Homeostatic Control of Sebaceous Glands by Innate Lymphoid Cells Regulates Commensal Bacteria Equilibrium.

Immune cells and epithelium form sophisticated barrier systems in symbiotic relationships with microbiota. Evidence suggests that immune cells can sense microbes through intact barriers, but regulation of microbial commensalism remain largely unexplored. Here, we uncovered spatial compartmentalization of skin-resident innate lymphoid cells (ILCs) and modulation of sebaceous glands by a subset of RORγt+ ILCs residing within hair follicles in close proximity to sebaceous glands. Their persistence in skin required IL-7 and thymic stromal lymphopoietin, and localization was dependent on the chemokine receptor CCR6. ILC subsets expressed TNF receptor ligands, which limited sebocyte growth by repressing Notch signaling pathway. Consequently, loss of ILCs resulted in sebaceous hyperplasia with increased production of antimicrobial lipids and restricted commensalism of Gram-positive bacterial communities. Thus, epithelia-derived signals maintain skin-resident ILCs that regulate microbial commensalism through sebaceous gland-mediated tuning of the barrier surface, highlighting an immune-epithelia circuitry that facilitates host-microbe symbiosis.

Liquid Nuclear Condensates Mechanically Sense and Restructure the Genome.

Phase transitions involving biomolecular liquids are a fundamental mechanism underlying intracellular organization. In the cell nucleus, liquid-liquid phase separation of intrinsically disordered proteins (IDPs) is implicated in assembly of the nucleolus, as well as transcriptional clusters, and other nuclear bodies. However, it remains unclear whether and how physical forces associated with nucleation, growth, and wetting of liquid condensates can directly restructure chromatin. Here, we use CasDrop, a novel CRISPR-Cas9-based optogenetic technology, to show that various IDPs phase separate into liquid condensates that mechanically exclude chromatin as they grow and preferentially form in low-density, largely euchromatic regions. A minimal physical model explains how this stiffness sensitivity arises from lower mechanical energy associated with deforming softer genomic regions. Targeted genomic loci can nonetheless be mechanically pulled together through surface tension-driven coalescence. Nuclear condensates may thus function as mechano-active chromatin filters, physically pulling in targeted genomic loci while pushing out non-targeted regions of the neighboring genome. VIDEO ABSTRACT.

Structural basis of a transcription pre-initiation complex on a divergent promoter.

Most eukaryotic promoter regions are divergently transcribed. As the RNA polymerase II pre-initiation complex (PIC) is intrinsically asymmetric and responsible for transcription in a single direction, it is unknown how divergent transcription arises. Here, the Saccharomyces cerevisiae Mediator complexed with a PIC (Med-PIC) was assembled on a divergent promoter and analyzed by cryoelectron microscopy. The structure reveals two distinct Med-PICs forming a dimer through the Mediator tail module, induced by a homodimeric activator protein localized near the dimerization interface. The tail dimer is associated with ∼80-bp upstream DNA, such that two flanking core promoter regions are positioned and oriented in a suitable form for PIC assembly in opposite directions. Also, cryoelectron tomography visualized the progress of the PIC assembly on the two core promoter regions, providing direct evidence for the role of the Med-PIC dimer in divergent transcription.

A hyper-quiescent chromatin state formed during aging is reversed by regeneration.

Epigenetic alterations are a key hallmark of aging but have been limitedly explored in tissues. Here, using naturally aged murine liver as a model and extending to other quiescent tissues, we find that aging is driven by temporal chromatin alterations that promote a refractory cellular state and compromise cellular identity. Using an integrated multi-omics approach and the first direct visualization of aged chromatin, we find that globally, old cells show H3K27me3-driven broad heterochromatinization and transcriptional suppression. At the local level, site-specific loss of H3K27me3 over promoters of genes encoding developmental transcription factors leads to expression of otherwise non-hepatocyte markers. Interestingly, liver regeneration reverses H3K27me3 patterns and rejuvenates multiple molecular and physiological aspects of the aged liver.

Femtosecond proton transfer in urea solutions probed by X-ray spectroscopy.

