Immunomodulatory properties of the lymphatic endothelium in the tumor microenvironment

The tumor microenvironment (TME) is an intricate complex and dynamic structure composed of various cell types, including tumor, stromal and immune cells. Within this complex network, lymphatic endothelial cells (LECs) play a crucial role in regulating immune responses and influencing tumor progression and metastatic dissemination to lymph node and distant organs. Interestingly, LECs possess unique immunomodulatory properties that can either promote or inhibit anti-tumor immune responses. In fact, tumor-associated lymphangiogenesis can facilitate tumor cell dissemination and metastasis supporting immunoevasion, but also, different molecular mechanisms involved in LEC-mediated anti-tumor immunity have been already described. In this context, the crosstalk between cancer cells, LECs and immune cells and how this communication can shape the immune landscape in the TME is gaining increased interest in recent years. In this review, we present a comprehensive and updated report about the immunomodulatory properties of the lymphatic endothelium within the TME, with special focus on primary tumors and tumor-draining lymph nodes. Furthermore, we outline emerging research investigating the potential therapeutic strategies targeting the lymphatic endothelium to enhance anti-tumor immune responses. Understanding the intricate mechanisms involved in LEC-mediated immune modulation in the TME opens up new possibilities for the development of innovative approaches to fight cancer.

Increased sLRP1 and decreased atrial natriuretic peptide plasma levels in newly diagnosed T2DM patients are normalized after optimization of glycemic control

Background

Low-density lipoprotein receptor-related protein 1 (LRP1) negatively modulates circulating atrial natriuretic peptide (ANP) levels. Both molecules are involved in the regulation of cardiometabolism.

Objectives

To evaluate soluble LRP1 (sLRP1) and ANP levels in people with newly diagnosed type 2 diabetes mellitus (T2DM) and determine the effects of metabolic optimization.

Methods

This single-center longitudinal observational study recruited patients with newly diagnosed T2DM (n = 29, HbA1c > 8.5%), and 12 healthy control, age- and sex-matched volunteers. sLRP1 and ANP levels were measured by immunoassays at T2DM onset and at one year after optimization of glycemic control (HbA1c ≤ 6.5%).

Results

T2DM had higher sLRP1 levels than the control group (p = 0.014) and lower ANP levels (p =0.002). At 12 months, 23 T2DM patients reached the target of HbA1c ≤ 6.5%. These patients significantly reduced sLRP1 and increased ANP levels. Patients who did not achieve HbA1c < 6.5% failed to normalize sLRP1 and ANP levels. There was an inverse correlation in the changes in sLRP1 and ANP (p = 0.031). The extent of sLRP1 changes over 12 months of metabolic control positively correlated with those of total cholesterol, LDL cholesterol, TG, TG/HDLc, and apolipoprotein B.

Conclusions

Newly diagnosed T2DM patients have an increased sLRP1/ANP ratio, and increased sLRP1 and decreased ANP levels are normalized in the T2DM patients that reached an strict glycemic and metabolic control. sLRP1/ANP ratio could be a reliable marker of cardiometabolic function.

Endothelium and Subendothelial Matrix Mechanics Modulate Cancer Cell Transendothelial Migration

Cancer cell extravasation, a key step in the metastatic cascade, involves cancer cell arrest on the endothelium, transendothelial migration (TEM), followed by the invasion into the subendothelial extracellular matrix (ECM) of distant tissues. While cancer research has mostly focused on the biomechanical interactions between tumor cells (TCs) and ECM, particularly at the primary tumor site, very little is known about the mechanical properties of endothelial cells and the subendothelial ECM and how they contribute to the extravasation process. Here, an integrated experimental and theoretical framework is developed to investigate the mechanical crosstalk between TCs, endothelium and subendothelial ECM during in vitro cancer cell extravasation. It is found that cancer cell actin-rich protrusions generate complex push-pull forces to initiate and drive TEM, while transmigration success also relies on the forces generated by the endothelium. Consequently, mechanical properties of the subendothelial ECM and endothelial actomyosin contractility that mediate the endothelial forces also impact the endothelium's resistance to cancer cell transmigration. These results indicate that mechanical features of distant tissues, including force interactions between the endothelium and the subendothelial ECM, are key determinants of metastatic organotropism.

