Oncolytic adenovirus encoding apolipoprotein A1 suppresses metastasis of triple-negative breast cancer in mice.

BACKGROUND: Dysregulation of cholesterol metabolism is associated with the metastasis of triple-negative breast cancer (TNBC). Apolipoprotein A1 (ApoA1) is widely recognized for its pivotal role in regulating cholesterol efflux and maintaining cellular cholesterol homeostasis. However, further exploration is needed to determine whether it inhibits TNBC metastasis by affecting cholesterol metabolism. Additionally, it is necessary to investigate whether ApoA1-based oncolytic virus therapy can be used to treat TNBC. METHODS: In vitro experiments and mouse breast cancer models were utilized to evaluate the molecular mechanism of ApoA1 in regulating cholesterol efflux and inhibiting breast cancer progression and metastasis. The gene encoding ApoA1 was inserted into the adenovirus genome to construct a recombinant adenovirus (ADV-ApoA1). Subsequently, the efficacy of ADV-ApoA1 in inhibiting the growth and metastasis of TNBC was evaluated in several mouse models, including orthotopic breast cancer, spontaneous breast cancer, and human xenografts. In addition, a comprehensive safety assessment of Syrian hamsters and rhesus monkeys injected with oncolytic adenovirus was conducted. RESULTS: This study found that dysregulation of cholesterol homeostasis is critical for the progression and metastasis of TNBC. In a mouse orthotopic model of TNBC, a high-cholesterol diet promoted lung and liver metastasis, which was associated with keratin 14 (KRT14), a protein responsible for TNBC metastasis. Furthermore, studies have shown that ApoA1, a cholesterol reverse transporter, inhibits TNBC metastasis by regulating the cholesterol/IKBKB/FOXO3a/KRT14 axis. Moreover, ADV-ApoA1 was found to promote cholesterol efflux, inhibit tumor growth, reduce lung metastasis, and prolonged the survival of mice with TNBC. Importantly, high doses of ADV-ApoA1 administered intravenously and subcutaneously were well tolerated in rhesus monkeys and Syrian hamsters. CONCLUSIONS: This study provides a promising oncolytic virus treatment strategy for TNBC based on targeting dysregulated cholesterol metabolism. It also establishes a basis for subsequent clinical trials of ADV-ApoA1 in the treatment of TNBC.

Physiological responses of European sea bass (Dicentrarchus labrax) exposed to increased carbon dioxide and reduced seawater salinities.

BACKGROUND: The iono- and osmoregulatory capacities of marine teleosts, such as European sea bass (Dicentrarchus labrax) are expected to be challenged by high carbon dioxide exposure, and the adverse effects of elevated CO2 could be amplified when such fish migrate into less buffered hypo-osmotic estuarine environments. Therefore, the effects of increased CO2 on the physiological responses of European sea bass (Dicentrarchus labrax) acclimated to 32 ppt, 10 ppt and 2.5 ppt were investigated. METHODS: Following acclimation to different salinities for two weeks, fish were exposed to present-day (400 µatm) and future (1000 µatm) atmospheric CO2 for 1, 3, 7 and 21 days. Blood pH, plasma ions (Na+, K+, Cl-), branchial mRNA expression of ion transporters such as Na+/K+-ATPase (NKA), Na+/K+/2Cl- co-transporters (NKCC) and ammonia transporters (e.g. Rhesus glycoproteins Rhbg, Rhcg1 and Rhcg2) were examined to understand the iono- and osmoregulatory consequences of elevated CO2. RESULTS: A transient but significant increase in the blood pH of exposed fish acclimated at 10 ppt (day 1) and 2.5 ppt (day 21) was observed possibly due to an overshoot of the blood HCO3- accumulation while a significant reduction of blood pH was observed after 21 days at 2.5ppt. However, no change was seen at 32 ppt. Generally, Na + concentration of control fish was relatively higher at 10 ppt and lower at 2.5 ppt compared to 32 ppt control group at all sampling periods. Additionally, NKA was upregulated in gill of juvenile sea bass when acclimated to lower salinities compared to 32 ppt control group. CO2 exposure generally downregulated NKA mRNA expression at 32ppt (day 1), 10 ppt (days 3, 7 and 21) and 2.5ppt (days 1 and 7) and also a significant reduction of NKCC mRNA level of the exposed fish acclimated at 32 ppt (1-3 days) and 10 ppt (7-21 days) was observed. Furthermore, Rhesus glycoproteins were generally upregulated in the fish acclimated at lower salinities indicating a higher dependance on gill ammonia excretion. Increased CO2 led to a reduced expression of Rhbg and may therefore reduce ammonia excretion rate. CONCLUSION: Juvenile sea bass were relatively successful in keeping acid base balance under an ocean acidification scenario. However, this came at a cost for ionoregulation with reduced NKA, NKCC and Rhbg expression rates as a consequence.

