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Rajasundaram, D.

Publications and source records attributed to Rajasundaram, D..

11 recordsLinked to original sources

Genome-Wide Transcriptomics Uncovers a Lung-to-Aorta Inflammatory Program Driving Influenza-Induced Atherosclerosis Exacerbation

Influenza infection increases cardiovascular risk in individuals with pre-existing atherosclerosis, yet the genome-wide transcriptional basis of this association remains undefined. We performed bulk RNA sequencing of aorta and lung tissues from high-fat diet-fed Apoe-/- mice infected with influenza A/PR/8/34 versus PBS-treated controls at day 15 post-infection, identifying 6,828 differentially expressed genes across both tissues (5,694 in the lung and 1,134 in the aorta; adjusted p < 0.05). In the lung, influenza sustained a CXCR3-driven chemokine storm, comprehensive Th1, Th17, and exhaustion T-cell activation programs, coordinated monocyte recruitment through Ccl2, Ccl7, Ccl8, and Ccl12, a broad acute phase response including Saa3 and A2m, alveolar identity collapse through loss of Nkx2-1 and surfactant proteins, and broad metabolic dysregulation involving suppression of fatty acid oxidation, mitochondrial function, and circadian metabolic regulators. In the aorta, influenza drove macrophage and DAMP activation through Trem1, Fpr2, and S100a8, cytotoxic T-cell engagement, smooth muscle cell dedifferentiation through Myocd loss, convergent bioenergetic failure, and an ectopic lung-identity gene signature representing a previously undescribed cross-organ communication mechanism. Circadian clock and Hippo/YAP pathway suppression were shared across both tissues, identifying systemic vulnerabilities connecting pulmonary infection to vascular structural compromise. Consistent with the in vivo findings, influenza-infected Apoe-/- bone marrow-derived macrophages exhibited inflammasome activation, DAMP amplification, M1 polarization, and suppression of prostaglandin-mediated inflammatory resolution. Together these findings define a lung-to-aorta inflammatory and metabolic axis driving atherosclerotic plaque destabilization during the post-infection recovery period and identify CCR2/CXCR3 antagonism, NLRP3 inhibition, and YAP pathway activation as candidate therapeutic interventions.

immunology↗

Characterization of zebrafish nucleus pulposus in development and aging: A fish model for probing human intervertebral disc degeneration and regeneration

Intervertebral disc (IVD) degeneration (IDD) contributes to low back and neck pain. The nucleus pulposus (NP) of the IVD is usually degenerated first in age-related IDD. Addressing NP degeneration remains challenging due to insufficient understanding of its etiologies. Here, we characterize zebrafish IVD, particularly the NP, and note several characteristics that are common to or different from those of mammals. The adult zebrafish NP can be partitioned into three sections: the NP envelope with a monolayer of basal cells, the peripheral region with clustered vacuolated and non-vacuolated NP cells, and the central fibrotic region with low cellularity. With age, the percentage of vacuolated NP cells decreases, whereas that of non-vacuolated NP cells increases, as in mammals. However, a cluster of vacuolated cells persists in the NP periphery even in aged zebrafish. Notably, the ratio of the span of the fibrotic NP center to NP diameter remains largely constant at 50% regardless of age, suggesting that the zebrafish NP can better maintain its overall shape and structure, compared to mammalian NP. The fibrotic NP center and cell-populated NP periphery serve as internal controls to each other for studying NP maintenance and fibrosis. With external development, high fecundity, and great regenerative capabilities, zebrafish may be a unique NP model to complement mammalian models for studying how the NP degenerates and how the dormant capability of NP regeneration may be revitalized in humans.

developmental biology↗

Early-life Exposure to Arsenic Primes the Offspring to Increased Asthma Risk: Transcriptome and Epigenome Analysis