When survey science met web tracking: Presenting an error framework for metered data

Metered data, also called web-tracking data, are generally collected from a sample of participants who willingly install or configure, onto their devices, technologies that track digital traces left when people go online (e.g., URLs visited). Since metered data allow for the observation of online behaviours unobtrusively, it has been proposed as a useful tool to understand what people do online and what impacts this might have on online and offline phenomena. It is crucial, nevertheless, to understand its limitations. Although some research have explored the potential errors of metered data, a systematic categorisation and conceptualisation of these errors are missing. Inspired by the Total Survey Error, we present a Total Error framework for digital traces collected with Meters (TEM). The TEM framework (1) describes the data generation and the analysis process for metered data and (2) documents the sources of bias and variance that may arise in each step of this process. Using a case study we also show how the TEM can be applied in real life to identify, quantify and reduce metered data errors. Results suggest that metered data might indeed be affected by the error sources identified in our framework and, to some extent, biased. This framework can help improve the quality of both stand-alone metered data research projects, as well as foster the understanding of how and when survey and metered data can be combined.

Long transient response of vegetation dynamics after four millennia of anthropogenic impacts in an island ecosystem

Agents of global change commonly have a higher impact on island ecosystem dynamics. In the Mediterranean region, those dynamics have historically been influenced by anthropogenic impacts, for example, the introduction of invasive species and overharvesting of resources. Here, we analysed the spatio-temporal dynamics of vegetation in sa Dragonera island, which experienced a large environmental change ca. 4000 years ago by the arrival of humans. Anthropogenic impacts, such as herbivory by goats and over-logging, ended in the 1970s, while in 2011 the site became the largest Mediterranean island where rats were eradicated. Invasive rats and goats played the ecological role of two endemic species, the cave goat and the giant dormouse, which inhabited the island for more than 5 million years and were rapidly extinct by humans. We used Landsat imagery to explore NDVI as a proxy of vegetation productivity over the years 1984-2021, orthophotos to assess changes in land and vegetation covers and historical plant inventories to study the dynamics in plant diversity. Results showed that those indicators steadily increased both in spring and in summer, while the noise around the trends was partially explained by climate variability. The regime shifts in the temporal dynamics of vegetation productivity suggested a transient from a perturbed to a non-perturbed stable state. Trends in successional dynamics, spatial self-organization and plant diversity also showed the same type of transient dynamics. Historical perturbations related to harvesting (mainly the synergies between goat browsing, burning and forest over-logging) were more important than rat eradication or the influence of climate to explain the vegetation dynamics. Our study shows the transient nature of this small island ecosystem after 4000 years of perturbations and its current path towards vegetation dynamics more controlled by ecological interactions lacking large herbivores and omnivores, drought dynamics and the carrying capacity of the island.

Decellularization of xenografted tumors provides cell-specific in vitro 3D environment

In vitro cell culture studies are common in the cancer research field, and reliable biomimetic 3D models are needed to ensure physiological relevance. In this manuscript, we hypothesized that decellularized xenograft tumors can serve as an optimal 3D substrate to generate a top-down approach for in vitro tumor modeling. Multiple tumor cell lines were xenografted and the formed solid tumors were recovered for their decellularization by several techniques and further characterization by histology and proteomics techniques. Selected decellularized tumor xenograft samples were seeded with the HCC1806 human triple-negative breast cancer (TNBC) basal-like subtype cell line, and cell behavior was compared among them and with other control 2D and 3D cell culture methods. A soft treatment using Freeze-EDTA-DNAse allows proper decellularization of xenografted tumor samples. Interestingly, proteomic data show that samples decellularized from TNBC basal-like subtype xenograft models had different extracellular matrix (ECM) compositions compared to the rest of the xenograft tumors tested. The in vitro recellularization of decellularized ECM (dECM) yields tumor-type–specific cell behavior in the TNBC context. Data show that dECM derived from xenograft tumors is a feasible substrate for reseeding purposes, thereby promoting tumor-type–specific cell behavior. These data serve as a proof-of-concept for further potential generation of patient-specific in vitro research models.