Early antiretroviral therapy in SIV-infected rhesus macaques reveals a multiphasic, saturable dynamic accumulation of the rebound competent viral reservoir.

The rebound competent viral reservoir (RCVR)-virus that persists during antiretroviral treatment (ART) and can reignite systemic infection when treatment is stopped-is the primary barrier to eradicating HIV. We used time to initiation of ART during primary infection of rhesus macaques (RMs) after intravenous challenge with barcoded SIVmac239 as a means to elucidate the dynamics of RCVR establishment in groups of RMs by creating a multi-log range of pre-ART viral loads and then assessed viral time-to-rebound and reactivation rates resulting from the discontinuation of ART after one year. RMs started on ART on days 3, 4, 5, 6, 7, 9 or 12 post-infection showed a nearly 10-fold difference in pre-ART viral measurements for successive ART-initiation timepoints. Only 1 of 8 RMs initiating ART on days 3 and 4 rebounded after ART interruption despite measurable pre-ART plasma viremia. Rebounding plasma from the 1 rebounding RM contained only a single barcode lineage detected at day 50 post-ART. All RMs starting ART on days 5 and 6 rebounded between 14- and 50-days post-ART with 1-2 rebounding variants each. RMs starting ART on days 7, 9, and 12 had similar time-to-measurable plasma rebound kinetics despite multiple log differences in pre-ART plasma viral load (pVL), with all RMs rebounding between 7- and 16-days post-ART with 3-28 rebounding lineages. Calculated reactivation rates per pre-ART pVL were highest for RMs starting ART on days 5, 6, and 7 after which the rate of accumulation of the RCVR markedly decreased for RMs treated on days 9 and 12, consistent with multiphasic establishment and near saturation of the RCVR within 2 weeks post infection. Taken together, these data highlight the heterogeneity of the RCVR between RMs, the stochastic establishment of the very early RCVR, and the saturability of the RCVR prior to peak viral infection.

Anti-PD-1 chimeric antigen receptor T cells efficiently target SIV-infected CD4+ T cells in germinal centers.

Programmed cell death protein 1 (PD-1) is an immune checkpoint marker commonly expressed on memory T cells and enriched in latently HIV-infected CD4+ T cells. We engineered an anti-PD-1 chimeric antigen receptor (CAR) to assess the impact of PD-1 depletion on viral reservoirs and rebound dynamics in SIVmac239-infected rhesus macaques (RMs). Adoptive transfer of anti-PD-1 CAR T cells was done in 2 SIV-naive and 4 SIV-infected RMs on antiretroviral therapy (ART). In 3 of 6 RMs, anti-PD-1 CAR T cells expanded and persisted for up to 100 days concomitant with the depletion of PD-1+ memory T cells in blood and tissues, including lymph node CD4+ follicular helper T (TFH) cells. Loss of TFH cells was associated with depletion of detectable SIV RNA from the germinal center (GC). However, following CAR T infusion and ART interruption, there was a marked increase in SIV replication in extrafollicular portions of lymph nodes, a 2-log higher plasma viremia relative to controls, and accelerated disease progression associated with the depletion of CD8+ memory T cells. These data indicate anti-PD-1 CAR T cells depleted PD-1+ T cells, including GC TFH cells, and eradicated SIV from this immunological sanctuary.