Inorganic arsenic (iAs) in drinking water is a global health concern. This study tests whether maternal exposure to iAs in drinking water at the WHO provisional level (10{micro}g/L) increases offspring asthma risk via epigenetic reprogramming. F1 mice prenatally exposed to iAs were analyzed at 5 months for blood transcriptome and methylome changes and challenged with house allergens before lung function testing. Prenatal iAs exposure led to increased airway hyperresponsiveness (AHR) and altered inflammation gene expression and DNA methylation changes. Notably, miR-101c was epigenetically reprogrammed early in development, with persistent downregulation in both target (fetal and adult lungs) and surrogate (amniotic fluid and blood) tissues. These changes correlated with increased allergic AHR and TGF{beta} pathway dysregulation. Findings suggest that maternal iAs exposure primes offspring for asthma risk through epigenetic alterations and may inform risk assessment and biomarker development in affected communities. KEY FINDINGSO_LIIn utero exposure to 10 part per billion (or 10 {micro}g/L, the current WHO and EPA provisional level in drinking water) inorganic arsenic (iAs) increases offspring asthma risk. These results raise concerns about the current safety thresholds for iAs in drinking water (Fig. 1). C_LIO_LITranscriptomic and methylome analyses of blood leukocytes from 5-month-old F1 mice revealed that maternal iAs exposure induces transcriptional changes in genes related to allergic airway responses. Pathway analysis highlighted the involvement of miR-101c and its connection with TGF{beta} downstream targets in regulating extracellular matrix signaling, embryonic development, and inflammatory (Figs. 2 and 3). C_LIO_LITranscriptional changes in col3a1 and miR-101c in blood were strongly correlated with allergen-induced airway hyperresponsiveness (AHR), with similar alterations detected in plasma samples. These findings provide new insights into respiratory health in affected communities and support the development of biomarkers for iAs risk assessment (Figs. 4 and 5). C_LIO_LISeveral gene-specific epigenetic alterations induced by early-life iAs exposure were consistently observed in both surrogate (blood) and target (lung) tissues across developmental stages, offering new panels of easily accessible markers for early detection and monitoring of lung disease risk in offspring. The persistence of these markers over time makes them valuable for predictive modeling and life course studies. (Fig. 6). C_LIO_LIDownregulation of miR-101c was validated in fetal lung and amniotic fluid of the iAs-exposed group, suggesting that epigenetic reprogramming of miR-101c is initiated early in gestation (Fig. 7). These findings help uncover causal pathways linking environmental exposures to asthma pathogenesis. C_LIO_LIDistinct sex-specific patterns in blood transcriptome and methylome alterations in respond to early-life iAs exposure underscore the importance of considering sex as a biological variable in omics research. C_LI O_FIG O_LINKSMALLFIG WIDTH=149 HEIGHT=200 SRC="FIGDIR/small/668223v1_fig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@1f5394eorg.highwire.dtl.DTLVardef@855bf8org.highwire.dtl.DTLVardef@1592328org.highwire.dtl.DTLVardef@1133ec4_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 1.C_FLOATNO Maternal iAs exposure and study design to assess offspring asthma risk. A) Schematic shows the exposure window in which F0 dams received iAs in drinking water from preconception through lactation, followed by collection of F1 progeny for transcriptomic and methylomic analysis. A subset of 5-month-old F1 progenies were assessed for the HDM allergen-induced airway reactivity and airway inflammation. B) Lung resistance was assessed following methacholine (30mg/mL) challenge. C) BAL cells were stained with Diff-Quick, and eosinophil counts are shown. Each datapoint represents a pup from an individual dam; error bars indicate SEM. Five to six dams were used. C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=119 SRC="FIGDIR/small/668223v1_fig2.gif" ALT="Figure 2"> View larger version (23K): org.highwire.dtl.DTLVardef@7dc1b1org.highwire.dtl.DTLVardef@378529org.highwire.dtl.DTLVardef@1076fe3org.highwire.dtl.DTLVardef@142d801_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 2.C_FLOATNO Blood transcriptome profiles and predicted canonical pathways and regulatory networks. A) Numbers of differentially expressed genes (DEGs) identified in male and female progeny are illustrated with a Venn diagram. Enriched canonical pathways ranked by the p value are shown. B) Using the set of DEGs