Biology subjects

Hsieh, L.

Publications and source records attributed to Hsieh, L..

4 recordsLinked to original sources

bioRxiv2022

High Frequencies of PD-1+TIM3+TIGIT+CTLA4+ Functionally Exhausted SARS-CoV-2-Specific CD4+ and CD8+ T Cells Associated with Severe Disease in Critically ill COVID-19 Patients

SARS-CoV-2-specific memory T cells that cross-react with common cold coronaviruses (CCCs) are present in both healthy donors and COVID-19 patients. However, whether these cross-reactive T cells play a role in COVID-19 pathogenesis versus protection remain to be fully elucidated. In this study, we characterized cross-reactive SARS-CoV-2-specific CD4+ and CD8+ T cells, targeting genome-wide conserved epitopes in a cohort of 147 non-vaccinated COVID-19 patients, divided into six groups based on the degrees of disease severity. We compared the frequency, phenotype, and function of these SARS-CoV-2-specific CD4+ and CD8+ T cells between severely ill and asymptomatic COVID-19 patients and correlated this with -CCCs and {beta}-CCCs co-infection status. Compared with asymptomatic COVID-19 patients, the severely ill COVID-19 patients and patients with fatal outcomes: (i) Presented a broad leukocytosis and a broad CD4+ and CD8+ T cell lymphopenia; (ii) Developed low frequencies of functional IFN-{gamma}-producing CD134+CD138+CD4+ and CD134+CD138+CD8+ T cells directed toward conserved epitopes from structural, non-structural and regulatory SARS-CoV-2 proteins; (iii) Displayed high frequencies of SARS-CoV-2-specific functionally exhausted PD-1+TIM3+TIGIT+CTLA4+CD4+ and PD-1+TIM3+TIGIT+CTLA4+CD8+ T cells; and (iv) Displayed similar frequencies of co-infections with {beta}-CCCs strains but significantly fewer co-infections with -CCCs strains. Interestingly, the cross-reactive SARS-CoV-2 epitopes that recalled the strongest CD4+ and CD8+ T cell responses in unexposed healthy donors (HD) were the most strongly associated with better disease outcome seen in asymptomatic COVID-19 patients. Our results demonstrate that, the critically ill COVID-19 patients displayed fewer co-infection with -CCCs strain, presented broad T cell lymphopenia and higher frequencies of cross-reactive exhausted SARS-CoV-2-specific CD4+ and CD8+ T cells. In contrast, the asymptomatic COVID-19 patients, appeared to present more co-infections with -CCCs strains, associated with higher frequencies of functional cross-reactive SARS-CoV-2-specific CD4+ and CD8+ T cells. These findings support the development of broadly protective, T-cell-based, multi-antigen universal pan-Coronavirus vaccines. KEY POINTSO_LIA broad lymphopenia and lower frequencies of SARS-CoV-2-specific CD4+ and CD8+ T-cells were associated with severe disease onset in COVID-19 patients. C_LIO_LIHigh frequencies of phenotypically and functionally exhausted SARS-CoV-2-specific CD4+ and CD8+ T cells, co-expressing multiple exhaustion markers, and targeting multiple structural, non-structural, and regulatory SARS-CoV-2 protein antigens, were detected in severely ill COVID-19 patients. C_LIO_LICompared to severely ill COVID-19 patients and to patients with fatal outcomes, the (non-vaccinated) asymptomatic COVID-19 patients presented more functional cross-reactive CD4+ and CD8+ T cells targeting conserved epitopes from structural, non-structural, and regulatory SARS-CoV-2 protein antigens. C_LIO_LIThe cross-reactive SARS-CoV-2 epitopes that recalled the strongest CD4+ and CD8+ T cell responses in unexposed healthy donors (HD) were the most strongly associated with better disease outcomes seen in asymptomatic COVID-19 patients. C_LIO_LICompared to severely ill COVID-19 patients and to patients with fatal outcomes, the (non-vaccinated) asymptomatic COVID-19 patients presented higher rates of co-infection with the -CCCs strains. C_LIO_LICompared to patients with mild or asymptomatic COVID-19, severely ill symptomatic patients and patients with fatal outcomes had more exhausted SARS-CoV-2-speccific CD4+ and CD8+ T cells that preferentially target cross-reactive epitopes that share high identity and similarity with the {beta}-CCCs strains. C_LI

immunology↗

bioRxiv2021

microRNA Expression Levels Change in Neonatal Patients During and After Exposure to Cardiopulmonary Bypass

