Activation of Shh/Smo is sufficient to maintain oligodendrocyte precursor cells in an undifferentiated state and is not necessary for myelin formation and (re)myelination

Myelination is the terminal step in a complex and precisely timed program that orchestrates the proliferation, migration and differentiation of oligodendroglial cells. It is thought that Sonic Hedgehog (Shh) acting on Smoothened (Smo) participates in regulating this process, but that these effects are highly context dependent. Here, we investigate oligodendroglial development and remyelination from three specific transgenic lines: NG2-CreERT2 (control), Smofl/fl/NG2-CreERT2 (loss of function), and SmoM2/NG2-CreERT2 (gain of function), as well as pharmacological manipulation that enhance or inhibit the Smo pathway (Smoothened Agonist (SAG) or cyclopamine treatment, respectively). To explore the effects of Shh/Smo on differentiation and myelination in vivo, we developed a highly quantifiable model by transplanting oligodendrocyte precursor cells (OPCs) in the retina. We find that myelination is greatly enhanced upon cyclopamine treatment and hypothesize that Shh/Smo could promote OPC proliferation to subsequently inhibit differentiation. Consistent with this hypothesis, we find that the genetic activation of Smo significantly increased numbers of OPCs and decreased oligodendrocyte differentiation when we examined the corpus callosum during development and after cuprizone demyelination and remyelination. However, upon loss of function with the conditional ablation of Smo, myelination in the same scenarios are unchanged. Taken together, our present findings suggest that the Shh pathway is sufficient to maintain OPCs in an undifferentiated state, but is not necessary for myelination and remyelination.

Constitutional adaptation to pKa modulation by remote ester hydrolysis

The mechanisms through which environmental conditions affect the expression of interconnected species is a key step to comprehending the principles underlying complex chemical processes. In Nature, chemical modifications triggered by the environment have a major impact on the structure and function of biomolecules and regulate different reaction pathways. Yet, minimalistic artificial systems implementing related adaptation behaviours remain barely explored. The hydrolysis of amino acid methyl esters to their corresponding amino acids leads to a drastic change in pKa (ca. 7 and 9, respectively) that protonates the free amino group at physiological conditions. Dynamic covalent libraries (DCvLs) based on amino acid methyl esters and aldehydes respond to such hydrolysis and lead to constitutional adaptation. Each of the libraries studied experiences a DCvL conversion allowing for constituent selection due to the silencing of the zwitterionic amino acids towards imine formation. The selective action of different enzymes on the DCvLs results in states with simplified constitutional distributions and transient chirality. When additional components (i.e., scavengers) that are not affected by hydrolysis are introduced into the dynamic libraries, the amino acid methyl ester hydrolysis induces the up-regulation of the constituents made of these scavenging components. In these systems, the constituent distribution is resolved from a scrambled mixture of imines to a state characterized by the predominance of a single aldimine. Remarkably, although the final libraries display higher "simplexity", the different transient states present an increased complexity that allows for the emergence of organized structures [micelle formation] and distributions [up-regulation of two antagonistic constituents]. This reactive site inhibition by a remote chemical modification resembles the scenario found in some enzymes for the regulation of their activity through proximal post-translational modifications.

Use of pure recombinant human enzymes to assess the disease-causing potential of missense mutations in urea cycle disorders, applied to N-acetylglutamate synthase deficiency