Broad-spectrum Delta-BA.2 tandem-fused heterodimer mRNA vaccine delivered by lipopolyplex.

Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, continues to mutate and generates new variants with increasingly severe immune escape, urging the upgrade of COVID-19 vaccines. Here, based on a similar dimeric RBD design as our previous ZF2001 vaccine, we developed a novel broad-spectrum COVID-19 mRNA vaccine, SWIM516, with chimeric Delta-BA.2 RBD dimer delivered by lipopolyplex (LPP). Unlike the popular lipid nanoparticle (LNP), this LPP-delivered mRNA expresses only in the injection site, which avoids potential toxicity to the liver. We demonstrated the broad-spectrum humoral and cellular immunogenicity of this vaccine to Delta and Omicron sub-variants in naïve mice and as booster shots. When challenged with Delta or Omicron live virus, vaccinated human angiotensin-converting enzyme (hACE2) transgenic mice and rhesus macaques were both protected, displaying significantly reduced viral loads and markedly relieved pathological damages. We believe the SWIM516 vaccine qualifies as a candidate for the next-generation broad-spectrum COVID-19 vaccine.

Superior protection in a relapsing Plasmodium cynomolgi rhesus macaque model by a chemoprophylaxis with sporozoite immunization regimen with atovaquone-proguanil followed by primaquine.

BACKGROUND: To gain a deeper understanding of protective immunity against relapsing malaria, this study examined sporozoite-specific T cell responses induced by a chemoprophylaxis with sporozoite (CPS) immunization in a relapsing Plasmodium cynomolgi rhesus macaque model. METHODS: The animals received three CPS immunizations with P. cynomolgi sporozoites, administered by mosquito bite, while under two anti-malarial drug regimens. Group 1 (n = 6) received artesunate/chloroquine (AS/CQ) followed by a radical cure with CQ plus primaquine (PQ). Group 2 (n = 6) received atovaquone-proguanil (AP) followed by PQ. After the final immunization, the animals were challenged with intravenous injection of 104 P. cynomolgi sporozoites, the dose that induced reliable infection and relapse rate. These animals, along with control animals (n = 6), were monitored for primary infection and subsequent relapses. Immunogenicity blood draws were done after each of the three CPS session, before and after the challenge, with liver, spleen and bone marrow sampling and analysis done after the challenge. RESULTS: Group 2 animals demonstrated superior protection, with two achieving protection and two experiencing partial protection, while only one animal in group 1 had partial protection. These animals displayed high sporozoite-specific IFN-γ T cell responses in the liver, spleen, and bone marrow after the challenge with one protected animal having the highest frequency of IFN-γ+ CD8+, IFN-γ+ CD4+, and IFN-γ+ γδ T cells in the liver. Partially protected animals also demonstrated a relatively high frequency of IFN-γ+ CD8+, IFN-γ+ CD4+, and IFN-γ+ γδ T cells in the liver. It is important to highlight that the second animal in group 2, which experienced protection, exhibited deficient sporozoite-specific T cell responses in the liver while displaying average to high T cell responses in the spleen and bone marrow. CONCLUSIONS: This research supports the notion that local liver T cell immunity plays a crucial role in defending against liver-stage infection. Nevertheless, there is an instance where protection occurs independently of T cell responses in the liver, suggesting the involvement of the liver's innate immunity. The relapsing P. cynomolgi rhesus macaque model holds promise for informing the development of vaccines against relapsing P. vivax.

Perceptography unveils the causal contribution of inferior temporal cortex to visual perception.

