Biology subjects

Atif, J.

Publications and source records attributed to Atif, J..

6 recordsLinked to original sources

bioRxiv2026

HLiCA: An integrated cell atlas of the healthy human liver

The human liver is composed of a heterogeneous mix of cell types. How these distinct populations contribute individually and collectively to liver function remains poorly understood. Although single-cell technologies have advanced our understanding of liver biology, individual studies have often been limited by small donor cohorts and inconsistent cell type annotations. Integrating multiple datasets can overcome these challenges and better capture biological variability. We present the Human Liver Cell Atlas (HLiCA), an integrated reference of non-disease liver cells assembled from eight datasets across six research centers, encompassing more than 525,000 cells from 110 donors. Developed in collaboration with the Human Cell Atlas Liver Bionetwork, the HLiCA incorporates expert-curated cell annotations refined through community feedback and dedicated cell type annotation meetings. The HLiCA classifies cells into six lineages and expands the cell type resolution to include 47 distinct cell types. Starting from raw sequencing reads, we realigned all data and performed rigorous benchmarking to ensure robust integration across technical and biological variables. Genetic ancestry was inferred for all samples to evaluate the range of ancestral backgrounds represented in the atlas. The expanded cell type annotation enabled identification of previously unrecognized liver cell types, including NRXN1+ stromal cells. Their presence was validated using spatial transcriptomics, which localized NRXN1+ stromal cells to periportal regions. With the number of donors included in the HLiCA we were able to examine cell type specific associations with demographic covariates. In hepatocytes, drug metabolism genes showed differential expression between sexes, and in cholangiocytes, mucus-production genes varied with age. As the largest and most genetically diverse human liver cell atlas to date, the HLiCA provides a comprehensive, well-annotated reference for the field, annotated by expert consensus. This resource will enable deeper interrogation of liver cellular diversity, architecture, and function in the healthy human liver and serve as a reference to understand changes that occur with disease.

genomics↗

bioRxiv2026

High-resolution spatial transcriptomics of adult and pediatric human liver with Visium HD

The liver is composed of diverse cell populations that coordinate essential metabolic and immune functions. Single-cell transcriptomics has advanced characterization of liver cellular composition, but dissociation of tissue to single-cells can introduce biases through the enrichment or depletion of cell types. Spatial transcriptomics is a complementary approach to avoid inherent bias for cell populations and to add important spatial context. The Visium HD spatial transcriptomics technology from 10X Genomics enables high-resolution spatial mapping of gene expression in tissue samples with a bin width of 2{micro}m enabling quantification of transcripts at a sub-cellular resolution. We applied Visium HD to three healthy human liver donor samples, from two adult and one pediatric donor. We identified cell types by clustering 8{micro}m bins and integration with single-cell reference maps. Differential expression analyses identified spatially distinct gene expression resulting in development of a high-resolution map of the liver. This resource provides cell-level and spatially-resolved insights into the cellular and anatomical heterogeneity of the liver to serve as a resource for researchers to identify disease-specific spatial signatures and novel therapeutic targets.

genomics↗

bioRxiv2025

A Single-Cell Atlas Of Human Pediatric Liver Reveals Age-Related Hepatic Gene Signatures

Background & AimsThe liver plays a critical role in metabolism and immune function, yet the contributions of its heterogeneous cell types to these processes remain unclear. While most liver studies focus on adults, pediatric liver diseases often present differently, underscoring the need for age-specific research. Approach & ResultsTo better understand cellular drivers of childhood liver diseases, we generated single-cell RNA-seq (scRNA-seq) maps of the normal pediatric liver and used this map to examine disease-related populations in biopsies from pediatric patients with Intestinal Failure-Associated Liver Disease (IFALD). The normal pediatric liver map consists of 42,660 cells from 9 donors aged 2-17 years. Compared to normal adult liver (26,372 cells; 7 donors, age 26-69) pediatric livers exhibited differences in myeloid populations. Specifically, pediatric Kupffer-like cells (MARCO+C1QA+VSIG4+) exhibited higher expression of immune activation genes, including CCL4, CCL3 and IL1B. In vitro stimulation confirmed more IL1-{beta} secreting myeloid cells in pediatric versus adult livers, supporting these findings. Using the pediatric atlas as a reference, we analyzed three IFALD biopsies (11,969 cells; 3 donors, ages 4 months-9 years) and identified increased expression of fibrosis-associated genes (e.g., LY96) in Kupffer-like cells. Additionally, mesenchymal cells in IFALD showed fibrotic gene modules resembling adult liver cells more than healthy pediatric cells. These signatures, undetectable when comparing IFALD to adult liver alone, highlighting the value of a pediatric map. ConclusionsTaken together, our healthy pediatric liver atlas reveals distinct age-related signatures and provides background against which to interpret pediatric liver disease data. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/649149v2_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@8d4131org.highwire.dtl.DTLVardef@1b336d2org.highwire.dtl.DTLVardef@d43ddeorg.highwire.dtl.DTLVardef@29fadf_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

bioRxiv2025

A Single-Cell Woodchuck Liver Atlas Identifies Healthy and Disease-Related Cellular Programs Conserved in Human

