Tissue regulatory T cells.

Foxp3+  CD4+ regulatory T cells (Tregs) are an immune cell lineage endowed with immunosuppressive functionality in a wide array of contexts, including both anti-pathogenic and anti-self responses. In the past decades, our understanding of the functional diversity of circulating or lymphoid Tregs has grown exponentially. Only recently, the importance of Tregs residing within non-lymphoid tissues, such as visceral adipose tissue, muscle, skin and intestine, has been recognized. Not only are Tregs critical for influencing the kinetics and strength of immune responses, but the regulation of non-immune or parenchymal cells, also fall within the purview of tissue-resident or infiltrating Tregs. This review focuses on providing a systematic and comprehensive comparison of the molecular maintenance, local adaptation and functional specializations of Treg populations operating within different tissues.

A matter of when, not whether: A meta-analysis of modesty bias in East Asian self-ratings of job performance.

Much attention has been paid to the question of whether there is a modesty bias in East Asian employees' self-ratings of job performance (i.e., a tendency to self-rate their performance lower than supervisors rate it). However, empirical results are conflicting, with some studies supporting the modesty bias and others not supporting it. We suggest that moderators representing boundary conditions for the modesty bias effect may shed light on these conflicting results. In essence, the question should not be "whether there is a modesty bias," but rather "when is there a modesty bias?" We propose three moderators: purpose of the ratings (administrative, developmental, or research), job performance dimension (task performance, organizational citizenship behavior, or leadership), and country-level in-group collectivism. Based on 40 studies (63 independent samples) with samples from East Asia (mainland China, Japan, South Korea, and Taiwan), we found no evidence of a modesty bias. That is, East Asian employees' self-ratings were, on average, higher than supervisor-ratings of job performance (i.e., a leniency bias). The one exception was when ratings were collected for research purposes; in this case, there was, on average, no mean difference between self- and supervisor-ratings. Thus, East Asian employees' research-purpose self-ratings are more modest, but this does not cross into a "modesty bias." In all, our results do not support a modesty bias as a widespread cultural norm among East Asian employees. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Too good to be true? Are supervisor-perspective ratings a valid substitute for actual supervisor ratings?

Due to well-known problems with self-ratings of job performance (e.g., inflation, weak correlation with supervisor ratings) and the challenges of collecting supervisor ratings of job performance, researchers sometimes use supervisor-perspective ratings (e.g., "how do you think your supervisor would rate your job performance?") instead. The assumption is supervisor-perspective ratings are less affected by the noted issues with self-ratings and therefore are more similar to actual supervisor ratings than traditional self-ratings. In fact, a considerable number of researchers have used supervisor-perspective ratings as an alternative to actual supervisor ratings. The purpose of this study is to meta-analytically determine the degree to which supervisor-perspective ratings are a valid substitute for actual supervisor ratings and identify the boundary conditions for this substitution. Our meta-analyses demonstrate that supervisor-perspective ratings are generally not a viable substitute for actual supervisor ratings. This is especially the case when (a) citizenship performance is measured, (b) data are collected in collectivistic cultures, and (c) all study data are gathered from the same source. We recommend not using supervisor-perspective ratings as a substitute for actual supervisor ratings. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Role of distinct fibroblast lineages and immune cells in dermal repair following UV radiation-induced tissue damage.

Solar ultraviolet radiation (UVR) is a major source of skin damage, resulting in inflammation, premature ageing, and cancer. While several UVR-induced changes, including extracellular matrix reorganisation and epidermal DNA damage, have been documented, the role of different fibroblast lineages and their communication with immune cells has not been explored. We show that acute and chronic UVR exposure led to selective loss of fibroblasts from the upper dermis in human and mouse skin. Lineage tracing and in vivo live imaging revealed that repair following acute UVR is predominantly mediated by papillary fibroblast proliferation and fibroblast reorganisation occurs with minimal migration. In contrast, chronic UVR exposure led to a permanent loss of papillary fibroblasts, with expansion of fibroblast membrane protrusions partially compensating for the reduction in cell number. Although UVR strongly activated Wnt signalling in skin, stimulation of fibroblast proliferation by epidermal ß-catenin stabilisation did not enhance papillary dermis repair. Acute UVR triggered an infiltrate of neutrophils and T cell subpopulations and increased pro-inflammatory prostaglandin signalling in skin. Depletion of CD4- and CD8-positive cells resulted in increased papillary fibroblast depletion, which correlated with an increase in DNA damage, pro-inflammatory prostaglandins, and reduction in fibroblast proliferation. Conversely, topical COX-2 inhibition prevented fibroblast depletion and neutrophil infiltration after UVR. We conclude that loss of papillary fibroblasts is primarily induced by a deregulated inflammatory response, with infiltrating T cells supporting fibroblast survival upon UVR-induced environmental stress.