ObjectivesThe systemic inflammation that occurs after exposure to cardiopulmonary bypass (CPB), which is especially severe in neonatal patients, is associated with poorer outcomes and is not well understood. In order to gain deeper insight into how exposure to bypass activates inflammatory responses in circulating leukocytes, we studied changes in microRNA (miRNA) expression during and after exposure to bypass. miRNAs are small non-coding RNAs that have important roles in modulating protein levels and function of cells. MethodsWe performed miRNA-Sequencing on leukocytes isolated from neonatal cardiopulmonary bypass patients (N=5) at 7 timepoints during the process of CPB, including prior to the initiation of bypass, during bypass, and at three time points during the first 24 hours after weaning from bypass. We identified significant differentially expressed miRNAs using generalized linear regression models, and miRNAs were defined as statistically significant using an FDR adjusted p <0.05. We identified gene targets of these miRNAs using the Targetscan database, and identified significantly enriched biological pathways for these gene targets. ResultsWe identified 54 miRNAs with differential expression during and after CPB. These miRNAs clustered into 3 groups, including miRNAs that were increased during and after CPB (3 miRNAs), miRNAs that decreased during and after CPB (10 miRNAs), and miRNAs that decreased during CPB but then increased 8-24 hours after CPB. 38.9% of the target genes of these miRNAs were significantly differentially expressed in our previous study. miRNAs with altered expression levels are predicted to significantly modulate pathways related to inflammation and signal transduction. ConclusionsThe unbiased profiling of the miRNA changes that occur in the circulating leukocytes of bypass patients provides deeper insight into the mechanisms that underpin the systemic inflammatory response that occurs in patients after exposure to cardiopulmonary bypass. These data will help the development of novel treatments and biomarkers for bypass associated inflammation.

developmental biology↗

bioRxiv2020

Genome-Wide Asymptomatic B-Cell, CD4+ and CD8+ T-Cell Epitopes, that are Highly Conserved Between Human and Animal Coronaviruses, Identified from SARS-CoV-2 as Immune Targets for Pre-Emptive Pan-Coronavirus Vaccines

Over the last two decades, there have been three deadly human outbreaks of Coronaviruses (CoVs) caused by emerging zoonotic CoVs: SARS-CoV, MERS-CoV, and the latest highly transmissible and deadly SARS-CoV-2, which has caused the current COVID-19 global pandemic. All three deadly CoVs originated from bats, the natural hosts, and transmitted to humans via various intermediate animal reservoirs. Because there is currently no universal pan-Coronavirus vaccine available, two worst-case scenarios remain highly possible: (1) SARS-CoV-2 mutates and transforms into a seasonal "flu-like" global pandemic; and/or (2) Other global COVID-like pandemics will emerge in the coming years, caused by yet another spillover of an unknown zoonotic bat-derived SARS-like Coronavirus (SL-CoV) into an unvaccinated human population. Determining the antigen and epitope landscapes that are conserved among human and animal Coronaviruses as well as the repertoire, phenotype and function of B cells and CD4+ and CD8+ T cells that correlate with resistance seen in asymptomatic COVID-19 patients should inform in the development of pan-Coronavirus vaccines 1. In the present study, using several immuno-informatics and sequence alignment approaches, we identified several human B-cell, CD4+ and CD8+ T cell epitopes that are highly conserved in: (i) greater than 81,000 SARS-CoV-2 human strains identified to date in 190 countries on six continents; (ii) six circulating CoVs that caused previous human outbreaks of the "Common Cold"; (iii) five SL-CoVs isolated from bats; (iv) five SL-CoV isolated from pangolins; (v) three SL-CoVs isolated from Civet Cats; and (vi) four MERS strains isolated from camels. Furthermore, we identified cross-reactive asymptomatic epitopes that: (i) recalled B cell, CD4+ and CD8+ T cell responses from both asymptomatic COVID-19 patients and healthy individuals who were never exposed to SARS-CoV-2; and (ii) induced strong B cell and T cell responses in "humanized" Human Leukocyte Antigen (HLA)-DR/HLA-A*02:01 double transgenic mice. The findings herein pave the way to develop a pre-emptive multi-epitope pan-Coronavirus vaccine to protect against past, current, and potential future outbreaks.

immunology↗

bioRxiv2019

Ectopic HCN4 expression drives mTOR-dependent epilepsy

The causative link between focal cortical malformations (FCM) and epilepsy is well-accepted, especially among patients with focal cortical dysplasia type II (FCDII) and tuberous sclerosis complex (TSC). However, the mechanisms underlying seizures remain unclear. Using a mouse model of TSC- and FCDII-associated FCM, we show that FCM neurons are responsible for seizure activity via their unexpected abnormal expression of the hyperpolarization-activated cyclic nucleotide-gated potassium channel isoform 4 (HCN4), which is normally not present in cortical pyramidal neurons after birth. Increasing intracellular cAMP levels, which preferentially affects HCN4 gating relative to the other isoforms, drove repetitive firing of FCM neurons but not that of control pyramidal neurons. Ectopic HCN4 expression was mTOR-dependent, preceded the onset of seizures, and was also found in diseased neurons in tissue resected for epilepsy treatment from TSC and FCDII patients. Finally, blocking HCN4 channel activity in FCM neurons prevented epilepsy in mice. These findings that demonstrate HCN4 acquisition as seizure-genic, identify a novel cAMP-dependent seizure mechanism in TSC and FCDII. Furthermore, the unique expression of HCN4 exclusively in FCM neurons provides opportunities for using HCN4 as a gene therapy target to treat epilepsy in individuals with FCDII or TSC. One Sentence SummaryOur data provide a novel cAMP-dependent mechanism of seizure initiation in focal cortical dysplasia and tuberous sclerosis complex due to the unexpected ectopic expression of HCN4 channels only in diseased neurons. HCN4 channels are thus promising candidates for gene therapy to treat epilepsy generated by mTOR-driven focal malformations.

neuroscience↗