common in both sexes, Ingenuity Pathway Analysis (IPA) highlights TGF as a central upstream regulator linking overlapping DEGs related to extracellular matrix signaling (orange), inflammation (yellow), and embryonic development/cell metabolism (blue). C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=131 SRC="FIGDIR/small/668223v1_fig3.gif" ALT="Figure 3"> View larger version (23K): org.highwire.dtl.DTLVardef@1732b53org.highwire.dtl.DTLVardef@216332org.highwire.dtl.DTLVardef@1f794d1org.highwire.dtl.DTLVardef@14b62df_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 3.C_FLOATNO Blood methylome analysis and associations between miR-101c and TGF-related differentially expressed genes. A) Number of differentially methylated CpGs (DMCs) identified in male and female progeny are illustrated with a Venn diagram. There are four DMCs overlapping DMCs annotated to miR-101c. B) Expression levels of miR-101c are shown. C) IPA-derived network linking this miRNA to TGF-related DEGs. Each datapoint represents a pup from an individual dam; error bars indicate SEM. Four to five dams were used. C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/668223v1_fig4.gif" ALT="Figure 4"> View larger version (38K): org.highwire.dtl.DTLVardef@482e86org.highwire.dtl.DTLVardef@e666bdorg.highwire.dtl.DTLVardef@631538org.highwire.dtl.DTLVardef@10618f6_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 4.C_FLOATNO Relationship between iAs-induced blood transcriptional changes and allergen-induced AHR. This figure presents correlation patterns between baseline blood DEGs expression changes prior to HDM challenge and subsequent changes in AHR. Pearson correlation coefficients are depicted using a color gradient to distinguish positive (blue) and negative (peach) associations. * Positive correlation: r>0.8, p<0.05; ^ negative correlation: r<-0.8, p<0.05 C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/668223v1_fig5.gif" ALT="Figure 5"> View larger version (20K): org.highwire.dtl.DTLVardef@150d27eorg.highwire.dtl.DTLVardef@12b4edeorg.highwire.dtl.DTLVardef@4702a8org.highwire.dtl.DTLVardef@1ff9600_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 5.C_FLOATNO Circulating miR-101c levels in progeny exposed to maternal iAs. Plasma levels of miR-101c and COL3A1 protein are shown at different developmental stages. A) Relative expression of miR-101c across F1 progeny at juvenile (3 weeks of age) and adult (5 months of age) prenatally exposed to iAs. B) Levels of COL3A1 protein are shown at juvenile and adult F1 progeny. Each datapoint represents a pup from an individual dam, error bars indicate SEM. C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=160 SRC="FIGDIR/small/668223v1_fig6.gif" ALT="Figure 6"> View larger version (46K): org.highwire.dtl.DTLVardef@d0ec76org.highwire.dtl.DTLVardef@5468a2org.highwire.dtl.DTLVardef@1a17e85org.highwire.dtl.DTLVardef@17956ce_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 6.C_FLOATNO Comparison of transcriptional patterns across tissues and developmental stages. Expression changes (FC: fold changes vs. unexposed) of DEGs and miR-101c are compared between blood and lung tissues in both A) juvenile (3 weeks of age) and B) adult (5 months of age) progeny. Blue and orange bars represent FC in blood from male and female progeny, respectively. Black bars represent FC in lung tissues. Solid bars indicate statistically significant changes. C_FIG O_FIG O_LINKSMALLFIG WIDTH=154 HEIGHT=200 SRC="FIGDIR/small/668223v1_fig7.gif" ALT="Figure 7"> View larger version (22K): org.highwire.dtl.DTLVardef@131ef23org.highwire.dtl.DTLVardef@14b0652org.highwire.dtl.DTLVardef@8c1b30org.highwire.dtl.DTLVardef@4cf6d9_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 7.C_FLOATNO Fetal lung and amniotic fluid levels of miR-101c. Relative levels of miR-101c are shown in fetal lung tissues and matched amniotic fluid at embryonic day 16. Data illustrate expression patterns in the context of maternal iAs exposure. Each datapoint represents a pup from an individual dam, error bars indicate SEM. C_FIG GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/668223v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@e25f49org.highwire.dtl.DTLVardef@1dddc22org.highwire.dtl.DTLVardef@9f4244org.highwire.dtl.DTLVardef@1b787e9_HPS_FORMAT_FIGEXP M_FIG C_FIG Description: F1 progeny prenatally exposed to iAs were assessed for blood transcriptomic and DNA methylome analysis at 5 months of age. Correlation analysis between transcriptional changes and allergen-induced airway hyperresponsiveness (AHR) was conducted to examine the epigenetic impact of maternal iAs exposure on offspring asthma risk.