Proton transfer is one of the most fundamental events in aqueous-phase chemistry and an emblematic case of coupled ultrafast electronic and structural dynamics1,2. Disentangling electronic and nuclear dynamics on the femtosecond timescales remains a formidable challenge, especially in the liquid phase, the natural environment of biochemical processes. Here we exploit the unique features of table-top water-window X-ray absorption spectroscopy3-6 to reveal femtosecond proton-transfer dynamics in ionized urea dimers in aqueous solution. Harnessing the element specificity and the site selectivity of X-ray absorption spectroscopy with the aid of ab initio quantum-mechanical and molecular-mechanics calculations, we show how, in addition to the proton transfer, the subsequent rearrangement of the urea dimer and the associated change of the electronic structure can be identified with site selectivity. These results establish the considerable potential of flat-jet, table-top X-ray absorption spectroscopy7,8 in elucidating solution-phase ultrafast dynamics in biomolecular systems.

Archaic chaperone-usher pili self-secrete into superelastic zigzag springs.

Adhesive pili assembled through the chaperone-usher pathway are hair-like appendages that mediate host tissue colonization and biofilm formation of Gram-negative bacteria1-3. Archaic chaperone-usher pathway pili, the most diverse and widespread chaperone-usher pathway adhesins, are promising vaccine and drug targets owing to their prevalence in the most troublesome multidrug-resistant pathogens1,4,5. However, their architecture and assembly-secretion process remain unknown. Here, we present the cryo-electron microscopy structure of the prototypical archaic Csu pilus that mediates biofilm formation of Acinetobacter baumannii-a notorious multidrug-resistant nosocomial pathogen. In contrast to the thick helical tubes of the classical type 1 and P pili, archaic pili assemble into an ultrathin zigzag architecture secured by an elegant clinch mechanism. The molecular clinch provides the pilus with high mechanical stability as well as superelasticity, a property observed for the first time, to our knowledge, in biomolecules, while enabling a more economical and faster pilus production. Furthermore, we demonstrate that clinch formation at the cell surface drives pilus secretion through the outer membrane. These findings suggest that clinch-formation inhibitors might represent a new strategy to fight multidrug-resistant bacterial infections.

Naa10p Inhibits Beige Adipocyte-Mediated Thermogenesis through N-α-acetylation of Pgc1α.

Diet-induced obesity can be caused by impaired thermogenesis of beige adipocytes, the brown-like adipocytes in white adipose tissue (WAT). Promoting brown-like features in WAT has been an attractive therapeutic approach for obesity. However, the mechanism underlying beige adipocyte formation is largely unknown. N-α-acetyltransferase 10 protein (Naa10p) catalyzes N-α-acetylation of nascent proteins, and overexpression of human Naa10p is linked to cancer development. Here, we report that both conventional and adipose-specific Naa10p deletions in mice result in increased energy expenditure, thermogenesis, and beige adipocyte differentiation. Mechanistically, Naa10p acetylates the N terminus of Pgc1α, which prevents Pgc1α from interacting with Pparγ to activate key genes, such as Ucp1, involved in beige adipocyte function. Consistently, fat tissues of obese human individuals show higher NAA10 expression. Thus, Naa10p-mediated N-terminal acetylation of Pgc1α downregulates thermogenic gene expression, making inhibition of Naa10p enzymatic activity a potential strategy for treating obesity.

Novel transient cytoplasmic rings stabilize assembling bacterial flagellar motors.

The process by which bacterial cells build their intricate flagellar motility apparatuses has long fascinated scientists. Our understanding of this process comes mainly from studies of purified flagella from two species, Escherichia coli and Salmonella enterica. Here, we used electron cryo-tomography (cryo-ET) to image the assembly of the flagellar motor in situ in diverse Proteobacteria: Hylemonella gracilis, Helicobacter pylori, Campylobacter jejuni, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Shewanella oneidensis. Our results reveal the in situ structures of flagellar intermediates, beginning with the earliest flagellar type III secretion system core complex (fT3SScc) and MS-ring. In high-torque motors of Beta-, Gamma-, and Epsilon-proteobacteria, we discovered novel cytoplasmic rings that interact with the cytoplasmic torque ring formed by FliG. These rings, associated with the MS-ring, assemble very early and persist until the stators are recruited into their periplasmic ring; in their absence the stator ring does not assemble. By imaging mutants in Helicobacter pylori, we found that the fT3SScc proteins FliO and FliQ are required for the assembly of these novel cytoplasmic rings. Our results show that rather than a simple accretion of components, flagellar motor assembly is a dynamic process in which accessory components interact transiently to assist in building the complex nanomachine.