N-acetylglutamate synthase (NAGS) makes acetylglutamate, the essential activator of the first, regulatory enzyme of the urea cycle, carbamoyl phosphate synthetase 1 (CPS1). NAGS deficiency (NAGSD) and CPS1 deficiency (CPS1D) present identical phenotypes. However, they must be distinguished, because NAGSD is cured by substitutive therapy with the N-acetyl-L-glutamate analogue N-carbamyl-L-glutamate, while curative therapy of CPS1D requires liver transplantation. Since their differentiation is done genetically, it is important to ascertain the disease-causing potential of CPS1 and NAGS genetic variants. With this goal, we previously carried out site-directed mutagenesis studies with pure recombinant human CPS1. We could not do the same with human NAGS (HuNAGS) because of enzyme instability, leading to our prior utilization of a bacterial NAGS as an imperfect surrogate of HuNAGS. We now use genuine HuNAGS, stabilized as a chimera of its conserved domain (cHuNAGS) with the maltose binding protein (MBP), and produced in Escherichia coli. MBP-cHuNAGS linker cleavage allowed assessment of the enzymatic properties and thermal stability of cHuNAGS, either wild-type or hosting each one of 23 nonsynonymous single-base changes found in NAGSD patients. For all but one change, disease causation was accounted by the enzymatic alterations identified, including, depending on the variant, loss of arginine activation, increased Km Glutamate, active site inactivation, decreased thermal stability, and protein misfolding. Our present approach outperforms experimental in vitro use of bacterial NAGS or in silico utilization of prediction servers (including AlphaMissense), illustrating with HuNAGS the value for UCDs of using recombinant enzymes for assessing disease-causation and molecular pathogenesis, and for therapeutic guidance.

Variations and trade-offs in leaf and culm functional traits among 77 woody bamboo species

BACKGROUND

Woody bamboos are the only diverse large perennial grasses in mesic-wet forests and are widely distributed in the understory and canopy. The functional trait variations and trade-offs in this taxon remain unclear due to woody bamboo syndromes (represented by lignified culm of composed internodes and nodes). Here, we examined the effects of heritable legacy and occurrence site climates on functional trait variations in leaf and culm across 77 woody bamboo species in a common garden. We explored the trade-offs among leaf functional traits, the connection between leaf nitrogen (N), phosphorus (P) concentrations and functional niche traits, and the correlation of functional traits between leaves and culms.

RESULTS

The Bayesian mixed models reveal that the combined effects of heritable legacy (phylogenetic distances and other evolutionary processes) and occurrence site climates accounted for 55.10-90.89% of the total variation among species for each studied trait. The standardized major axis analysis identified trade-offs among leaf functional traits in woody bamboo consistent with the global leaf economics spectrum; however, compared to non-bamboo species, the woody bamboo exhibited lower leaf mass per area but higher N, P concentrations and assimilation, dark respiration rates. The canonical correlation analysis demonstrated a positive correlation (ρ = 0.57, P-value < 0.001) between leaf N, P concentrations and morphophysiology traits. The phylogenetic principal components and trait network analyses indicated that leaf and culm traits were clustered separately, with leaf assimilation and respiration rates associated with culm ground diameter.

CONCLUSION

Our study confirms the applicability of the leaf economics spectrum and the biogeochemical niche in woody bamboo taxa, improves the understanding of woody bamboo leaf and culm functional trait variations and trade-offs, and broadens the taxonomic units considered in plant functional trait studies, which contributes to our comprehensive understanding of terrestrial forest ecosystems.

Tinostamustine (EDO-S101), an Alkylating Deacetylase Inhibitor, Enhances the Efficacy of Daratumumab in Multiple Myeloma by Upregulation of CD38 and NKG2D Ligands

