.

Cerebral transcriptome analysis reveals age-dependent progression of neuroinflammation in P301S mutant tau transgenic male mice.

Aggregation of the microtubule-associated protein, tau, can lead to neurofibrillary tangle formation in neurons and glia which is the hallmark of tauopathy. The cellular damage induced by the formation of neurofibrillary tangles leads to neuroinflammation and consecutive neuronal death. However, detailed observation of transcriptomic changes under tauopathy together with the comparison of age-dependent progression of neuroinflammatory gene expressions mediated by tau overexpression is required. Employing RNA sequencing on PS19 transgenic mice that overexpress human mutant tau harboring the P301S mutation, we have examined the effects of age-dependent tau overexpression on transcriptomic changes of immune and inflammatory responses in the cerebral cortex. Compared to age-matched wild type control, P301S transgenic mice exhibit significant transcriptomic alterations. We have observed age-dependent neuroinflammatory gene expression changes in both wild type and P301S transgenic mice where tau overexpression further promoted the expression of neuroinflammatory genes in 10-month old P301S transgenic mice. Moreover, functional gene network analyses (gene ontology and pathway enrichment) and prospective target protein interactions predicted the potential involvement of multiple immune and inflammatory pathways that may contribute to tau-mediated neuronal pathology. Our current study on P301S transgenic mice model revealed for the first time, the differences of gene expression patterns in both early and late stage of tau pathology in cerebral cortex. Our analyses also revealed that tau overexpression alone induces multiple inflammatory and immune transcriptomic changes and may provide a roadmap to elucidate the targets of anti-inflammatory therapeutic strategy focused on tau pathology and related neurodegenerative diseases.

Structural insights into the molecular mechanism of Escherichia coli SdiA, a quorum-sensing receptor.

Escherichia coli SdiA is a quorum-sensing (QS) receptor that responds to autoinducers produced by other bacterial species to control cell division and virulence. Crystal structures reveal that E. coli SdiA, which is composed of an N-terminal ligand-binding domain and a C-terminal DNA-binding domain (DBD), forms a symmetrical dimer. Although each domain shows structural similarity to other QS receptors, SdiA differs from them in the relative orientation of the two domains, suggesting that its ligand-binding and DNA-binding functions are independent. Consistently, in DNA gel-shift assays the binding affinity of SdiA for the ftsQP2 promoter appeared to be insensitive to the presence of autoinducers. These results suggest that autoinducers increase the functionality of SdiA by enhancing the protein stability rather than by directly affecting the DNA-binding affinity. Structural analyses of the ligand-binding pocket showed that SdiA cannot accommodate ligands with long acyl chains, which was corroborated by isothermal titration calorimetry and thermal stability analyses. The formation of an intersubunit disulfide bond that might be relevant to modulation of the DNA-binding activity was predicted from the proximal position of two Cys residues in the DBDs of dimeric SdiA. It was confirmed that the binding affinity of SdiA for the uvrY promoter was reduced under oxidizing conditions, which suggested the possibility of regulation of SdiA by multiple independent signals such as quorum-sensing inducers and the oxidation state of the cell.

Structural and functional characterization of an Isd-type haem-degradation enzyme from Listeria monocytogenes.

Bacterial pathogens have evolved diverse types of efficient machinery to acquire haem, the most abundant source of iron in the human body, and degrade it for the utilization of iron. Gram-positive bacteria commonly encode IsdG-family proteins as haem-degrading monooxygenases. Listeria monocytogenes is predicted to possess an IsdG-type protein (Lmo2213), but the residues involved in haem monooxygenase activity are not well conserved and there is an extra N-terminal domain in Lmo2213. Therefore, its function and mechanism of action cannot be predicted. In this study, the crystal structure of Lmo2213 was determined at 1.75 Šresolution and its haem-binding and haem-degradation activities were confirmed. Structure-based mutational and functional assays of this protein, designated as an Isd-type L. monocytogenes haem-degrading enzyme (Isd-LmHde), identified that Glu71, Tyr87 and Trp129 play important roles in haem degradation and that the N-terminal domain is also critical for its haem-degrading activity. The haem-degradation product of Isd-LmHde is verified to be biliverdin, which is also known to be the degradation product of other bacterial haem oxygenases. This study, the first structural and functional report of the haem-degradation system in L. monocytogenes, sheds light on the concealed haem-utilization system in this life-threatening human pathogen.

Solution structure of the Zbeta domain of human DNA-dependent activator of IFN-regulatory factors and its binding modes to B- and Z-DNAs.