A Brain Region-Specific Expression Profile for Genes Within Large Introgression Deserts and Under Positive Selection in Homo sapiens

Analyses of ancient DNA from extinct hominins have provided unique insights into the complex evolutionary history of Homo sapiens, intricately related to that of the Neanderthals and the Denisovans as revealed by several instances of admixture events. These analyses have also allowed the identification of introgression deserts: genomic regions in our species that are depleted of “archaic” haplotypes. The presence of genes like FOXP2 in these deserts has been taken to be suggestive of brain-related functional differences between Homo species. Here, we seek a deeper characterization of these regions and the specific expression trajectories of genes within them, taking into account signals of positive selection in our lineage. Analyzing publicly available transcriptomic data from the human brain at different developmental stages, we found that structures outside the cerebral neocortex, in particular the cerebellum, the striatum and the mediodorsal nucleus of the thalamus show the most divergent transcriptomic profiles when considering genes within large introgression deserts and under positive selection.

Resilience of seagrass populations to thermal stress does not reflect regional differences in ocean climate

The prevalence of local adaptation and phenotypic plasticity among populations is critical to accurately predicting when and where climate change impacts will occur. Currently, comparisons of thermal performance between populations are untested for most marine species or overlooked by models predicting the thermal sensitivity of species to extirpation. Here we compared the ecological response and recovery of seagrass populations (Posidonia oceanica) to thermal stress throughout a year-long translocation experiment across a 2800-km gradient in ocean climate. Transplants in central and warm-edge locations experienced temperatures > 29°C, representing thermal anomalies > 5°C above long-term maxima for cool-edge populations, 1.5°C for central and < 1°C for warm-edge populations. Cool-edge, central and warm-edge populations differed in thermal performance when grown under common conditions, but patterns contrasted with expectations based on thermal geography. Cool-edge populations did not differ from warm-edge populations under common conditions and performed significantly better than central populations in growth and survival. Our findings reveal that thermal performance does not necessarily reflect the thermal geography of a species. We demonstrate that warm-edge populations can be less sensitive to thermal stress than cooler, central populations suggesting that Mediterranean seagrasses have greater resilience to warming than current paradigms suggest.

Do polyproline II helix associations modulate biomolecular condensates?

Biomolecular condensates are microdroplets that form inside cells and serve to selectively concentrate proteins, RNAs and other molecules for a variety of physiological functions, but can contribute to cancer, neurodegenerative diseases and viral infections. The formation of these condensates is driven by weak, transient interactions between molecules. These weak associations can operate at the level of whole protein domains, elements of secondary structure or even moieties composed of just a few atoms. Different types of condensates do not generally combine to form larger microdroplets, suggesting that each uses a distinct class of attractive interactions. Here, we address whether polyproline II (PPII) helices mediate condensate formation. By combining with PPII-binding elements such as GYF, WW, profilin, SH3 or OCRE domains, PPII helices help form lipid rafts, nuclear speckles, P-body-like neuronal granules, enhancer complexes and other condensates. The number of PPII helical tracts or tandem PPII-binding domains can strongly influence condensate stability. Many PPII helices have a low content of proline residues, which hinders their identification. Recently, we characterized the NMR spectral properties of a Gly-rich, Pro-poor protein composed of six PPII helices. Based on those results, we predicted that many Gly-rich segments may form PPII helices and interact with PPII-binding domains. This prediction is being tested and could join the palette of verified interactions contributing to biomolecular condensate formation.