An apical membrane complex for triggering rhoptry exocytosis and invasion in Toxoplasma.

Apicomplexan parasites possess secretory organelles called rhoptries that undergo regulated exocytosis upon contact with the host. This process is essential for the parasitic lifestyle of these pathogens and relies on an exocytic machinery sharing structural features and molecular components with free-living ciliates. However, how the parasites coordinate exocytosis with host interaction is unknown. Here, we performed a Tetrahymena-based transcriptomic screen to uncover novel exocytic factors in Ciliata and conserved in Apicomplexa. We identified membrane-bound proteins, named CRMPs, forming part of a large complex essential for rhoptry secretion and invasion in Toxoplasma. Using cutting-edge imaging tools, including expansion microscopy and cryo-electron tomography, we show that, unlike previously described rhoptry exocytic factors, TgCRMPs are not required for the assembly of the rhoptry secretion machinery and only transiently associate with the exocytic site-prior to the invasion. CRMPs and their partners contain putative host cell-binding domains, and CRMPa shares similarities with GPCR proteins. Collectively our data imply that the CRMP complex acts as a host-molecular sensor to ensure that rhoptry exocytosis occurs when the parasite contacts the host cell.

High-throughput cryo-ET structural pattern mining by unsupervised deep iterative subtomogram clustering.

Cryoelectron tomography directly visualizes heterogeneous macromolecular structures in their native and complex cellular environments. However, existing computer-assisted structure sorting approaches are low throughput or inherently limited due to their dependency on available templates and manual labels. Here, we introduce a high-throughput template-and-label-free deep learning approach, Deep Iterative Subtomogram Clustering Approach (DISCA), that automatically detects subsets of homogeneous structures by learning and modeling 3D structural features and their distributions. Evaluation on five experimental cryo-ET datasets shows that an unsupervised deep learning based method can detect diverse structures with a wide range of molecular sizes. This unsupervised detection paves the way for systematic unbiased recognition of macromolecular complexes in situ.

Rare coding variants in 35 genes associate with circulating lipid levels-A multi-ancestry analysis of 170,000 exomes.

Large-scale gene sequencing studies for complex traits have the potential to identify causal genes with therapeutic implications. We performed gene-based association testing of blood lipid levels with rare (minor allele frequency < 1%) predicted damaging coding variation by using sequence data from >170,000 individuals from multiple ancestries: 97,493 European, 30,025 South Asian, 16,507 African, 16,440 Hispanic/Latino, 10,420 East Asian, and 1,182 Samoan. We identified 35 genes associated with circulating lipid levels; some of these genes have not been previously associated with lipid levels when using rare coding variation from population-based samples. We prioritize 32 genes in array-based genome-wide association study (GWAS) loci based on aggregations of rare coding variants; three (EVI5, SH2B3, and PLIN1) had no prior association of rare coding variants with lipid levels. Most of our associated genes showed evidence of association among multiple ancestries. Finally, we observed an enrichment of gene-based associations for low-density lipoprotein cholesterol drug target genes and for genes closest to GWAS index single-nucleotide polymorphisms (SNPs). Our results demonstrate that gene-based associations can be beneficial for drug target development and provide evidence that the gene closest to the array-based GWAS index SNP is often the functional gene for blood lipid levels.

Toward a pan-SARS-CoV-2 vaccine targeting conserved epitopes on spike and non-spike proteins for potent, broad and durable immune responses.