genomics↗

Liver transplant rejection features memory cell priming, spatially differentiated networks and novel drug targets.

Acute T-cell-mediated transplant rejection, the earliest contributor to immunological graft failure responds variably to T-cell suppression. Early rejection can co-exist with donor-specific antibodies which also shorten graft survival, without affecting graft histology visibly. Here, during early liver transplant rejection, blood leukocytes manifest primed T-cells with heat shock protein (HSP) signaling and transcriptional programs for memory cell expansion. Corresponding biopsies demonstrate upregulated immune synapse and proteasomal genes in T-cell-infiltrated portal and central regions of the liver lobule. With donor-specific antibodies, the intervening intralobular region demonstrates a germinal-center-like allograft response with upregulated CD40, chemokine, T-follicular and complement signaling, which intensifies along the direction of sinusoidal blood flow from portal to central regions. Proteasomal and HSP90 inhibitors suppress donor-specific alloresponses of T- and B-cells in blood samples from patients with early rejection. The molecular injury spectrum of early rejection is complex, spatially differentiated and reveals novel early immunosuppressive strategies to extend graft survival.

immunology↗

Cited4a limits cardiomyocyte dedifferentiation and proliferation during zebrafish heart regeneration

Cardiac regeneration involves the interplay of complex interactions between many different cell types, including cardiomyocytes. The exact mechanism that enables cardiomyocytes to undergo dedifferentiation and proliferation to replace lost cells has been intensely studied. Here we report a single nuclear RNA sequencing profile of the injured zebrafish heart and identify distinct cardiomyocyte populations in the injured heart. These cardiomyocyte populations have diverse functions, including stress response, myofibril assembly, proliferation and contraction. The contracting cardiomyocyte population also involves the activation of maturation pathways as an early response to injury. This intriguing finding suggests that constant maintenance of a distinctive terminally differentiated cardiomyocyte population is important for cardiac function during regeneration. To test this hypothesis, we determined that cited4a, a p300/CBP transcriptional coactivator, is induced after injury in the mature cardiomyocyte population. Moreover, loss-of-cited4a mutants presented increased dedifferentiation, proliferation and accelerated heart regeneration. Thus, suppressing cardiomyocyte maturation pathway activity in injured hearts could be an approach to promote heart regeneration.

developmental biology↗

Hypomorphic NOTCH1 Expression Alters Cardiomyocyte Cellular Architecture in Hypoplastic Left Heart Syndrome