Neurons in the inferotemporal (IT) cortex respond selectively to complex visual features, implying their role in object perception. However, perception is subjective and cannot be read out from neural responses; thus, bridging the causal gap between neural activity and perception demands independent characterization of perception. Historically, though, the complexity of the perceptual alterations induced by artificial stimulation of IT cortex has rendered them impossible to quantify. To address this old problem, we tasked male macaque monkeys to detect and report optical impulses delivered to their IT cortex. Combining machine learning with high-throughput behavioral optogenetics, we generated complex and highly specific images that were hard for the animal to distinguish from the state of being cortically stimulated. These images, named "perceptograms" for the first time, reveal and depict the contents of the complex hallucinatory percepts induced by local neural perturbation in IT cortex. Furthermore, we found that the nature and magnitude of these hallucinations highly depend on concurrent visual input, stimulation location, and intensity. Objective characterization of stimulation-induced perceptual events opens the door to developing a mechanistic theory of visual perception. Further, it enables us to make better visual prosthetic devices and gain a greater understanding of visual hallucinations in mental disorders.

Human gene regulatory evolution is driven by the divergence of regulatory element function in both cis and trans.

Gene regulatory divergence between species can result from cis-acting local changes to regulatory element DNA sequences or global trans-acting changes to the regulatory environment. Understanding how these mechanisms drive regulatory evolution has been limited by challenges in identifying trans-acting changes. We present a comprehensive approach to directly identify cis- and trans-divergent regulatory elements between human and rhesus macaque lymphoblastoid cells using assay for transposase-accessible chromatin coupled to self-transcribing active regulatory region (ATAC-STARR) sequencing. In addition to thousands of cis changes, we discover an unexpected number (∼10,000) of trans changes and show that cis and trans elements exhibit distinct patterns of sequence divergence and function. We further identify differentially expressed transcription factors that underlie ∼37% of trans differences and trace how cis changes can produce cascades of trans changes. Overall, we find that most divergent elements (67%) experienced changes in both cis and trans, revealing a substantial role for trans divergence-alone and together with cis changes-in regulatory differences between species.

Transforming our understanding of species-specific gene regulation.

Mechanisms underlying phenotypic divergence across species remain unresolved. In this issue of Cell Genomics, Hansen, Fong, et al.1 systematically dissect human and rhesus macaque gene expression divergence by screening tens of thousands of orthologous elements for enhancer activity in lymphoblastoid cell lines, revealing a much greater role for trans divergence at levels equal to those of cis effects, counter to the prevailing consensus in the field.

Sex as a risk factor regarding presbyopia in the rhesus monkey.

PURPOSE: To determine the effect of sex as a risk factor regarding presbyopia. METHODS: Maximum accommodation was pharmacologically induced (40% cabachol corneal iontophoresis) in 97 rhesus monkeys (49 males and 48 females) ranging in age from 8 to 36 years old. Accommodation was measured by Hartinger coincidence refractometry. RESULTS: Accommodative amplitude measured refractometrically decreased with age, and the rate of change was not different between males and females (p = 0.827). CONCLUSIONS: Presbyopia is essentially sex neutral, and no one is spared. There may be modest variations between different populations for various reasons, but essentially it is monotonously predictable. At present there is no biological therapeutic.

Gastrointestinal microbiota and metabolites possibly contribute to distinct pathogenicity of SARS-CoV-2 proto or its variants in rhesus monkeys.

Gastrointestinal (GI) infection is evidenced with involvement in COVID-19 pathogenesis caused by SARS-CoV-2. However, the correlation between GI microbiota and the distinct pathogenicity of SARS-CoV-2 Proto and its emerging variants remains unclear. In this study, we aimed to determine if GI microbiota impacted COVID-19 pathogenesis and if the effect varied between SARS-CoV-2 Proto and its variants. We performed an integrative analysis of histopathology, microbiomics, and transcriptomics on the GI tract fragments from rhesus monkeys infected with SARS-CoV-2 proto or its variants. Based on the degree of pathological damage and microbiota profile in the GI tract, five of SARS-CoV-2 strains were classified into two distinct clusters, namely, the clusters of Alpha, Beta and Delta (ABD), and Proto and Omicron (PO). Notably, the abundance of potentially pathogenic microorganisms increased in ABD but not in the PO-infected rhesus monkeys. Specifically, the high abundance of UCG-002, UCG-005, and Treponema in ABD virus-infected animals positively correlated with interleukin, integrins, and antiviral genes. Overall, this study revealed that infection-induced alteration of GI microbiota and metabolites could increase the systemic burdens of inflammation or pathological injury in infected animals, especially in those infected with ABD viruses. Distinct GI microbiota and metabolite profiles may be responsible for the differential pathological phenotypes of PO and ABD virus-infected animals. These findings improve our understanding the roles of the GI microbiota in SARS-CoV-2 infection and provide important information for the precise prevention, control, and treatment of COVID-19.