The DNA-dependent activator of IFN-regulatory factors (DAI), also known as DLM-1/ZBP1, initiates an innate immune response by binding to foreign DNAs in the cytosol. For full activation of the immune response, three DNA binding domains at the N terminus are required: two Z-DNA binding domains (ZBDs), Zα and Zß, and an adjacent putative B-DNA binding domain. The crystal structure of the Zß domain of human DAI (hZß(DAI)) in complex with Z-DNA revealed structural features distinct from other known Z-DNA binding proteins, and it was classified as a group II ZBD. To gain structural insights into the DNA binding mechanism of hZß(DAI), the solution structure of the free hZß(DAI) was solved, and its bindings to B- and Z-DNAs were analyzed by NMR spectroscopy. Compared to the Z-DNA-bound structure, the conformation of free hZß(DAI) has notable alterations in the α3 recognition helix, the "wing," and Y145, which are critical in Z-DNA recognition. Unlike some other Zα domains, hZß(DAI) appears to have conformational flexibility, and structural adaptation is required for Z-DNA binding. Chemical-shift perturbation experiments revealed that hZß(DAI) also binds weakly to B-DNA via a different binding mode. The C-terminal domain of DAI is reported to undergo a conformational change on B-DNA binding; thus, it is possible that these changes are correlated. During the innate immune response, hZß(DAI) is likely to play an active role in binding to DNAs in both B and Z conformations in the recognition of foreign DNAs.

IF1 Promotes Cellular Proliferation and Inhibits Oxidative Phosphorylation in Mouse Embryonic Fibroblasts under Normoxia and Hypoxia.

ATP synthase inhibitory factor subunit 1 (IF1) is an inhibitory subunit of mitochondrial ATP synthase, playing a crucial role in regulating mitochondrial respiration and energetics. It is well-established that IF1 interacts with the F1 sector of ATP synthase to inhibit the reversal rotation and, thus, ATP hydrolysis. Recent evidence supports that IF1 also inhibits forward rotation or the ATP synthesis activity. Adding to the complexity, IF1 may also facilitate mitophagy and cristae formation. The implications of these complex actions of IF1 for cellular function remain obscure. In the present study, we found that IF1 expression was markedly upregulated in hypoxic MEFs relative to normoxic MEFs. We investigate how IF1 affects cellular growth and function in cultured mouse embryonic fibroblasts derived from mouse lines with systemic IF1 overexpression and knockout under normoxia and hypoxia. Cell survival and proliferation analyses revealed that IF1 overexpression exerted limited effects on cellular viability but substantially increased proliferation under normoxia, whereas it facilitated both cellular viability and proliferation under hypoxia. The absence of IF1 may have a pro-survival effect but not a proliferative one in both normoxia and hypoxia. Cellular bioenergetic analyses revealed that IF1 suppressed cellular respiration when subjected to normoxia and was even more pronounced when subjected to hypoxia with increased mitochondrial ATP production. In contrast, IF1 knockout MEFs showed markedly increased cellular respiration under both normoxia and hypoxia with little change in mitochondrial ATP. Glycolytic stress assay revealed that IF1 overexpression modestly increased glycolysis in normoxia and hypoxia. Interestingly, the absence of IF1 in MEFs led to substantial increases in glycolysis. Therefore, we conclude that IF1 mainly inhibits cellular respiration and enhances cellular glycolysis to preserve mitochondrial ATP. On the other hand, IF1 deletion can significantly facilitate cellular respiration and glycolysis without leading to mitochondrial ATP deficit.

Sphingosine-1-Phosphate Inhibition Increases Endoplasmic Reticulum Stress to Enhance Oxaliplatin Sensitivity in Pancreatic Cancer.