NOTCH1 is a protein involved in cardiac development and mutations in NOTCH1 are implicated in left sided congenital heart disease, including hypoplastic left heart syndrome (HLHS). Therapeutic advances for HLHS patients have been hampered by the absence of suitable experimental models. Here, using human induced pluripotent stem cells (hiPSCs), we have generated a series of CRISPR-edited complex heterozygous hypomorphic mutations in NOTCH1 that recapitulate mutations seen in HLHS patients. These cells demonstrate the downregulation of genes associated with mitochondria, the actin cytoskeleton, and cardiomyocyte development. In addition, these hypomorphic NOTCH1 hiPSCs cells showed an increased propensity to differentiate towards non-cardiomyocyte lineages such as fibroblasts and smooth muscle cells, a finding confirmed in HLHS patient-derived myocardial tissue. Abnormalities in sarcomeric and mitochondrial architecture contributed to decreased ATP production, abnormal calcium transients, and reduced contractility. Using a split nano-luciferase system as a NOTCH1 intracellular reporter, we screened a library of FDA-approved compounds. Auranofin, an agent currently employed for rheumatoid arthritis, was identified as a candidate drug that could rescue impaired differentiation and contractility seen in the hypomorphic NOTCH1 model. These findings point to cell-autonomous abnormalities in hypomorphic NOTCH1 pre-cardiomyocyte cells that can be leveraged to identify potential therapeutic strategies for patients with severe congenital cardiac abnormalities. HighlightsO_LICRISPR edited and patient-derived iPSCs with hypomorphic NOTCH1 expression were used to characterize a cell-based model of hypoplastic left heart syndrome. C_LIO_LIHypomorphic NOTCH1 iPSCs have abnormalities in pathways associated with mitochondrial function, actin cytoskeleton, and cardiomyocyte development. C_LIO_LIHypomorphic NOTCH1 iPSCs have less pluripotency and tend to skew differentiation away from cardiomyocytes and towards fibroblasts and smooth muscle cells. C_LIO_LINOTCH1 is required for cardiac cytoskeletal and mitochondrial architecture, and to preserve contractility and ATP production. C_LIO_LIA high-throughput drug screen identified auranofin as an agent that may benefit patients with hypoplastic left heart syndrome. C_LI

cell biology↗

CCR7+ CD4 T Cell Immunosurveillance Disrupted in Chronic SIV-Induced Neuroinflammation in Rhesus Brain.

CD4 T cells survey and maintain immune homeostasis in the brain, yet their differentiation states and functional capabilities remain unclear. Our approach, combining single-cell transcriptomic analysis, ATAC-seq, spatial transcriptomics, and flow cytometry, revealed a distinct subset of CCR7+ CD4 T cells resembling lymph node central memory (TCM) cells. We observed chromatin accessibility at the CCR7, CD28, and BCL-6 loci, defining molecular features of TCM. Brain CCR7+ CD4 T cells exhibited recall proliferation and interleukin-2 production ex vivo, showcasing their functional competence. We identified the skull bone marrow as a local niche for these cells alongside other CNS border tissues. Sequestering TCM cells in lymph nodes using FTY720 led to reduced CCR7+ CD4 T cell frequencies in the cerebrospinal fluid, accompanied by increased monocyte levels and soluble markers indicating immune activation. In macaques chronically infected with SIVCL57 and experiencing viral rebound due to cessation of antiretroviral therapy, a decrease in brain CCR7+ CD4 T cells was observed, along with increased microglial activation and initiation of neurodegenerative pathways. Our findings highlight a role for CCR7+ CD4 T cells in CNS immune surveillance and their decline during chronic SIV-induced neuroinflammation highlights their responsiveness to neuroinflammatory processes. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=87 SRC="FIGDIR/small/555037v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@191f9caorg.highwire.dtl.DTLVardef@a67d2dorg.highwire.dtl.DTLVardef@645443org.highwire.dtl.DTLVardef@d81fd6_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefUtilizing single-cell and spatial transcriptomics on adult rhesus brain, we uncover a unique CCR7+ CD4 T cell subset resembling central memory T cells (TCM) within brain and border tissues, including skull bone marrow. Our findings show decreased frequencies of this subset during SIV- induced chronic neuroinflammation, emphasizing responsiveness of CCR7+ CD4 T cells to CNS disruptions. HighlightsO_LICCR7+ CD4 T cells survey border and parenchymal CNS compartments during homeostasis; reduced presence of CCR7+ CD4 T cells in cerebrospinal fluid leads to immune activation, implying a role in neuroimmune homeostasis. C_LIO_LICNS CCR7+ CD4 T cells exhibit phenotypic and functional features of central memory T cells (TCM) including production of interleukin 2 and the capacity for rapid recall proliferation. Furthermore, CCR7+ CD4 T cells reside in the skull bone marrow. C_LIO_LICCR7+ CD4 T cells are markedly decreased within the brain parenchyma during chronic viral neuroinflammation. C_LI