Multiple myeloma is a malignancy characterized by the accumulation of malignant plasma cells in bone marrow and the production of monoclonal immunoglobulin. A hallmark of cancer is the evasion of immune surveillance. Histone deacetylase inhibitors have been shown to promote the expression of silenced molecules and hold potential to increase the anti-MM efficacy of immunotherapy. The aim of the present work was to assess the potential effect of tinostamustine (EDO-S101), a first-in-class alkylating deacetylase inhibitor, in combination with daratumumab, an anti-CD38 monoclonal antibody (mAb), through different preclinical studies. Tinostamustine increases CD38 expression in myeloma cell lines, an effect that occurs in parallel with an increment in CD38 histone H3 acetylation levels. Also, the expression of MICA and MICB, ligands for the NK cell activating receptor NKG2D, augments after tinostamustine treatment in myeloma cell lines and primary myeloma cells. Pretreatment of myeloma cell lines with tinostamustine increased the sensitivity of these cells to daratumumab through its different cytotoxic mechanisms, and the combination of these two drugs showed a higher anti-myeloma effect than individual treatments in ex vivo cultures of myeloma patients' samples. In vivo data confirmed that tinostamustine pretreatment followed by daratumumab administration significantly delayed tumor growth and improved the survival of mice compared to individual treatments. In summary, our results suggest that tinostamustine could be a potential candidate to improve the efficacy of anti-CD38 mAbs.

Impact of aridity rise and arid lands expansion on carbon-storing capacity, biodiversity loss, and ecosystem services

Drylands, comprising semi-arid, arid, and hyperarid regions, cover approximately 41% of the Earth's land surface and have expanded considerably in recent decades. Even under more optimistic scenarios, such as limiting global temperature rise to 1.5°C by 2100, semi-arid lands may increase by up to 38%. This study provides an overview of the state-of-the-art regarding changing aridity in arid regions, with a specific focus on its effects on the accumulation and availability of carbon (C), nitrogen (N), and phosphorus (P) in plant-soil systems. Additionally, we summarized the impacts of rising aridity on biodiversity, service provisioning, and feedback effects on climate change across scales. The expansion of arid ecosystems is linked to a decline in C and nutrient stocks, plant community biomass and diversity, thereby diminishing the capacity for recovery and maintaining adequate water-use efficiency by plants and microbes. Prolonged drought led to a -3.3% reduction in soil organic carbon (SOC) content (based on 148 drought-manipulation studies), a -8.7% decrease in plant litter input, a -13.0% decline in absolute litter decomposition, and a -5.7% decrease in litter decomposition rate. Moreover, a substantial positive feedback loop with global warming exists, primarily due to increased albedo. The loss of critical ecosystem services, including food production capacity and water resources, poses a severe challenge to the inhabitants of these regions. Increased aridity reduces SOC, nutrient, and water content. Aridity expansion and intensification exacerbate socio-economic disparities between economically rich and least developed countries, with significant opportunities for improvement through substantial investments in infrastructure and technology. By 2100, half the world's landmass may become dryland, characterized by severe conditions marked by limited C, N, and P resources, water scarcity, and substantial loss of native species biodiversity. These conditions pose formidable challenges for maintaining essential services, impacting human well-being and raising complex global and regional socio-political challenges.

Uppermost global tree elevations are primarily limited by low temperature or insufficient moisture

The impact of anthropogenic global warming has induced significant upward dispersal of trees to higher elevations at alpine treelines. Assessing vertical deviation from current uppermost tree distributions to potential treeline positions is crucial for understanding ecosystem responses to evolving global climate. However, due to data resolution constraints and research scale limitation, comprehending the global pattern of alpine treeline elevations and driving factors remains challenging. This study constructed a comprehensive quasi-observational dataset of uppermost tree distribution across global mountains using Google Earth imagery. Validating the isotherm of mean growing-season air temperature at 6.6 ± 0.3°C as the global indicator of thermal treeline, we found that around two-thirds of uppermost tree distribution records significantly deviated from it. Drought conditions constitute the primary driver in 51% of cases, followed by mountain elevation effect which indicates surface heat (27%). Our analyses underscore the multifaceted determinants of global patterns of alpine treeline, explaining divergent treeline responses to climate warming. Moisture, along with temperature and disturbance, plays the most fundamental roles in understanding global variation of alpine treeline elevation and forecasting alpine treeline response to ongoing global warming.

