In Vitro Models of Bone Marrow Remodelling and Immune Dysfunction in Space: Present State and Future Directions

Gravitational forces and matrix stiffness modulate the invasiveness of breast cancer cells in bioprinted spheroids

The progression of breast cancer is influenced by the stiffness of the extracellular matrix (ECM), which becomes stiffer as cancer advances due to increased collagen IV and laminin secretion by cancer-associated fibroblasts. Intriguingly, breast cancer cells cultivated in two-dimensions exhibit a less aggressive behavior when exposed to weightlessness, or microgravity conditions. This study aims to elucidate the interplay between matrix stiffness and microgravity on breast cancer progression. For this purpose, three-dimensional spheroids of breast cancer cell lines (MCF-7 and MDA-MB-231) were formed. These spheroids were subsequently bioprinted in hydrogels of varying stiffness, obtained by the mixing of gelatin methacrylate and poly(ethylene) glycol diacrylate mixed at different ratios. The constructs were printed with a custom stereolithography (SLA) bioprinter converted from a low-cost, commercially available 3D printer. These bioprinted structures, encapsulating breast cancer spheroids, were then placed in a clinostat (microgravity simulation device) for a duration of seven days. Comparative analyses were conducted between objects cultured under microgravity and standard earth gravity conditions. Protein expression was characterized through fluorescent microscopy, while gene expression of MCF-7 constructs was analyzed via RNA sequencing. Remarkably, the influence of a stiffer ECM on the protein and gene expression levels of breast cancer cells could be modulated and sometimes even reversed in microgravity conditions. The study's findings hold implications for refining therapeutic strategies for advanced breast cancer stages - an array of genes involved in reversing aggressive or even metastatic behavior might lead to the discovery of new compounds that could be used in a clinical setting.

Thymus ad astra, or spaceflight-induced thymic involution

Spaceflight imposes a constellation of physiological challenges-cosmic radiation, microgravity, disrupted circadian rhythms, and psychosocial stress-that critically compromise astronaut health. Among the most vulnerable organs is the thymus, a cornerstone of immune system functionality, tasked with generating naive T cells essential for adaptive immunity. The thymus is particularly sensitive to spaceflight conditions, as its role in maintaining immune homeostasis is tightly regulated by a balance of systemic and local factors easily disrupted in space. Cosmic radiation, an omnipresent hazard beyond Earth's magnetosphere, accelerates DNA damage and cellular senescence in thymic epithelial cells, impairing thymopoiesis and increasing the risk of immune dysregulation. Microgravity and circadian rhythm disruption exacerbate this by altering immune cell migration patterns and stromal support, critical for T-cell development. Psychosocial stressors, including prolonged isolation and mission-induced anxiety, further compound thymic atrophy by elevating systemic glucocorticoid levels. Ground-based analogs simulating cosmic radiation and microgravity have been instrumental in elucidating mechanisms of thymic involution and its downstream effects on immunity. These models reveal that long-duration missions result in diminished naive T-cell output, leaving astronauts vulnerable to infections and possibly at high risk for developing neoplasia. Advances in countermeasures, such as pharmacological interventions targeting thymic regeneration and bioengineering approaches to protect thymic architecture, are emerging as vital strategies to preserve immune resilience during prolonged space exploration. Focusing on the thymus as a central hub of immune vulnerability underscores its pivotal role in spaceflight-induced health risks. Understanding these dynamics will not only enhance the safety of human space missions but also provide critical insights into thymus biology under extreme conditions.

Changing the gravity vector direction by inverted culture enhances radiation-induced cell damage

In recent years, it has become clear that the cytotoxicity of γ-irradiation of cells is increased under microgravity conditions. However, there has been no study of the effect of the gravity vector direction, rather than the magnitude, on γ-ray-induced cytotoxicity. Therefore, in this study, we inverted cultures of human bronchial epithelium BEAS-2B cells and human lung cancer A549 cells in order to change the gravity vector direction by 180° with respect to the cells and observed the cellular response to radiation in this state. We found that cells in inverted culture showed increased irradiation-induced production of reactive oxygen species and decreased expression of the antioxidant protein thioredoxin-1 compared to cells in normal culture. Furthermore, the DNA damage response was delayed in γ-irradiated cells in inverted culture, and the number of unrepaired DNA sites was increased, compared to irradiated cells in normal culture. γ-Ray-induced cell death and the number of G2-M arrested cells were increased in inverted culture, in accordance with the decreased capacity for DNA repair. Our findings suggest that the gravity vector direction, as well as its magnitude, alters the cellular response to radiation.

Hematopoietic aging: Cellular, molecular, and related mechanisms

ABSTRACT

Aging is accompanied by significant inhibition of hematopoietic and immune system function and disruption of bone marrow structure. Aging-related alterations in the inflammatory response, immunity, and stem cell niches are at the root of hematopoietic aging. Understanding the molecular mechanisms underlying hematopoietic and bone marrow aging can aid the clinical treatment of aging-related diseases. In particular, it is unknown how the niche reprograms hematopoietic stem cells (HSCs) in an age-dependent manner to maintain normal hematopoiesis in elderly individuals. Recently, specific inhibitors and blood exchange methods have been shown to reshape the hematopoietic niche and reverse hematopoietic aging. Here, we present the latest scientific discoveries related to hematopoietic aging and hematopoietic system rejuvenation, discuss the relationships between hematopoietic niche aging and HSC aging, and describe related studies on stem cell-mediated regulation of hematopoietic aging, aiming to provide new ideas for further study.