neuroscience↗

CD4 T cell Responses in the CNS during SIV infection

Virologic suppression with antiretroviral therapy (ART) has significantly improved health outcomes for people living with HIV, yet challenges related to chronic inflammation in the central nervous system (CNS) - known as Neuro-HIV-persist. As primary targets for HIV-1 with the ability to survey and populate the CNS and interact with myeloid cells to co-ordinate neuroinflammation, CD4 T cells are pivotal in Neuro-HIV. Despite their importance, our understanding of CD4 T cell distribution in virus-targeted CNS tissues, their response to infection, and potential recovery following initiation of ART remain limited. To address these gaps, we studied ten SIVmac251-infected rhesus macaques using an ART regimen simulating suboptimal adherence. We evaluated four macaques during the acute phase pre-ART and six during the chronic phase. Our data revealed that HIV target CCR5+ CD4 T cells inhabit both the brain parenchyma and adjacent CNS tissues, encompassing choroid plexus stroma, dura mater, and the skull bone marrow. Aligning with the known susceptibility of CCR5+ CD4 T cells to viral infection and their presence within the CNS, high levels of viral RNA were detected in the brain parenchyma and its border tissues during acute SIV infection. Single-cell RNA sequencing of CD45+ cells from the brain revealed colocalization of viral transcripts within CD4 clusters and significant activation of antiviral molecules and specific effector programs within T cells, indicating CNS CD4 T cell engagement during infection. Despite viral suppression with ART, acute infection led to significant depletion of CNS CD4 T cells, persisting into the chronic phase. These findings underscore the functional involvement of CD4 T cells within the CNS during SIV infection, enhancing our understanding of their role in establishing CNS viral presence. Our results offer insights for potential T cell-focused interventions while also underscoring the challenges in eradicating HIV from the CNS, even with effective ART. AUTHOR SUMMARYAntiretroviral therapy (ART) has improved health outcomes of people living with HIV. However, there are still challenges, especially in the central nervous system (CNS), where ongoing inflammation can lead to neurological disorders. Our study focused on understanding the role of CD4 T cells in the brain during HIV infection and treatment. We used a model with SIV-infected rhesus monkeys to study the AIDS virus in the brain and surrounding tissues. We discovered that a subset of CD4 T cells, which are vulnerable to HIV, are present throughout the CNS. During the early stages of infection, we noticed high levels of the virus in both the brain and nearby tissues. By examining these CD4 T cells at a single-cell level, we found that they actively respond to the virus by activating specific antiviral effector functions to fight it. Although ART controlled virus replication in the brain, CD4 T cells were continuously depleted, indicative of immune perturbations. Overall, our study helps us understand the role of CD4 T cells within the CNS during both acute and chronic HIV infection. This knowledge could help us develop new ways to target the virus in the CNS and devise treatments for complications related to Neuro-HIV.

neuroscience↗

The AKT2/SIRT5/TFEB pathway as a potential therapeutic target in atrophic AMD

Introductory paragraphAge-related macular degeneration (AMD), the leading cause of geriatric blindness, is a multi-factorial disease with retinal-pigmented epithelial (RPE) cell dysfunction as a central pathogenic driver. With RPE degeneration, lysosomal function is a core process that is disrupted. Transcription factors EB/E3 (TFEB/E3) tightly control lysosomal function; their disruption can cause aging disorders, such as AMD. Here, we show that induced pluripotent stem cells (iPSC)-derived RPE cells with the complement factor H variant [CFH (Y402H)] have increased AKT2, which impairs TFEB/TFE3 nuclear translocation and lysosomal function. Increased AKT2 can inhibit PGC1, which downregulates SIRT5, an AKT2 binding partner. SIRT5 and AKT2 co-regulate each other, thereby modulating TFEB-dependent lysosomal function in the RPE. Failure of the AKT2/SIRT5/TFEB pathway in the RPE induced abnormalities in the autophagy-lysosome cellular axis by upregulating secretory autophagy, thereby releasing a plethora of factors that likely contribute to drusen formation, a hallmark of AMD. Finally, overexpressing AKT2 in RPE cells in mice led to an AMD-like phenotype. Thus, targeting the AKT2/SIRT5/TFEB pathway could be a potential therapy for atrophic AMD.

