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Emotions and individual differences shape human foraging under threat
A common behavior in natural environments is foraging for rewards. However, this is often in the presence of predators. Therefore, one of the most fundamental decisions for humans, as for other animals, is how to apportion time between reward-motivated pursuit behavior and threat-motivated checking behavior. To understand what affects how people strike this balance, we developed an ecologically inspired task and looked at both within-participant dynamics (moods) and between-participant individual differences (questionnaires about real-life behaviors) in two large internet samples (n = 374 and n = 702) in a cross-sectional design. For the within-participant dynamics, we found that people regulate task-evoked stress homeostatically by changing behavior (increasing foraging and hiding). Individual differences, even in superficially related traits (apathy–anhedonia and anxiety–compulsive checking) reliably mapped onto unique behaviors. Worse task performance, due to maladaptive checking, was linked to gender (women checked excessively) and specific anxiety-related traits: somatic anxiety (reduced self-reported checking due to worry) and compulsivity (self-reported disorganized checking). While anhedonia decreased self-reported task engagement, apathy, strikingly, improved overall task performance by reducing excessive checking. In summary, we provide a multifaceted paradigm for assessment of checking for threat in a naturalistic task that is sensitive to both moods as they change throughout the task and clinical dimensions. Thus, it could serve as an objective measurement tool for future clinical studies interested in threat, vigilance or behavior–emotion interactions in contexts requiring both reward seeking and threat avoidance.
Effector CD8 T cell differentiation in primary and breakthrough SARS-CoV-2 infection in mice
The nature of the effector and memory T cell response in the lungs following acute SARS-CoV-2 infections remains largely unknown. To define the pulmonary T-cell response to COVID-19, we compared effector and memory T-cell responses to SARS-CoV-2 and influenza A virus (IAV) in mice. Both viruses elicited potent effector T cell responses in lungs, but memory T cells showed exaggerated contraction in SARS-CoV-2-infected mice. Specifically, unlike the T-bet/EOMES-driven effector transcription program in IAV lungs, SARS-CoV-2-specific CD8 T cells embarked on a STAT-3-centric transcriptional program, a defining characteristic of a pro-fibro-inflammatory program: limited cytotoxicity, diminished expression of tissue-protective inhibitory receptors (PD-1, LAG-3, and TIGIT), and augmented mucosal imprinting (CD103). Circulating CD45RO+HLA-DR+ CD8 T cells in hospitalized COVID-19 patients expressed elevated levels of STAT-3 and low levels of TIGIT. IL-6 blockade experiments implicated IL-6 in STAT-3 induction and downregulation of PD-1 expression on SARS-CoV-2-specific primary effector CD8 T cells. Memory CD8 T cells specific to a single epitope, induced by mucosal vaccination, differentiated into cytotoxic effectors and expressed high levels of CD103, effectively reducing viral burden in lungs following a breakthrough SARS-CoV-2 infection. Our findings have implications for developing targeted immunotherapies to mitigate immunopathology and promote protective T cell immunity to SARS-CoV-2.
Inhibition of sympathetic tone via hypothalamic descending pathway propagates glucocorticoid-induced endothelial impairment and osteonecrosis of the femoral head
Osteonecrosis of the femoral head (ONFH) is a common complication of glucocorticoid (GC) therapy. Recent advances demonstrate that sympathetic nerves regulate bone homeostasis, and GCs lower the sympathetic tone. Here, we show that the dramatically decreased sympathetic tone is closely associated with the pathogenesis of GC-induced ONFH. GCs activate the glucocorticoid receptor (GR) but hinder the activation of the mineralocorticoid receptor (MR) on neurons in the hypothalamic paraventricular nucleus (PVN). This disrupts the balance of corticosteroid receptors (GR/MR) and subsequently reduces the sympathetic outflow in the PVN. Vascular endothelial cells rapidly react to inhibition of sympathetic tone by provoking endothelial apoptosis in adult male mice treated with methylprednisolone (MPS) daily for 3 days, and we find substantially reduced H-type vessels in the femoral heads of MPS-treated ONFH mice. Importantly, treatment with a GR inhibitor (RU486) in the PVN promotes the activation of MR and rebalances the ratio of GR and MR, thus effectively boosting sympathetic outflow, as shown by an increase in tyrosine hydroxylase expression in both the PVN and the sympathetic postganglionic neurons and an increase in norepinephrine levels in both the serum and bone marrow of the femoral head of MPS-treated mice. Rebalancing the corticosteroid receptors mitigates GC-induced endothelial impairment and ONFH and promotes angiogenesis coupled with osteogenesis in the femoral head, while these effects are abolished by chemical sympathectomy with 6-OHDA or adrenergic receptor-β2 (Adrb2) knockout. Furthermore, activating Adrb2 signaling in vivo is sufficient to rescue the GC-induced ONFH phenotype. Mechanistically, norepinephrine increases the expression of the key glycolytic gene 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) via Adrb2-cyclic AMP response element-binding protein (CREB) signaling. Endothelial-specific overexpression of PFKFB3 attenuates endothelial impairment and prevents severe osteonecrosis in MPS-treated Adrb2 knockout mice. Thus, GC inhibits sympathetic tone via the hypothalamic descending pathway, which, in turn, acts as a mediator of GC-induced ONFH.