Adaptive functions of structural variants in human brain development.

Quantifying the structural variants (SVs) in nonhuman primates could provide a niche to clarify the genetic backgrounds underlying human-specific traits, but such resource is largely lacking. Here, we report an accurate SV map in a population of 562 rhesus macaques, verified by in-house benchmarks of eight macaque genomes with long-read sequencing and another one with genome assembly. This map indicates stronger selective constrains on inversions at regulatory regions, suggesting a strategy for prioritizing them with the most important functions. Accordingly, we identified 75 human-specific inversions and prioritized them. The top-ranked inversions have substantially shaped the human transcriptome, through their dual effects of reconfiguring the ancestral genomic architecture and introducing regional mutation hotspots at the inverted regions. As a proof of concept, we linked APCDD1, located on one of these inversions and down-regulated specifically in humans, to neuronal maturation and cognitive ability. We thus highlight inversions in shaping the human uniqueness in brain development.

Long-term control of diabetes by tofacitinib-based immunosuppressive regimen after allo islet transplantation in diabetic rhesus monkeys that rejected previously transplanted porcine islets.

Porcine islet xenotransplantation has been highlighted as an alternative to allo islet transplantation. Despite the remarkable progress that has been made in porcine-islet pre-clinical studies in nonhuman primates, immunological tolerance to porcine islets has not been achieved to date. Therefore, allo islet transplantation could be required after the failure of porcine islet xenotransplantation. Here, we report the long-term control of diabetes by allogeneic pancreatic islet transplantation in diabetic rhesus monkeys that rejected previously transplanted porcine islets. Four diabetic male rhesus monkeys received the porcine islets and then allo islets (5700-19 000 IEQ/kg) were re-transplanted for a short or long period after the first xeno islet rejection. The recipient monkeys were treated with an immunosuppressive regimen consisting of ATG, humira, and anakinra for induction, and sirolimus and tofacitinib for maintenance therapy. The graft survival days of allo islets in these monkeys were >440, 395, >273, and 127, respectively, similar to that in allo islet transplanted cynomolgus monkeys that received the same immunosuppressive regimen without xeno sensitization. Taken together, it is likely that prior islet xenotransplantation does not affect the survival of subsequent allo islets under clinically applicable immunosuppressants.

Lethal dog attacks on adult rhesus macaques (Macaca mulatta) in an anthropogenic landscape.

For nonhuman primates living in anthropogenic areas, predation by larger predators is relatively rare. However, smaller predators, such as free-ranging as well as domesticated dogs, can shape the socioecology of urban nonhuman primates, either directly by attacking and killing them or indirectly by modifying their activity patterns. Here, we describe three (two probably fatal) cases of dog attacks on adult rhesus macaques inhabiting an anthropogenic landscape in Northern India and the circumstances surrounding these incidents. We discuss the importance of considering human presence and intervention in dog-nonhuman primate relationships while studying nonhuman primate populations across anthropogenic gradients, and its potential influences on group social dynamics and transmission of zoonotic agents.

Isolation of a recombinant simian adenovirus encoding the human adenovirus G52 hexon suggests a simian origin for human adenovirus G52.