RTS,S/AS02A Malaria Vaccine-Induced IgG Responses Equally Recognize Native-Like Fucosylated and Nonfucosylated Plasmodium falciparum Circumsporozoite Proteins

The RTS,S/AS02A malaria vaccine is based on the Plasmodium falciparum circumsporozoite protein (PfCSP), which is O-fucosylated on the sporozoite surface. We determined whether RTS,S/AS02A-induced immunoglobulin G (IgG) antibodies recognize vaccine-like nonfucosylated PfCSP better than native-like fucosylated PfCSP. Similar to previous vaccine trials, RTS,S/AS02A vaccination induced high anti-PfCSP IgG levels associated with malaria protection. IgG recognition of nonfucosylated and fucosylated PfCSP was equivalent, suggesting that PfCSP fucosylation does not affect antibody recognition. Clinical Trials Registration. NCT00197041.

Influence of body mass index on health complains and life satisfaction

PURPOSE

This research work investigates the influence of children's weight status on well-being and school context in a sample of Spanish adolescences.

METHODS

The Spanish records from the 2013-14 Health Behaviour in School-Aged Children Survey are used, which gathers 9,565 adolescences aged 11, 13 and 15. Studies do not usually address the endogeneity of body mass index when analysing their effect on life satisfaction and health complaints, thus resulting in biased estimates. Considering the endogeneity of body mass index, we use the frequency of alcohol consumption as an instrumental variable in order to obtain consistent estimates of its influence.

RESULTS

The two-stage least squares estimation shows that children's body mass index has a significant negative influence on health complaints and it conditions the way children relate to each other at school. Likewise, results report significant influence on children's subjective well-being and their self-assessment of general health.

CONCLUSIONS

The results of this study provide compelling evidence that BMI plays a crucial role in shaping adolescents' well-being and their interactions with peers at school. These findings underscore the importance of addressing childhood overweight and promoting healthy body mass index levels. Furthermore, the study highlights the need for targeted policy interventions to combat the social stigma associated with being overweight, fostering a more inclusive and supportive school environment for all students.

The ATPase Inhibitory Factor 1 (IF1) Contributes to the Warburg Effect and Is Regulated by Its Phosphorylation in S39 by a Protein Kinase A-like Activity

The relevant role played by the ATPase Inhibitory Factor 1 (IF1) as a physiological in vivo inhibitor of mitochondrial ATP synthase in cancer and non-cancer cells, and in the mitochondria of different mouse tissues, as assessed in different genetic loss- and gain-of-function models of IF1 has been extensively documented. In this review we summarize our findings and those of others that favor the implication of IF1 in metabolic reprogramming to an enhanced glycolytic phenotype, which is mediated by its binding and inhibition of the ATP synthase. Moreover, we emphasize that IF1 is phosphorylated in vivo in its S39 by the c-AMP-dependent PKA activity of mitochondria to render an inactive inhibitor that is unable to interact with the enzyme, thus triggering the activation of ATP synthase. Overall, we discuss and challenge the results that argue against the role of IF1 as in vivo inhibitor of mitochondrial ATP synthase and stress that IF1 cannot be regarded solely as a pro-oncogenic protein because in some prevalent carcinomas, it prevents metastatic disease.

Synthesis of Cobalt-Based Nanoparticles as Catalysts for Methanol Synthesis from CO2 Hydrogenation

The increasing emission of carbon dioxide into the atmosphere has urged the scientific community to investigate alternatives to alleviate such emissions, being that they are the principal contributor to the greenhouse gas effect. One major alternative is carbon capture and utilization (CCU) toward the production of value-added chemicals using diverse technologies. This work aims at the study of the catalytic potential of different cobalt-derived nanoparticles for methanol synthesis from carbon dioxide hydrogenation. Thanks to its abundance and cost efficacy, cobalt can serve as an economical catalyst compared to noble metal-based catalysts. In this work, we present a systematic comparison among different cobalt and cobalt oxide nanocomposites in terms of their efficiency as catalysts for carbon dioxide hydrogenation to methanol as well as how different supports, zeolites, MnO2, and CeO2, can enhance their catalytic capacity. The oxygen vacancies in the cerium oxide act as carbon dioxide adsorption and activation sites, which facilitates a higher methanol production yield.