BACKGROUND: The SARS-CoV-2 non-Spike (S) structural protein targets on nucleocapsid (N), membrane (M) and envelope (E), critical in the host cell interferon response and memory T-cell immunity, are grossly overlooked in COVID vaccine development. The current Spike-only vaccines bear an intrinsic shortfall for promotion of a fuller T cell immunity. Vaccines designed to target conserved epitopes could elicit strong cellular immune responses that would synergize with B cell responses and lead to long-term vaccine success. We pursue a universal (pan-SARS-CoV-2) vaccine against Delta, Omicrons and ever-emergent new mutants. METHODS AND FINDINGS: We explored booster immunogenicity of UB-612, a multitope-vaccine that contains S1-RBD-sFc protein and sequence-conserved promiscuous Th and CTL epitope peptides on the Sarbecovirus N, M and S2 proteins. To a subpopulation (N = 1,478) of infection-free participants (aged 18-85 years) involved in a two-dose Phase-2 trial, a UB-612 booster (third dose) was administered 6-8 months after the second dose. The immunogenicity was evaluated at 14 days post-booster with overall safety monitored until the end of study. The booster induced high viral-neutralizing antibodies against live Wuhan WT (VNT50, 1,711) and Delta (VNT50, 1,282); and against pseudovirus WT (pVNT50, 11,167) vs. Omicron BA.1/BA.2/BA.5 variants (pVNT50, 2,314/1,890/854), respectively. The lower primary neutralizing antibodies in the elderly were uplifted upon boosting to approximately the same high level in young adults. UB-612 also induced potent, durable Th1-oriented (IFN-γ+-) responses (peak/pre-boost/post-boost SFU/106 PBMCs, 374/261/444) along with robust presence of cytotoxic CD8+ T cells (peak/pre-boost/post-boost CD107a+-Granzyme B+, 3.6%/1.8%/1.8%). This UB-612 booster vaccination is safe and well tolerated without SAEs. CONCLUSIONS: By targeting conserved epitopes on viral S2, M and N proteins, UB-612 could provide potent, broad and long-lasting B-cell and T-cell memory immunity and offers the potential as a universal vaccine to fend off Omicrons and new VoCs without resorting to Omicron-specific immunogens. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT04773067; ClinicalTrials.gov ID: NCT05293665; ClinicalTrials.gov ID: NCT05541861.

Light-wave dynamic control of magnetism.

The enigmatic interplay between electronic and magnetic phenomena observed in many early experiments and outlined in Maxwell's equations propelled the development of modern electromagnetism1. Today, the fully controlled evolution of the electric field of ultrashort laser pulses enables the direct and ultrafast tuning of the electronic properties of matter, which is the cornerstone of light-wave electronics2-7. By contrast, owing to the lack of first-order interaction between light and spin, the magnetic properties of matter can only be affected indirectly and on much longer timescales, through a sequence of optical excitations and subsequent rearrangement of the spin structure8-16. Here we introduce the regime of ultrafast coherent magnetism and show how the magnetic properties of a ferromagnetic layer stack can be manipulated directly by the electric-field oscillations of light, reducing the magnetic response time to an external stimulus by two orders of magnitude. To track the unfolding dynamics in real time, we develop an attosecond time-resolved magnetic circular dichroism detection scheme, revealing optically induced spin and orbital momentum transfer in synchrony with light-field-driven coherent charge relocation17. In tandem with ab initio quantum dynamical modelling, we show how this mechanism enables the simultaneous control of electronic and magnetic properties that are essential for spintronic functionality. Our study unveils light-field coherent control of spin dynamics and macroscopic magnetic moments in the initial non-dissipative temporal regime and establishes optical frequencies as the speed limit of future coherent spintronic applications, spin transistors and data storage media.

Topology Optimization Enables High-Q Metasurface for Color Selectivity.

Nonlocal metasurfaces, exemplified by resonant waveguide gratings (RWGs), spatially and angularly configure optical wavefronts through narrow-band resonant modes, unlike the broad-band and broad-angle responses of local metasurfaces. However, forward design techniques for RWGs remain constrained at lower efficiency. Here, we present a topology-optimized metasurface resonant waveguide grating (MRWG) composed of titanium dioxide on a glass substrate capable of operating simultaneously at red, yellow, green, and blue wavelengths. Through adjoint-based topology optimization, while considering nonlocal effects, we significantly enhance its diffraction efficiency, achieving numerical efficiencies up to 78% and Q-factors as high as 1362. Experimentally, we demonstrated efficiencies of up to 59% with a Q-factor of 93. Additionally, we applied our topology-optimized metasurface to color selectivity, producing vivid colors at 4 narrow-band wavelengths. Our investigation represents a significant advancement in metasurface technology, with potential applications in see-through optical combiners and augmented reality platforms.

LPS exacerbates TRPV4-mediated itch through the intracellular TLR4-PI3K signalling.