Human adenoviruses (HAdVs) are causative agents of morbidity and mortality throughout the world. These double-stranded DNA viruses are phylogenetically classified into seven different species (A-G). HAdV-G52, originally isolated in 2008 from a patient presenting with gastroenteritis, is the sole human-derived member of species G. Phylogenetic analysis previously suggested that HAdV-G52 may have a simian origin, indicating a potential zoonotic spillover into humans. However, evidence of HAdV-G52 in either human or simian populations has not been reported since. Here, we describe the isolation and in vitro characterization of rhesus (rh)AdV-69, a novel simian AdV with clear evidence of recombination with HAdV-G52, from the stool of a rhesus macaque. Specifically, the rhAdV-69 hexon capsid protein is 100% identical to that of HAdV-G52, whereas the remainder of the genome is most similar to rhAdV-55, sharing 95.36% nucleic acid identity. A second recombination event with an unknown adenovirus (AdV) is evident at the short fiber gene. From the same sample, we also isolated a second, highly related recombinant AdV (rhAdV-68) that harbors a distinct hexon gene but nearly identical backbone compared to rhAdV-69. In vitro, rhAdV-68 and rhAdV-69 demonstrate comparable growth kinetics and tropisms in human cell lines, nonhuman cell lines, and human enteroids. Furthermore, we show that coinfection of highly related AdVs is not unique to this sample since we also isolated coinfecting rhAdVs from two additional rhesus macaque stool samples. Our data collectively contribute to elucidating the origins of HAdV-G52 and provide insights into the frequency of coinfections and subsequent recombination in AdV evolution.IMPORTANCEUnderstanding the host origins of adenoviruses (AdVs) is critical for public health as transmission of viruses from animals to humans can lead to emergent viruses. Recombination between animal and human AdVs can also produce emergent viruses. HAdV-G52 is the only human-derived member of the HAdV G species. It has been suggested that HAdV-G52 has a simian origin. Here, we isolated from a rhesus macaque, a novel rhAdV, rhAdV-69, that encodes a hexon protein that is 100% identical to that of HAdV-G52. This observation suggests that HAdV-G52 may indeed have a simian origin. We also isolated a highly related rhAdV, differing only in the hexon gene, from the same rhesus macaque stool sample as rhAdV-69, illustrating the potential for co-infection of closely related AdVs and recombination at the hexon gene. Furthermore, our study highlights the critical role of whole-genome sequencing in understanding AdV evolution and monitoring the emergence of pathogenic AdVs.

Rhesus infant nervous temperament predicts peri-adolescent central amygdala metabolism & behavioral inhibition measured by a machine-learning approach.

Anxiety disorders affect millions of people worldwide and impair health, happiness, and productivity on a massive scale. Developmental research points to a connection between early-life behavioral inhibition and the eventual development of these disorders. Our group has previously shown that measures of behavioral inhibition in young rhesus monkeys (Macaca mulatta) predict anxiety-like behavior later in life. In recent years, clinical and basic researchers have implicated the central extended amygdala (EAc)-a neuroanatomical concept that includes the central nucleus of the amygdala (Ce) and the bed nucleus of the stria terminalis (BST)-as a key neural substrate for the expression of anxious and inhibited behavior. An improved understanding of how early-life behavioral inhibition relates to an increased lifetime risk of anxiety disorders-and how this relationship is mediated by alterations in the EAc-could lead to improved treatments and preventive strategies. In this study, we explored the relationships between infant behavioral inhibition and peri-adolescent defensive behavior and brain metabolism in 18 female rhesus monkeys. We coupled a mildly threatening behavioral assay with concurrent multimodal neuroimaging, and related those findings to various measures of infant temperament. To score the behavioral assay, we developed and validated UC-Freeze, a semi-automated machine-learning (ML) tool that uses unsupervised clustering to quantify freezing. Consistent with previous work, we found that heightened Ce metabolism predicted elevated defensive behavior (i.e., more freezing) in the presence of an unfamiliar human intruder. Although we found no link between infant-inhibited temperament and peri-adolescent EAc metabolism or defensive behavior, we did identify infant nervous temperament as a significant predictor of peri-adolescent defensive behavior. Our findings suggest a connection between infant nervous temperament and the eventual development of anxiety and depressive disorders. Moreover, our approach highlights the potential for ML tools to augment existing behavioral neuroscience methods.

