Biology subjects

Kubes, P.

Publications and source records attributed to Kubes, P..

7 recordsLinked to original sources

bioRxiv2026

Pre-existing Th1 immunity is abrogated by ongoing recruitment of monocytic host cells that are refractory to activation

Protective immunity against many infectious diseases develops following primary infection, called infection induced immunity (III), and provides a blueprint for vaccination. However, many vaccination strategies have failed. In the parasitic Leishmania major model of self-healing cutaneous disease, control of secondary challenge infection relies on pre-existing T helper (Th)1-dependent activation of skin-infiltrating monocytes for elimination of intracellular parasites. To better understand immune-evasion of pre-existing Th1 immunity by pathogens, we investigated the pathogen-niche established following non-healing challenge infection with the L. amazonensis parasite in a setting of pre-existing III. Following secondary challenge, pre-existing Th1 III initially controlled infection but ultimately failed. Loss of protection was not overtly STAT6- or IL-10-mediated. Rather, monocyte-lineage tracing revealed inflammatory monocyte-derived PD-L1+PD-L2+ macrophages provide an intracellular pathogen-niche and facilitate evasion of pre-existing Th1 immunity. Anti-PD-1 immune checkpoint blockade enhanced uninfected, but not infected, monocyte-derived cell activation and depletion of monocyte-derived precursors improved parasite control. These observations suggest that evasion of pre-existing Th1 immunity in this setting is not due to a failure of the Th1 response, but rather due to infected-cell intrinsic defects in activation.

immunology↗

bioRxiv2026

Phenotypic dynamics and behaviors of neutrophils during barrier challenge

Neutrophils are intrinsically antimicrobial innate immune cells, but they have recently been observed to play diverse roles across various conditions. The concept of neutrophil heterogeneity has thus emerged, yet a fundamental understanding of the mechanisms and processes underlying neutrophil diversity in vivo is lacking. Here, we interrogated neutrophils native propensities to diversify by studying them in the setting of host defense to barrier challenge. Using both high-parameter, high throughput methods and intravital microscopy, we tracked cellular dynamics, identity, and behaviors and asked how these aligned with critical host defensive functions. We found that neutrophil diversity was underscored by both turnover and plasticity of cells within an infection site, and that environment-specific adaptation occurred rapidly upon extravasation and swarm initiation. The population-level phenotypic landscape shifted considerably through phases of inflammation initiation, peak, and resolution; and adaptation varied substantially between infections and aseptic wounds. Like mature neutrophils, immature neutrophils were capable of phenotypic adaptation in infection sites but were deficient in host defense functions. We unexpectedly identified a novel population of CD101-low, mature neutrophils, expressing elevated levels of PD-L1 and ICAM-1, that was associated with key antimicrobial effector functions and most pronounced during the neutrophil response to large or recalcitrant challenge. Our findings highlight that neutrophil specification is rapid and environment-dependent, and that specific phenotypes are linked to critical host defensive behaviors and functions in vivo.

immunology↗

bioRxiv2024

Mitochondrial transplantation: a novel therapy for liver ischemia/reperfusion injury

MINI-ABSTRACTMitochondrial transplantation prevented liver ischemia/reperfusion-induced hepatocellular injury and inflammation. In vivo intravital microscopy demonstrated that liver resident macrophages, namely Kupffer cells, rapidly sequestered, internalized and acidified transplanted mitochondria through the CRIg immunoreceptor. Mechanistically, both Kupffer cells and CRIg were necessary for the hepatoprotective and anti-inflammatory effects of mitochondrial transplantation. STRUCTURED ABSTRACTO_ST_ABSObjectiveC_ST_ABSTo investigate the hepatoprotective effects of mitochondrial transplantation in a murine liver ischemia/reperfusion (I/R) model. Summary background dataSequential liver ischemia followed by reperfusion (I/R) is a pathophysiological process underlying hepatocellular injury in a number of clinical contexts, such as hemorrhagic shock/resuscitation, major elective liver surgery and organ transplantation. A unifying pathogenic consequence of I/R is mitochondrial dysfunction. Restoration of mitochondria via transplantation (MTx) has emerged as potential therapeutic in I/R. However, its role in liver I/R and its mechanisms of action remain poorly defined. MethodsWe investigated the hepatoprotective effects of MTx in an in vivo mouse model of liver I/R and used in vivo imaging and various knockout and transgenic mouse models to determine the mechanism of protection. ResultsWe found that I/R-induced hepatocellular injury was prevented by MTx, as measured by plasma ALT, AST and liver histology. Additionally, I/R-induced pro-inflammatory cytokine release (IL-6, TNF) was dampened by MTx, and anti-inflammatory IL-10 was enhanced. Moreover, MTx lowered neutrophil infiltration into both the liver sinusoids and lung BALF, suggesting a local and distant reduction in inflammation. Using in vivo intravital imaging, we found that I/R-subjected Kupffer cells (KCs), rapidly sequestered transplanted mitochondria, and acidified mitochondria within lysosomal compartments. To specifically interrogate the role of KCs, we depleted KCs using the diphtheria toxin-inducible Clec4f/iDTR transgenic mouse, then induced I/R, and discovered that KCs are necessary for the beneficial effects of MTx. Finally, we induced I/R in complement receptor of the immunoglobulin superfamily (CRIg) knockout mice and found that CRIg was required for mitochondria capture by KCs and mitochondrial-mediated hepatoprotection. ConclusionsIn this study, we demonstrated that CRIg-dependent capture of mitochondria by I/R-subjected Kupffer cells is a hepatoprotective mechanism in vivo. These data progress knowledge on the mechanisms of MTx and opens new avenues for clinical translation.

