Parsing a plethora of pollen: the role of pollen size and shape in the evolution of Boraginaceae.

Pollen, the microgametophyte of seed plants, has an important role in plant reproduction and, therefore, evolution. Pollen is variable in, for example, size, shape, aperture number; these features are particularly diverse in some plant taxa and can be diagnostic. In one family, Boraginaceae, the range of pollen diversity suggests the potential utility of this family as a model for integrative studies of pollen development, evolution and molecular biology. In the present study, a comprehensive survey of the diversity and evolution of pollen from 538 species belonging to 72 genera was made using data from the literature and additional scanning electron microscopy examination. Shifts in diversification rates and the evolution of various quantitative characters were detected, and the results revealed remarkable differences in size, shape and number of apertures. The pollen of one subfamily, Boraginoideae, is larger than that in Cynoglossoideae. The diversity of pollen shapes and aperture numbers in one tribe, Lithospermeae, is greater than that in the other tribes. Ancestral pollen for the family was resolved as small, prolate grains that bear three apertures and are iso-aperturate. Of all the tribes, the greatest number of changes in pollen size and aperture number were observed in Lithospermeae and Boragineae, and the number of apertures was found to be stable throughout all tribes of Cynoglossoideae. In addition, the present study showed that diversification of Boraginaceae cannot be assigned to a single factor, such as pollen size, and the increased rate of diversification for species-rich groups (e.g. Cynoglossum) is not correlated with pollen size or shape evolution. The palynological data and patterns of character evolution presented in the study provide better resolution of the roles of geographical and ecological factors in the diversity and evolution of pollen grains of Boraginaceae, and provide suggestions for future palynological research across the family.

Targeting TRIM29 As a Negative Regulator of CAR-NK Cell Effector Function to Improve Antitumor Efficacy of These Cells: A Perspective.

Natural killer (NK) cells are among the most important cells in innate immune defense. In contrast to T cells, the effector function of NK cells does not require prior stimulation and is not MHC restricted. Therefore, chimeric antigen receptor (CAR)-NK cells are superior to CAR-T cells. The complexity of the tumor microenvironment (TME) makes it necessary to explore various pathways involved in NK cell negative regulation. CAR-NK cell effector function can be improved by inhibiting the negative regulatory mechanisms. In this respect, the E3 ubiquitin ligase tripartite motif containing 29 (TRIM29) is known to be involved in reducing NK cell cytotoxicity and cytokine production. Also, targeting TRIM29 may enhance the antitumor efficacy of CAR-NK cells. The present study discusses the negative effects of TRIM29 on NK cell activity and genomic deletion or suppression of the expression of TRIM29 as a novel approach to optimize CAR-NK cell-based immunotherapy.

Immune responses in mildly versus critically ill COVID-19 patients.

The current coronavirus pandemic (COVID-19), caused by SARS-CoV-2, has had devastating effects on the global health and economic system. The cellular and molecular mediators of both the innate and adaptive immune systems are critical in controlling SARS-CoV-2 infections. However, dysregulated inflammatory responses and imbalanced adaptive immunity may contribute to tissue destruction and pathogenesis of the disease. Important mechanisms in severe forms of COVID-19 include overproduction of inflammatory cytokines, impairment of type I IFN response, overactivation of neutrophils and macrophages, decreased frequencies of DC cells, NK cells and ILCs, complement activation, lymphopenia, Th1 and Treg hypoactivation, Th2 and Th17 hyperactivation, as well as decreased clonal diversity and dysregulated B lymphocyte function. Given the relationship between disease severity and an imbalanced immune system, scientists have been led to manipulate the immune system as a therapeutic approach. For example, anti-cytokine, cell, and IVIG therapies have received attention in the treatment of severe COVID-19. In this review, the role of immunity in the development and progression of COVID-19 is discussed, focusing on molecular and cellular aspects of the immune system in mild vs. severe forms of the disease. Moreover, some immune- based therapeutic approaches to COVID-19 are being investigated. Understanding key processes involved in the disease progression is critical in developing therapeutic agents and optimizing related strategies.