Acetylcholine modulates the precision of prediction error in the auditory cortex

A fundamental property of sensory systems is their ability to detect novel stimuli in the ambient environment. The auditory brain contains neurons that decrease their response to repetitive sounds but increase their firing rate to novel or deviant stimuli; the difference between both responses is known as stimulus-specific adaptation or neuronal mismatch (nMM). Here, we tested the effect of microiontophoretic applications of ACh on the neuronal responses in the auditory cortex (AC) of anesthetized rats during an auditory oddball paradigm, including cascade controls. Results indicate that ACh modulates the nMM, affecting prediction error responses but not repetition suppression, and this effect is manifested predominantly in infragranular cortical layers. The differential effect of ACh on responses to standards, relative to deviants (in terms of averages and variances), was consistent with the representational sharpening that accompanies an increase in the precision of prediction errors. These findings suggest that ACh plays an important role in modulating prediction error signaling in the AC and gating the access of these signals to higher cognitive levels.

Neurofilament Light Chain as a Biomarker of Neuronal Damage in Children With Malaria

Malaria can cause brain injury. Neurofilament light chain (NfL) is a biomarker of neuronal damage. Here we examined longitudinal plasma NfL levels in children aged 1-12 years with uncomplicated and severe malaria from Mozambique. NfL levels were similar in all malaria cases at hospital admission. However, levels increased over time and the increment was significantly higher in severe malaria cases with neurological manifestations (ie, coma, impaired consciousness, or repeated seizures). NfL may be useful to identify and quantify brain injury in malaria.

Red-light modulated ortho-chloro azobenzene photoswitch for peptide stapling via aromatic substitution

The application of peptide stapling using photoswitchable linkers has gained notable interest for potential therapeutic applications. However, many existing methodologies of photoswitching still rely on the use of tissue-damaging and weakly skin-penetrating UV light. Herein, we describe the development of a tetra-ortho-chloro azobenzene linker that was successfully used for cysteine-selective peptide stapling via SNAr. This linker facilitates precise photocontrol of peptide structure via trans to cis isomerisation under red light irradiation. As a proof-of-concept, we applied the developed peptide stapling platform to a modified PMI peptide, targeting the inhibition of MDM2/p53 protein-protein interaction (PPI). Biophysical characterisation of the photoswitchable peptide by competitive fluorescence polarisation showed a significant difference in affinity between the trans and cis isomer for the p53-interacting domain of the human MDM2. Remarkably, the cis isomer displayed a >240-fold higher potency. To the best of our knowledge, this is the highest reported difference in binding affinity between isoforms of a photoswitchable therapeutic peptide. Overall, our findings demonstrate the potential of this novel photoswitchable peptide stapling system for tuneable, selective modulation of PPIs via visible-light isomerisation with deeply-tissue penetrating red light.

The soil-borne white root rot pathogen Rosellinia necatrix expresses antimicrobial proteins during host colonization

Rosellinia necatrix is a prevalent soil-borne plant-pathogenic fungus that is the causal agent of white root rot disease in a broad range of host plants. The limited availability of genomic resources for R. necatrix has complicated a thorough understanding of its infection biology. Here, we sequenced nine R. necatrix strains with Oxford Nanopore sequencing technology, and with DNA proximity ligation we generated a gapless assembly of one of the genomes into ten chromosomes. Whereas many filamentous pathogens display a so-called two-speed genome with more dynamic and more conserved compartments, the R. necatrix genome does not display such genome compartmentalization. It has recently been proposed that fungal plant pathogens may employ effectors with antimicrobial activity to manipulate the host microbiota to promote infection. In the predicted secretome of R. necatrix, 26 putative antimicrobial effector proteins were identified, nine of which are expressed during plant colonization. Two of the candidates were tested, both of which were found to possess selective antimicrobial activity. Intriguingly, some of the inhibited bacteria are antagonists of R. necatrix growth in vitro and can alleviate R. necatrix infection on cotton plants. Collectively, our data show that R. necatrix encodes antimicrobials that are expressed during host colonization and that may contribute to modulation of host-associated microbiota to stimulate disease development.