Pruritus is often accompanied with bacterial infections, but the underlying mechanism is not fully understood. Although previous studies revealed that lipopolysaccharides (LPS) could directly activate TRPV4 channel and TRPV4 is involved in the generation of both acute itch and chronic itch, whether and how LPS affects TRPV4-mediated itch sensation remains unclear. Here, we showed that LPS-mediated TRPV4 sensitization exacerbated GSK101-induced scratching behaviour in mice. Moreover, this effect was compromised in TLR4-knockout mice, suggesting LPS acted through a TLR4-dependent mechanism. Mechanistically, LPS enhanced GSK101-evoked calcium influx in mouse ear skin cells and HEK293T cells transfected with TRPV4. Further, LPS sensitized TRPV4 channel through the intracellular TLR4-PI3K-AKT signalling. In summary, our study found a modulatory role of LPS in TRPV4 function and highlighted the TLR4-TRPV4 interaction in itch signal amplification.

HDGF stimulates liver tumorigenesis by enhancing reactive oxygen species generation in mitochondria.

Hepatoma-derived growth factor (HDGF) overexpression and uncontrolled reactive oxygen species (ROS) accumulation are involved in malignant transformation and poor prognosis in various types of cancer. However, the interplay between HDGF and ROS generation has not been elucidated in hepatocellular carcinoma. Here, we first analyzed the profile of HDGF expression and ROS production in newly generated orthotopic hepatomas by ultrasound-guided implantation. In situ superoxide detection showed that HDGF-overexpressing hepatomas had significantly elevated ROS levels compared with adjacent nontumor tissues. Consistently, liver tissues from HDGF-deficient mice exhibited lower ROS fluorescence than those from age- and sex-matched WT mice. ROS-detecting fluorescent dyes and flow cytometry revealed that recombinant HDGF (rHDGF) stimulated the production of superoxide anion, hydrogen peroxide, and mitochondrial ROS generation in cultured hepatoma cells in a dose-dependent manner. In contrast, the inactive Ser103Ala rHDGF mutant failed to promote ROS generation or oncogenic behaviors. Seahorse metabolic flux assays revealed that rHDGF dose dependently upregulated bioenergetics through enhanced basal and total oxygen consumption rate, extracellular acidification rate, and oxidative phosphorylation in hepatoma cells. Moreover, antioxidants of N-acetyl cysteine and MitoQ treatment significantly inhibited HDGF-mediated cell proliferation and invasive capacity. Genetic silencing of superoxide dismutase 2 augmented the HDGF-induced ROS generation and oncogenic behaviors of hepatoma cells. Finally, genetic knockdown nucleolin (NCL) and antibody neutralization of surface NCL, the HDGF receptor, abolished the HDGF-induced increase in ROS and mitochondrial energetics. In conclusion, this study has demonstrated for the first time that the HDGF/NCL signaling axis induces ROS generation by elevating ROS generation in mitochondria, thereby stimulating liver carcinogenesis.

Disease control outcomes of stereotactic body radiation therapy or moderate hypo-fractionation for prostate cancer: Real-world experience at two Canadian centers.

BACKGROUND: Advantages of using stereotactic body radiation therapy to treat prostate cancer include short treatment times, decreased costs, and limited toxicity. Randomized trial outcomes comparing 5-fraction stereotactic body radiation therapy to conventionally fractionated radiotherapy or hypo-fractionated radiation therapy are pending. OBJECTIVE: We report the 10-year experience with 5-fraction stereotactic body radiation therapy and hypo-fractionated radiation therapy at two Canadian centers. MATERIAL AND METHODS: Patients with low- or intermediate-risk prostate cancer treated with stereotactic body radiation therapy alone (35-40 Gy in 5 fractions) or hypo-fractionated radiation therapy alone (60-62 Gy in 20 fractions) in the period of July 2010 and June 2020. The biochemical relapse-free survival, PSA nadir, interval time to PSA nadir, time to biochemical recurrence (2 ng/ml above PSA nadir) and overall survival were reviewed. Outcomes between treatment groups were compared after propensity-matching by patient baseline characteristics. Kaplan-Meier curves were used to assess biochemical relapse-free survival and overall survival. RESULTS: We identified 205 and 513 patients with low or intermediate-risk prostate cancer who were treated with stereotactic body radiation therapy or hypo-fractionation, respectively. Intermediate-risk category composed 81% and 95% of the stereotactic body radiation therapy and hypo-fractionated radiation therapy cohorts, respectively. After a median follow up of 58.6 months for the stereotactic body radiation therapy cohort and 45.0 months for the hypo-fractionated cohort, biochemical relapse-free survival and overall survival were not significantly different between treatment groups. The 5-year biochemical relapse-free survival rates were 92.1% and 93.6% and overall survival rates were 96.4% and 95.0% for the stereotactic body radiation therapy and hypo-fractionated cohorts, respectively, after propensity-matching. Stereotactic body radiation therapy resulted in a significantly lower PSA nadir (0.18 ng/ml) compared to hypo-fractionated radiation therapy (0.48 ng/ml) in patients with low-risk prostate cancer. Mean time to biochemical recurrence was not different between treatment groups. CONCLUSIONS: Stereotactic body radiation therapy is an effective treatment option for low and intermediate-risk prostate cancer with encouraging biochemical relapse-free survival and overall survival rates comparable with hypo-fractionated radiation therapy.