Decidual leukocytes respond to African lineage Zika virus infection with mild anti-inflammatory changes during acute infection in rhesus macaques.

Zika virus (ZIKV) can be vertically transmitted during pregnancy resulting in a range of adverse pregnancy outcomes. The decidua is commonly found to be infected by ZIKV, yet the acute immune response to infection remains understudied in vivo. We hypothesized that in vivo African-lineage ZIKV infection induces a pro-inflammatory response in the decidua. To test this hypothesis, we evaluated the decidua in pregnant rhesus macaques within the first two weeks following infection with an African-lineage ZIKV and compared our findings to gestationally aged-matched controls. Decidual leukocytes were phenotypically evaluated using spectral flow cytometry, and cytokines and chemokines were measured in tissue homogenates from the decidua, placenta, and fetal membranes. The results of this study did not support our hypothesis. Although ZIKV RNA was detected in the decidual tissue samples from all ZIKV infected dams, phenotypic changes in decidual leukocytes and differences in cytokine profiles suggest that the decidua undergoes mild anti-inflammatory changes in response to that infection. Our findings emphasize the immunological state of the gravid uterus as a relatively immune privileged site that prioritizes tolerance of the fetus over mounting a pro-inflammatory response to clear infection.

The receptor binding domain of SARS-CoV-2 Omicron subvariants targets Siglec-9 to decrease its immunogenicity by preventing macrophage phagocytosis.

The development of a vaccine specific to severe acute respiratory syndrome coronavirus 2 Omicron has been hampered due to its low immunogenicity. Here, using reverse mutagenesis, we found that a phenylalanine-to-serine mutation at position 375 (F375S) in the spike protein of Omicron to revert it to the sequence found in Delta and other ancestral strains significantly enhanced the immunogenicity of Omicron vaccines. Sequence FAPFFAF at position 371-377 in Omicron spike had a potent inhibitory effect on macrophage uptake of receptor-binding domain (RBD) nanoparticles or spike-pseudovirus particles containing this sequence. Omicron RBD enhanced binding to Siglec-9 on macrophages to impair phagocytosis and antigen presentation and promote immune evasion, which could be abrogated by the F375S mutation. A bivalent F375S Omicron RBD and Delta-RBD nanoparticle vaccine elicited potent and broad nAbs in mice, rabbits and rhesus macaques. Our research suggested that manipulation of the Siglec-9 pathway could be a promising approach to enhance vaccine response.

Prenatal delta-9-tetrahydrocannabinol exposure alters fetal neurodevelopment in rhesus macaques.

Prenatal cannabis use is associated with adverse offspring neurodevelopmental outcomes, however the underlying mechanisms are relatively unknown. We sought to determine the impact of chronic delta-9-tetrahydrocannabinol (THC) exposure on fetal neurodevelopment in a rhesus macaque model using advanced imaging combined with molecular and tissue studies. Animals were divided into two groups, control (n = 5) and THC-exposed (n = 5), which received a daily THC edible pre-conception and throughout pregnancy. Fetal T2-weighted MRI was performed at gestational days 85 (G85), G110, G135 and G155 to assess volumetric brain development. At G155, animals underwent cesarean delivery with collection of fetal cerebrospinal fluid (CSF) for microRNA (miRNA) studies and fetal tissue for histologic analysis. THC exposure was associated with significant age by sex interactions in brain growth, and differences in fetal brain histology suggestive of brain dysregulation. Two extracellular vesicle associated-miRNAs were identified in THC-exposed fetal CSF; pathway analysis suggests that these miRNAs are associated with dysregulated axonal guidance and netrin signaling. This data is indicative of subtle molecular changes consistent with the observed histological data, suggesting a potential role for fetal miRNA regulation by THC. Further studies are needed to determine whether these adverse findings correlate with long-term offspring neurodevelopmental health.