The JAK3Q988P mutation reveals oncogenic potential and resistance to ruxolitinib

T-cell acute lymphoblastic leukemia (T-ALL) arises from the malignant transformation of T-cell progenitors at various differentiation stages. Given that patients who relapse have a dismal prognosis, there is an urgent need to identify the molecular alterations that are present in such patients and promote leukemogenesis to implement personalized therapies with higher efficacy and fewer adverse effects. In the present manuscript, we identified the JAK3Q988P mutation in a T-ALL patient who did not achieve a durable response after the conventional treatment and whose tumor cells at relapse presented constitutive activation of the JAK/STAT pathway. Although JAK3Q988P has been previously identified in T-ALL patients from different studies, the functional consequences exerted by this mutation remain unexplored. Through the combination of different hematopoietic cellular models, we functionally characterize JAK3Q988P as an oncogenic mutation that contributes to leukemogenesis. Notably, JAK3Q988P not only promotes constitutive activation of the JAK/STAT pathway in the absence of cytokines and growth factors, as is the case for other JAK3 mutations that have been functionally characterized as oncogenic, but also functions independently of JAK1 and IL2RG, resulting in high oncogenic potential as well as resistance to ruxolitinib. Our results indicate that ruxolitinib may not be efficient for future patients bearing the JAK3Q988P mutation who instead may obtain greater benefits from treatments involving other pharmacological inhibitors such as tofacitinib.

Updating cancer research with patient-focused networks

Multidisciplinary patient-centered networks offer access to difficult-to-get samples and initiate projects from human material. Improving such networks to include 'living' samples could be transformative, not only for research but for clinical trial design, especially when focused on unmet clinical needs, such as brain metastasis.

Efficacy of a benzothiazole-based LRRK2 inhibitor in oligodendrocyte precursor cells and in a murine model of multiple sclerosis

AIMS

Multiple sclerosis (MS) is a chronic neurological disease that currently lacks effective curative treatments. There is a need to find effective therapies, especially to reverse the progressive demyelination and neuronal damage. Oligodendrocytes form the myelin sheath around axons in the central nervous system (CNS) and oligodendrocyte precursor cells (OPCs) undergo mechanisms that enable spontaneously the partial repair of damaged lesions. The aim of this study was to discover small molecules with potential effects in demyelinating diseases, including (re)myelinating properties.

METHODS

Recently, it has been shown how LRRK2 inhibition promotes oligodendrogliogenesis and therefore an efficient repair or myelin damaged lesions. Here we explored small molecules inhibiting LRRK2 as potential enhancers of primary OPCs proliferation and differentiation, and their potential impact on the clinical score of experimental autoimmune encephalomyelitys (EAE) mice, a validated model of the most frequent clinical form of MS, relapsing-remitting MS.

RESULTS

One of the LRRK2 inhibitors presented in this study promoted the proliferation and differentiation of OPC primary cultures. When tested in the EAE murine model of MS, it exerted a statistically significant reduction of the clinical burden of the animals, and histological evidence revealed how the treated animals presented a reduced lesion area in the spinal cord.

CONCLUSIONS

For the first time, a small molecule with LRRK2 inhibition properties presented (re)myelinating properties in primary OPCs cultures and potentially in the in vivo murine model. This study provides an in vivo proof of concept for a LRRK2 inhibitor, confirming its potential for the treatment of MS.