BackgroundModel organisms allowing for longitudinal examinations of liver disease pathogenesis are pivotal for the development of new therapeutic modalities. The eastern North American woodchuck develops chronic hepatitis and liver cancer after woodchuck hepatitis virus (WHV) infection, mirroring aspects of the natural history of the human hepatitis B virus (HBV). However, the cellular landscape of the woodchuck liver and the cell-level relevance of WHV infection to HBV infection is currently uncharacterized. MethodsWe employed single-cell RNA sequencing (RNA-seq) to generate an atlas of healthy woodchuck liver (63,389 cells, n=8) and peripheral blood mononuclear cells (PBMCs) (26,972 cells, n=7). Cell-specific and hepatic zonation gene signatures were validated using spatial transcriptomics (n=1). We employed our atlas to examine immune activation in stimulated precision cut-liver slices (PCLS) and disease-related pathway activation in chronic WHV infection (11,797 cells, n=3). We further employed our atlas to examine shared disease pathways between WHV infection and human HBV infection. ResultsOur atlas revealed woodchuck hepatic cellular diversity comparable to human and murine livers. Applying single-nucleus RNA-seq to PMA/ionomycin-stimulated precision cut liver slices revealed inflammation-associated activation signatures in T cell, myeloid and endothelial cell compartment. Finally, we describe intrahepatic T cells in chronic WHV hepatitis with both exhaustion and activation-associated signatures that resemble intrahepatic T cell genes signatures described in human chronic HBV. ConclusionsWe present a multi-omic atlas of healthy, diseased and ex vivo stimulated woodchuck liver. By identifying shared pathological processes between WHV and HBV infections, our findings reinforce the value of this preclinical model in translational research. This resource aims to advance studies on HBV pathogenesis and oncogenesis to speed the development of novel therapeutic strategies. Impact and Implications/Lay summaryThe liver plays important roles in metabolism, detoxification, and immune processes; liver transplantation is often the only treatment option for severe chronic liver diseases. Therefore, developing animal models that reflect human liver disease and can be studied throughout the disease course is crucial for the discovery of new treatment options. The woodchuck is an animal that develops chronic hepatitis and liver cancer after infection with woodchuck hepatitis virus, which models the human hepatitis type B virus infection (HBV) and associated hepatic carcinoma. However, our understanding of the cells that compose the woodchuck liver is limited, making it challenging to design and test cell-based therapeutics. In this study, we atlased the healthy and chronically infected woodchuck liver, found that liver cell types in woodchuck resemble those in humans, and employed the atlas to show similarities between WHV and HBV at the cell level, reinforcing the potential of WHV-infected woodchuck as a model for human HBV disease. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC="FIGDIR/small/641192v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@18fdd40org.highwire.dtl.DTLVardef@6ccf2org.highwire.dtl.DTLVardef@7923e1org.highwire.dtl.DTLVardef@122a8d2_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2021

Single Cell, Single Nucleus and Spatial RNA Sequencing of the Human Liver Identifies Hepatic Stellate Cell and Cholangiocyte Heterogeneity

The critical functions of the human liver are coordinated through the interactions of hepatic parenchymal and non-parenchymal cells. Recent advances in single cell transcriptional approaches have enabled an examination of the human liver with unprecedented resolution. However, dissociation related cell perturbation can limit the ability to fully capture the human livers parenchymal cell fraction, which limits the ability to comprehensively profile this organ. Here, we report the transcriptional landscape of 73,295 cells from the human liver using matched single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq). The addition of snRNA-seq enabled the characterization of interzonal hepatocytes at single-cell resolution, revealed the presence of rare subtypes of hepatic stellate cells previously only seen in disease, and detection of cholangiocyte progenitors that had only been observed during in vitro differentiation experiments. However, T and B lymphocytes and NK cells were only distinguishable using scRNA-seq, highlighting the importance of applying both technologies to obtain a complete map of tissue-resident cell-types. We validated the distinct spatial distribution of the hepatocyte, cholangiocyte and stellate cell populations by an independent spatial transcriptomics dataset and immunohistochemistry. Our study provides a systematic comparison of the transcriptomes captured by scRNA-seq and snRNA-seq and delivers a high-resolution map of the parenchymal cell populations in the healthy human liver.

cell biology↗

bioRxiv2017

Maternal obesity alters uterine NK cell activity through a functional KIR2DL1/S1 imbalance

In pregnancy, uterine natural killer cells (uNK) play essential roles in coordinating uterine angiogenesis, blood vessel remodeling, and promoting maternal tolerance to fetal tissue. Deviances from a normal uterine microenvironment are thought to modify uNK function(s), limiting their ability to establish a healthy pregnancy. While maternal obesity has become a major health concern due to associations with adverse effects on fetal and maternal health, our understanding into how obesity contributes to poor pregnancy disorders is essentially unknown. Given the importance of uNK in pregnancy, this study sets out to examine if obesity affects uNK function. Using a cohort of pregnant women, we show that baseline activity of uNK from obese women is elevated, but that enhanced activity does not equate to increased killing potential. Instead, obesity associates with altered uNK production of angiogenic VEGF-A and PlGF. These changes coincide with alterations in NKp46+ and NKG2A+ uNK subsets and elevated expression of KIR2D(L1/S1/S3/S5) receptors. Detailed examination revealed that obesity leads to imbalances in KIR2DL1/S1 expression that together instruct altered responses to HLA-C2 antigen, including increased production of TNF. Together, these findings suggest that maternal obesity modulates uNK function by altering angiokine/cytokine production and the response to HLA-C2 antigen.

immunology↗