How do gravity alterations affect animal and human systems at a cellular/tissue level?

The present white paper concerns the indications and recommendations of the SciSpacE Science Community to make progress in filling the gaps of knowledge that prevent us from answering the question: "How Do Gravity Alterations Affect Animal and Human Systems at a Cellular/Tissue Level?" This is one of the five major scientific issues of the ESA roadmap "Biology in Space and Analogue Environments". Despite the many studies conducted so far on spaceflight adaptation mechanisms and related pathophysiological alterations observed in astronauts, we are not yet able to elaborate a synthetic integrated model of the many changes occurring at different system and functional levels. Consequently, it is difficult to develop credible models for predicting long-term consequences of human adaptation to the space environment, as well as to implement medical support plans for long-term missions and a strategy for preventing the possible health risks due to prolonged exposure to spaceflight beyond the low Earth orbit (LEO). The research activities suggested by the scientific community have the aim to overcome these problems by striving to connect biological and physiological aspects in a more holistic view of space adaptation effects.

The Impact of Microgravity on Immunological States

As we explore other planetary bodies, astronauts will face unique environmental and physiological challenges. The human immune system has evolved under Earth's gravitational force. Consequently, in the microgravity environment of space, immune function is altered. This can pose problematic consequences for astronauts on deep space missions where medical intervention will be limited. Studying the unique environment of microgravity has its challenges, yet current research has uncovered immunological states that are probable during exploration missions. As microgravity-induced immune states are uncovered, novel countermeasure developments and personalized mitigation programs can be designed to improve astronaut health. This can also benefit immune-related monitoring programs for disorders on Earth. This is a comprehensive review, including gaps in knowledge, of simulated and spaceflight microgravity studies in human and rodent models.

Bio-Inspired Nanomaterials for Micro/Nanodevices: A New Era in Biomedical Applications

Exploring bio-inspired nanomaterials (BINMs) and incorporating them into micro/nanodevices represent a significant development in biomedical applications. Nanomaterials, engineered to imitate biological structures and processes, exhibit distinctive attributes such as exceptional biocompatibility, multifunctionality, and unparalleled versatility. The utilization of BINMs demonstrates significant potential in diverse domains of biomedical micro/nanodevices, encompassing biosensors, targeted drug delivery systems, and advanced tissue engineering constructs. This article thoroughly examines the development and distinctive attributes of various BINMs, including those originating from proteins, DNA, and biomimetic polymers. Significant attention is directed toward incorporating these entities into micro/nanodevices and the subsequent biomedical ramifications that arise. This review explores biomimicry's structure-function correlations. Synthesis mosaics include bioprocesses, biomolecules, and natural structures. These nanomaterials' interfaces use biomimetic functionalization and geometric adaptations, transforming drug delivery, nanobiosensing, bio-inspired organ-on-chip systems, cancer-on-chip models, wound healing dressing mats, and antimicrobial surfaces. It provides an in-depth analysis of the existing challenges and proposes prospective strategies to improve the efficiency, performance, and reliability of these devices. Furthermore, this study offers a forward-thinking viewpoint highlighting potential avenues for future exploration and advancement. The objective is to effectively utilize and maximize the application of BINMs in the progression of biomedical micro/nanodevices, thereby propelling this rapidly developing field toward its promising future.

Insights into the relationship between persistent antibody secretion and metabolic programming - A question for single-cell analysis

Vaccination aims to generate a protective and persisting antibody response. Indeed, humoral vaccine-mediated protection depends on the quality and quantity of the produced antigen-specific antibodies for its initial magnitude and the persistence of the plasma cells for its duration. Therefore, understanding the mechanisms behind the generation, selection and maintenance of long-lived plasma cells secreting protective antibodies is of fundamental importance for understanding long-term immunity, vaccine responses, therapeutical approaches for autoimmune disease and multiple myeloma. Recent studies have observed correlations between the generation, function and lifespan of plasma cells and their metabolism, with metabolism being both a main driver and primary consequence of changes in cellular behavior. This review introduces how metabolic programs influence and drive immune cell functions in general and plasma cell differentiation and longevity more specifically, summarizing the current knowledge on metabolic pathways and their influences on cellular fate. In addition, available technologies to profile metabolism and their limitations are discussed, leading to the unique and open technological challenges for further advancement of this research field.

Extraterrestrial Gynecology: Could Spaceflight Increase the Risk of Developing Cancer in Female Astronauts? An Updated Review

Outer space is an extremely hostile environment for human life, with ionizing radiation from galactic cosmic rays and microgravity posing the most significant hazards to the health of astronauts. Spaceflight has also been shown to have an impact on established cancer hallmarks, possibly increasing carcinogenic risk. Terrestrially, women have a higher incidence of radiation-induced cancers, largely driven by lung, thyroid, breast, and ovarian cancers, and therefore, historically, they have been permitted to spend significantly less time in space than men. In the present review, we focus on the effects of microgravity and radiation on the female reproductive system, particularly gynecological cancer. The aim is to provide a summary of the research that has been carried out related to the risk of gynecological cancer, highlighting what further studies are needed to pave the way for safer exploration class missions, as well as postflight screening and management of women astronauts following long-duration spaceflight.

Microgravity and Space Medicine 2.0

This Special Issue (SI), "Microgravity and Space Medicine 2 [...].