Treg regulation of the epithelial stem cell lineage.

Tissue repair and maintenance in adult organisms is dependent on the interactions between stem cells (SCs) and constituent cells of their microenvironment, or niche. Accumulating evidence suggests that immune cells, specifically Foxp3+ CD4+ Regulatory T cells (Tregs), play an important role as a regulator of the SC niche. Undisputedly, Tregs are the major immunosuppressive lineage of the CD4+ T cell compartment, and reside within numerous secondary lymphoid organs, where they exert their functions. These cells are also specialised in facilitating protective functions specific to their tissue of residence. In this review, we discuss the emerging concepts supporting the SC-regulatory functions of tissue-resident Tregs, during both the steady-state and SC-mediated regeneration. We highlight the skin, intestines, and lung as model organs which are subject to recurrent microinjury,exposure to microbiota, and constantly replenished by resident stem cell populations. An in-depth understanding of the biology of the Treg-SC axis will inform ongoing immunotherapeutic endeavours to target specific subpopulations of tissue-resident Tregs.

Mechanisms, Hallmarks, and Implications of Stem Cell Quiescence.

Cellular quiescence is a dormant but reversible cellular state in which cell-cycle entry and proliferation are prevented. Recent studies both in vivo and in vitro demonstrate that quiescence is actively maintained through synergistic interactions between intrinsic and extrinsic signals. Subtypes of adult mammalian stem cells can be maintained in this poised, quiescent state, and subsequently reactivated upon tissue injury to restore homeostasis. However, quiescence can become deregulated in pathological settings. In this review, we discuss the recent advances uncovering intracellular signaling pathways, transcriptional changes, and extracellular cues within the stem cell niche that control induction and exit from quiescence in tissue stem cells. We discuss the implications of quiescence as well as the pharmacological and genetic approaches that are being explored to either induce or prevent quiescence as a therapeutic strategy.

Red vs. green: Does the exam booklet color matter in higher education summative evaluations? Not likely.

We examined the so-called "red effect" in the context of higher education summative exams under the premise that unlike the conditions or situations where this effect typically has been obtained, the totality of factors, such as higher motivation, familiarity with exam material, and more reliance on domain knowledge that characterize high-stakes testing such as those in operational educational settings, are likely to mitigate any color effects. Using three naturally occurring archival data sets in which students took exams on either red or green exam booklets, the results indicated that booklet color (red vs. green) did not affect exam performance. From a scientific perspective, the results suggest that color effects may be attenuated by factors that characterize high-stakes assessments, and from an applied perspective, they suggest that the choice of red vs. green exam booklets in higher education summative evaluations is likely not a concern.

Roles of Cross-Membrane Transport and Signaling in the Maintenance of Cellular Homeostasis.

Organelles allow specialized functions within cells to be localized, contained and independently regulated. This separation is oftentimes achieved by selectively permeable membranes, which enable control of molecular transport, signaling between compartments and containment of stress-inducing factors. Here we consider the role of a number of membrane systems within the cell: the plasma membrane, that of the endoplasmic reticulum, and then focusing on the nucleus, depository for chromatin and regulatory centre of the cell. Nuclear pores allow shuttling of ions, metabolites, proteins and mRNA to and from the nucleus. The activity of transcription factors and signaling molecules is also modulated by translocation across the nuclear envelope. Many of these processes require 'active transportation' against a concentration gradient and may be regulated by the nuclear pores, Ran-GTP activity and the nuclear lamina. Cells must respond to a combination of biochemical and physical inputs and we discuss too how mechanical signals are carried from outside the cell into the nucleus through integrins, the cytoskeleton and the 'linker of nucleo- and cyto-skeletal' (LINC) complex which spans the nuclear envelope. Regulation and response to signals and stresses, both internal and external, allow cells to maintain homeostasis within functional tissue.