cell biology↗

Tailoring Tfh Profiles Enhances Antibody Persistence to a Clade C HIV-1 Vaccine in Rhesus Macaques

CD4 T follicular helper cells (Tfh) are essential for establishing serological memory and have distinct helper attributes that impact both the quantity and quality of the antibody response. Insights into Tfh subsets that promote antibody persistence and functional capacity can critically inform vaccine design. Based on the Tfh profiles evoked by the live attenuated measles virus vaccine, renowned for its ability to establish durable humoral immunity, we investigated the potential of a Tfh1/17 recall response during the boost phase to enhance persistence of HIV-1 Envelope (Env) antibodies in rhesus macaques. Using a DNA-prime encoding gp160 antigen and Tfh polarizing cytokines (interferon protein-10 (IP-10) and interleukin-6 (IL-6)), followed by a gp140 protein boost formulated in a cationic liposome-based adjuvant (CAF01), we successfully generated germinal center (GC) Tfh1/17 cells. In contrast, a similar DNA-prime (including IP-10) followed by gp140 formulated with monophosphoryl lipid A (MPLA)+QS-21 adjuvant predominantly induced GC Tfh1 cells. While the generation of GC Tfh1/17 cells with CAF01 and GC Tfh1 cells with MPLA+QS-21 induced comparable peak Env antibodies, the latter group demonstrated significantly greater antibody concentrations at week 8 after final immunization which persisted up to 30 weeks (gp140 IgG ng/ml-MPLA; 5500; CAF01, 2155; p <0.05). Notably, interferon {gamma}+ Env-specific Tfh responses were consistently higher with gp140 in MPLA+QS-21 and positively correlated with Env antibody persistence. These findings suggest that vaccine platforms maximizing GC Tfh1 induction promote persistent Env antibodies, important for protective immunity against HIV.

immunology↗

Systemic immune dysfunction in cancer patients driven by IL6 and IL8 induction of an inhibitory receptor module in peripheral CD8+ T cells

Many cancer patients do not develop a durable response to the current standard of care immunotherapies despite substantial advances in targeting immune inhibitory receptors1-5. A potential compounding issue, which may serve as an unappreciated, dominant resistance mechanism, is an inherent systemic immune dysfunction that is often associated with advanced cancer6-12. Minimal response to inhibitory receptor (IR) blockade therapy and increased disease burden have been associated with peripheral CD8+ T cell dysfunction, characterized by suboptimal T cell proliferation and chronic expression of IRs (eg. Programmed Death 1 [PD1] and Lymphocyte Activation Gene 3 [LAG3])13, 14. Here, we demonstrate that up to a third of cancer patients express robust intracellular LAG3 (LAG3IC), but not surface LAG3 (LAG3SUR), in peripheral CD8+ T cells compared to CD4+ T cells and regulatory T cells (Tregs). LAG3IC is associated with: (i) expression of a LAG3IC-dominant IR module that includes PD1IC, NRP1IC, CD39IC, and TIGITIC; (ii) decreased CD8+ but not CD4+ T cell function that can be reversed by anti-LAG3 (and/or anti-PD1), despite limited constitutive surface IR expression; and (iii) poor disease prognosis. Systemic immune dysfunction is restricted to CD8+ T cells, including a high percentage of peripheral naive CD8+ T cells, indicating a TCR-independent mechanism that is driven by the cytokine IL6 and the chemokine IL8. Thus, the combination of an increased LAG3-dominant IR module and elevated systemic IL6 and/or IL8 may serve as predictive biomarkers and increase the possibility that cancer patients will benefit from therapeutic combinations targeting these systemic cytokines in the setting of PD1 and/or LAG3 blockade.

cancer biology↗