Background: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer resistant to current therapies, including oxaliplatin (Oxa). Growing evidence supports the ability of cancers to harness sphingolipid metabolism for survival. Sphingosine-1-phosphate (S1P) is an anti-apoptotic, pro-survival mediator that can influence cellular functions such as endoplasmic reticulum (ER) stress. We hypothesize that PDAC drives dysregulated sphingolipid metabolism and that S1P inhibition can enhance ER stress to improve therapeutic response to Oxa in PDAC. Methods: RNA sequencing data of sphingolipid mediators from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression Project (GTEx) datasets were analyzed. Murine and human PDAC cell lines were treated with small interfering RNA (siRNA) against sphingosine kinase-2 (SPHK2) or ABC294640 (ABC) and incubated with combinations of vehicle control or Oxa. In an orthotopic syngeneic KPC PDAC model, tumors were treated with either vehicle control, Oxa, ABC, or combination therapy. Results: RNA sequencing analysis revealed multiple significantly differentially expressed sphingolipid mediators (P < 0.05). In vitro, both siRNA knockdown of SPHK2 and ABC sensitized cells to Oxa therapy (P < 0.05), and induced eukaryotic initiation factor 2α (eIF2α) and protein kinase RNA-like endoplasmic reticulum kinase (PERK) phosphorylation, hallmarks of ER stress. In vitro therapy also increased extracellular high mobility group box 1 (HMGB1) release (P < 0.05), necessary for immunogenic cell death (ICD). In vivo combination therapy increased apoptotic markers as well as the intensity of HMGB1 staining compared to control (P < 0.05). Conclusions: Our evidence suggests that sphingolipid metabolism is dysregulated in PDAC. Furthermore, S1P inhibition can sensitize PDAC to Oxa therapy through increasing ER stress and can potentiate ICD induction. This highlights a potential therapeutic target for chemosensitizing PDAC as well as an adjunct for future chemoimmunotherapy strategies.

Translational and oncologic significance of tertiary lymphoid structures in pancreatic adenocarcinoma.

Pancreatic adenocarcinoma (PDAC) is an aggressive tumor with poor survival and limited treatment options. PDAC resistance to immunotherapeutic strategies is multifactorial, but partially owed to an immunosuppressive tumor immune microenvironment (TiME). However, the PDAC TiME is heterogeneous and harbors favorable tumor-infiltrating lymphocyte (TIL) populations. Tertiary lymphoid structures (TLS) are organized aggregates of immune cells that develop within non-lymphoid tissue under chronic inflammation in multiple contexts, including cancers. Our current understanding of their role within the PDAC TiME remains limited; TLS are complex structures with multiple anatomic features such as location, density, and maturity that may impact clinical outcomes such as survival and therapy response in PDAC. Similarly, our understanding of methods to manipulate TLS is an actively developing field of research. TLS may function as anti-tumoral immune niches that can be leveraged as a therapeutic strategy to potentiate both existing chemotherapeutic regimens and potentiate future immune-based therapeutic strategies to improve patient outcomes. This review seeks to cover anatomy, relevant features, immune effects, translational significance, and future directions of understanding TLS within the context of PDAC.

Intratumoral immune triads are required for immunotherapy-mediated elimination of solid tumors.

Tumor-specific CD8+ T cells are frequently dysfunctional and unable to halt tumor growth. We investigated whether tumor-specific CD4+ T cells can be enlisted to overcome CD8+ T cell dysfunction within tumors. We find that the spatial positioning and interactions of CD8+ and CD4+ T cells, but not their numbers, dictate anti-tumor responses in the context of adoptive T cell therapy as well as immune checkpoint blockade (ICB): CD4+ T cells must engage with CD8+ T cells on the same dendritic cell during the effector phase, forming a three-cell-type cluster (triad) to license CD8+ T cell cytotoxicity and cancer cell elimination. When intratumoral triad formation is disrupted, tumors progress despite equal numbers of tumor-specific CD8+ and CD4+ T cells. In patients with pleural mesothelioma treated with ICB, triads are associated with clinical responses. Thus, CD4+ T cells and triads are required for CD8+ T cell cytotoxicity during the effector phase and tumor elimination.

MAGE-A4-Responsive Plasma Cells Promote Non-Small Cell Lung Cancer.

Adaptive immunity is critical to eliminate malignant cells, while multiple tumor-intrinsic factors can alter this protective function. Melanoma antigen-A4 (MAGE-A4), a cancer-testis antigen, is expressed in several solid tumors and correlates with poor survival in non-small cell lung cancer (NSCLC), but its role in altering antitumor immunity remains unclear. We found that expression of MAGE-A4 was highly associated with the loss of PTEN , a tumor suppressor, in human NSCLC. Here we show that constitutive expression of human MAGE-A4 combined with the loss of Pten in mouse airway epithelial cells results in metastatic adenocarcinoma enriched in CD138 + CXCR4 + plasma cells, predominantly expressing IgA. Consistently, human NSCLC expressing MAGE-A4 showed increased CD138 + IgA + plasma cell density surrounding tumors. The abrogation of MAGE-A4-responsive plasma cells (MARPs) decreased tumor burden, increased T cell infiltration and activation, and reduced CD163 + CD206 + macrophages in mouse lungs. These findings suggest MAGE-A4 promotes NSCLC tumorigenesis, in part, through the recruitment and retention of IgA + MARPs in the lungs.