Targeting of TAMs: can we be more clever than cancer cells?
With increasing incidence and geography, cancer is one of the leading causes of death, reduced quality of life and disability worldwide. Principal progress in the development of new anticancer therapies, in improving the efficiency of immunotherapeutic tools, and in the personification of conventional therapies needs to consider cancer-specific and patient-specific programming of innate immunity. Intratumoral TAMs and their precursors, resident macrophages and monocytes, are principal regulators of tumor progression and therapy resistance. Our review summarizes the accumulated evidence for the subpopulations of TAMs and their increasing number of biomarkers, indicating their predictive value for the clinical parameters of carcinogenesis and therapy resistance, with a focus on solid cancers of non-infectious etiology. We present the state-of-the-art knowledge about the tumor-supporting functions of TAMs at all stages of tumor progression and highlight biomarkers, recently identified by single-cell and spatial analytical methods, that discriminate between tumor-promoting and tumor-inhibiting TAMs, where both subtypes express a combination of prototype M1 and M2 genes. Our review focuses on novel mechanisms involved in the crosstalk among epigenetic, signaling, transcriptional and metabolic pathways in TAMs. Particular attention has been given to the recently identified link between cancer cell metabolism and the epigenetic programming of TAMs by histone lactylation, which can be responsible for the unlimited protumoral programming of TAMs. Finally, we explain how TAMs interfere with currently used anticancer therapeutics and summarize the most advanced data from clinical trials, which we divide into four categories: inhibition of TAM survival and differentiation, inhibition of monocyte/TAM recruitment into tumors, functional reprogramming of TAMs, and genetic enhancement of macrophages.
Type 2 immunity in allergic diseases
Significant advancements have been made in understanding the cellular and molecular mechanisms of type 2 immunity in allergic diseases such as asthma, allergic rhinitis, chronic rhinosinusitis, eosinophilic esophagitis (EoE), food and drug allergies, and atopic dermatitis (AD). Type 2 immunity has evolved to protect against parasitic diseases and toxins, plays a role in the expulsion of parasites and larvae from inner tissues to the lumen and outside the body, maintains microbe-rich skin and mucosal epithelial barriers and counterbalances the type 1 immune response and its destructive effects. During the development of a type 2 immune response, an innate immune response initiates starting from epithelial cells and innate lymphoid cells (ILCs), including dendritic cells and macrophages, and translates to adaptive T and B-cell immunity, particularly IgE antibody production. Eosinophils, mast cells and basophils have effects on effector functions. Cytokines from ILC2s and CD4+ helper type 2 (Th2) cells, CD8 + T cells, and NK-T cells, along with myeloid cells, including IL-4, IL-5, IL-9, and IL-13, initiate and sustain allergic inflammation via T cell cells, eosinophils, and ILC2s; promote IgE class switching; and open the epithelial barrier. Epithelial cell activation, alarmin release and barrier dysfunction are key in the development of not only allergic diseases but also many other systemic diseases. Recent biologics targeting the pathways and effector functions of IL4/IL13, IL-5, and IgE have shown promising results for almost all ages, although some patients with severe allergic diseases do not respond to these therapies, highlighting the unmet need for a more detailed and personalized approach.
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