The implication of serum HLA-G in angiogenesis of multiple myeloma.

BACKGROUND: Despite the advances of therapies, multiple myeloma (MM) remains an incurable hematological cancer that most patients experience relapse. Tumor angiogenesis is strongly correlated with cancer relapse. Human leukocyte antigen G (HLA-G) has been known as a molecule to suppress angiogenesis. We aimed to investigate whether soluble HLA-G (sHLA-G) was involved in the relapse of MM. METHODS: We first investigated the dynamics of serum sHLA-G, vascular endothelial growth factor (VEGF) and interleukin 6 (IL-6) in 57 successfully treated MM patients undergoing remission and relapse. The interactions among these angiogenesis-related targets (sHLA-G, VEGF and IL-6) were examined in vitro. Their expression at different oxygen concentrations was investigated using a xenograft animal model by intra-bone marrow and skin grafts with myeloma cells. RESULTS: We found that HLA-G protein degradation augmented angiogenesis. Soluble HLA-G directly inhibited vasculature formation in vitro. Mechanistically, HLA-G expression was regulated by hypoxia-inducible factor-1α (HIF-1α) in MM cells under hypoxia. We thus developed two mouse models of myeloma xenografts in intra-bone marrow (BM) and underneath the skin, and found a strong correlation between HLA-G and HIF-1α expressions in hypoxic BM, but not in oxygenated tissues. Yet when stimulated with IL-6, both HLA-G and HIF-1α could be targeted to ubiquitin-mediated degradation via PARKIN. CONCLUSION: These results highlight the importance of sHLA-G in angiogenesis at different phases of multiple myeloma. The experimental evidence that sHLA-G as an angiogenesis suppressor in MM may be useful for future development of novel therapies to prevent relapse.

PD-L1-positive circulating endothelial progenitor cells associated with immune response to PD-1 blockade in patients with head and neck squamous cell carcinoma.

A number of the inhibitors against programmed death protein 1 (PD-1) have been approved to treat recurrent or metastatic squamous cell carcinoma of head and neck (HNSCC). The interaction between PD-1 and its ligand (PD-L1) serves as an immune checkpoint that governs cytotoxic immune effectors against tumors. Numerous clinical trials of PD-1/PD-L1 inhibitors have so far been discordant about having sufficient PD-L1 expression in the tumor as a prerequisite for a successful anti-PD-1 treatment. On the other hand, vascular endothelial cells modulate immune activities through PD-L1 expression, and thus it is possible that the expressions of circulating endothelial cells (CECs) and circulating endothelial progenitor cells (CPCs) could affect antitumor immunity as well as neoangiogenesis. Here we investigated the potential involvement of PD-L1+ CECs and PD-L1+ CPCs in PD-1 blockade treatments for HNSCC patients. We measured CD8+ T cells, CECs, and CPCs in the peripheral blood of the HNSCC patients treated by anti-PD-1 therapies. We found that their PD-L1+ CPC expression before anti-PD1 therapies was strongly correlated with treatment responses and overall survival. Moreover, if the first infusion of PD-1 inhibitors reduced ≥ 50% PD-L1+ CPCs, a significantly better outcome could be predicted. In these patients as well as in an animal model of oral cancer, Pd-l1+ CPC expression was associated with limited CD8+ T-cell infiltration into the tumors, and anti-PD-1 treatments also targeted Pd-l1+ CPCs and increased CD8+ T-cell infiltration. Our results highlight PD-L1+ CPC as a potential regulator in the anti-PD-1 treatments for HNSCC.