cell biology↗

bioRxiv2023

P-Selectin promotes SARS-CoV-2 interactions with platelets and the endothelium

COVID-19 causes a clinical spectrum of acute and chronic illness and host / virus interactions are not completely understood1,2. To identify host factors that can influence SARS-CoV-2 infection, we screened the human genome for genes that, when upregulated, alter the outcome of authentic SARS-CoV-2 infection. From this, we identify 34 new genes that can alter the course of infection, including the innate immune receptor P-selectin, which we show is a novel SARS-CoV-2 spike receptor. At the cellular level expression of P-selectin does not confer tropism for SARS-CoV-2, instead it acts to suppress infection. More broadly, P-selectin can also promote binding to SARS-CoV-2 variants, SARS-CoV-1 and MERS, acting as a general spike receptor for highly pathogenic coronaviruses. P-selectin is expressed on platelets and endothelium3, and we confirm SARS-CoV-2 spike interactions with these cells are P-selectin-dependent and can occur under shear flow conditions. In vivo, authentic SARS-CoV-2 uses P-selectin to home to airway capillary beds where the virus interacts with the endothelium and platelets, and blocking this interaction can clear vascular-associated SARS-CoV-2 from the lung. Together we show for the first time that coronaviruses can use the leukocyte recruitment system to control tissue localization, and this fundamental insight may help us understand and control highly pathogenic coronavirus disease progression.

immunology↗

bioRxiv2023

PNAG exopolysaccharide eradication gives neutrophils access to Staphylococcus aureus biofilm infections

Staphylococcus aureus (S. aureus) can form biofilms on biotic or abiotic surfaces making biofilm infections a relevant clinical problem. Biofilms can evade immunity and resist antimicrobial treatment, and as such an understanding of biofilm infection in vivo is necessary to inform new therapeutics. Using a mouse model of S. aureus foreign-body skin infection and intravital microscopy, we imaged the interactions between neutrophils and S. aureus biofilm. We observed that neutrophils were separated from bacteria by a biofilm matrix composed of the polysaccharide intercellular adhesin (PIA), an exopolysaccharide chemically designated as poly-N-acetylglucosamine (PNAG) that is produced by enzymatic machinery encoded by the icaADBC operon. Infection with icaADBC-deficient S. aureus strains led to increased neutrophil infiltration and access to bacteria and resulted in full clearance of infection by 7 days. Moreover, enzymatic treatment with PgaB, which hydrolyzes partially deacetylated PNAG, was shown to disaggregate the biofilm giving neutrophils access into the infection site to improve clearance. Taken together, our results show that PNAG shelters S. aureus biofilms from innate host defense, and that targeting the biofilm matrix with glycoside hydrolases is a promising therapeutic avenue to treat S. aureus biofilm infections. Author SummaryStaphylococcus aureus is a major cause of biofilm-associated infections, which pose a major threat to human health. A biofilm is difficult to treat since bacteria are protected from antimicrobials within an extracellular matrix. This study is the first to show that the PgaB enzyme, a glycoside hydrolase, can disrupt the S. aureus biofilm matrix in vivo. Disrupting the biofilm matrix with PgaB gives neutrophils access to bacteria for elimination.

immunology↗

bioRxiv2020

Neutrophils Mediate Kidney Inflammation Following Acute Skin Exposure to UVB Light

Photosensitivity to ultraviolet (UV) light affects up to ~80% of lupus patients and can exacerbate local skin disease as well as systemic disease, including lupus nephritis. While neutrophils have been implicated in local tissue injury in lupus in response to immune complex deposition, whether and how they play a role in photosensitivity induced systemic disease is unknown. Here, we show that following skin exposure to UV light, neutrophils migrate not only to the skin, but also to the kidney, in an IL-17A-dependent manner. Kidney infiltrating neutrophils produced reactive oxygen species and their presence was associated with upregulation of endothelial adhesion molecules and inflammatory cytokines as well as the induction of kidney injury markers, including transient proteinuria. Neutrophils were responsible for inflammation and renal injury as demonstrated by experiments that inhibited neutrophil mobilization. Exploiting a mouse model containing photoactivatable immune cells, we observed that a subset of neutrophils found in the kidney had transited through UV light-exposed skin suggesting reverse transmigration. These findings demonstrate that neutrophils mediate transient kidney injury following skin exposure to UV light and, coupled with observations identifying similar neutrophil phenotypes in human lupus, could provide a mechanistic link to explain sun-induced systemic lupus flares.

immunology↗

bioRxiv2020

A molecular map of lymph node blood vascular endothelium at single cell resolution

Blood vascular endothelial cells (BECs) control the immune response by regulating immune cell recruitment, metabolite exchange and blood flow in lymphoid tissues. However, the diversity of BEC and their origins during immune angiogenesis remain poorly understood. Here we profile transcriptomes of BEC from mouse peripheral lymph nodes and map key phenotypes to the vasculature. Our analysis identifies multiple novel subsets including a venous population whose gene signature predicts an unexpectedly selective role in myeloid cell (vs lymphocyte) recruitment to the medulla, confirmed by 2 photon videomicroscopy. We define five phenotypes of capillary lining BEC including a capillary resident regenerative population (CRP) that displays stem cell and migratory gene signatures and contributes to homeostatic BEC turnover and to vascular neogenesis after immunization. Trajectory analyses reveal retention of developmental programs along a progression of cellular phenotypes from CRP to mature venous and arterial BEC subsets. Overall, our single cell atlas provides a molecular blueprint of the lymph node blood vasculature and defines subset specialization for immune cell recruitment and vascular homeostasis.

immunology↗