The effects of an exercise intervention on neuroelectric activity and executive function in children with overweight/obesity: The ActiveBrains randomized controlled trial

OBJECTIVE

To investigate whether a 20-week aerobic and resistance exercise program induces changes in brain current density underlying working memory and inhibitory control in children with overweight/obesity.

METHODS

A total of 67 children (10.00 ± 1.10 years) were randomized into an exercise or control group. Electroencephalography (EEG)-based current density (μA/mm2 ) was estimated using standardized low-resolution brain electromagnetic tomography (sLORETA) during a working memory task (Delayed non-matched-to-sample task, DNMS) and inhibitory control task (Modified flanker task, MFT). In DNMS, participants had to memorize four stimuli (Pokemons) and then select between two of them, one of which had not been previously shown. In MFT, participants had to indicate whether the centered cow (i.e., target) of five faced the right or left.

RESULTS

The exercise group had significantly greater increases in brain activation in comparison with the control group during the encoding phase of DNMS, particularly during retention of second stimuli in temporal and frontal areas (peak t = from 3.4 to 3.8, cluster size [k] = from 11 to 39), during the retention of the third stimuli in frontal areas (peak t = from 3.7 to 3.9, k = from 15 to 26), and during the retention of the fourth stimuli in temporal and occipital areas (peak t = from 2.7 to 4.3, k = from 13 to 101). In MFT, the exercise group presented a lower current density change in the middle frontal gyrus (peak t = -4.1, k = 5). No significant change was observed between groups for behavioral performance (p ≥ 0.05).

CONCLUSION

A 20-week exercise program modulates brain activity which might provide a positive influence on working memory and inhibitory control in children with overweight/obesity.

Effects of a N-Maleimide-derivatized Phosphatidylethanolamine on the Architecture and Properties of Lipid Bilayers

N-maleimide-derivatized phospholipids are often used to facilitate protein anchoring to membranes. In autophagy studies, this is applied to the covalent binding of Atg8, an autophagy protein, to a phosphatidylethanolamine (PE) in the nascent autophagosome. However, the question remains on how closely the N-maleimide PE derivative (PE-mal) mimicks the native PE in the bilayer. In the present paper, spectroscopic and calorimetric techniques have been applied to vesicles containing either PE or PE-mal (together with other phospholipids) to compare the properties of the native and derivatized forms of PE. According to differential scanning calorimetry, and to infrared spectroscopy, the presence of PE-mal did not perturb the fatty acyl chains in the bilayer. Fluorescence spectroscopy and microscopy showed that PE-mal did not alter the bilayer permeability either. However, fluorescence emission polarization of the Laurdan and DPH probes indicated an increased order, or decreased fluidity, in the bilayers containing PE-mal. In addition, the infrared spectral data from the phospholipid phosphate region revealed a PE-mal-induced conformational change in the polar heads, accompanied by increased hydration. Globally considered, the results suggest that PE-mal would be a reasonable substitute for PE in model membranes containing reconstituted proteins.

GRF2 Is Crucial for Cone Photoreceptor Viability and Ribbon Synapse Formation in the Mouse Retina

Using constitutive GRF1/2 knockout mice, we showed previously that GRF2 is a key regulator of nuclear migration in retinal cone photoreceptors. To evaluate the functional relevance of that cellular process for two putative targets of the GEF activity of GRF2 (RAC1 and CDC42), here we compared the structural and functional retinal phenotypes resulting from conditional targeting of RAC1 or CDC42 in the cone photoreceptors of constitutive GRF2KO and GRF2WT mice. We observed that single RAC1 disruption did not cause any obvious morphological or physiological changes in the retinas of GRF2WT mice, and did not modify either the phenotypic alterations previously described in the retinal photoreceptor layer of GRF2KO mice. In contrast, the single ablation of CDC42 in the cone photoreceptors of GRF2WT mice resulted in clear alterations of nuclear movement that, unlike those of the GRF2KO retinas, were not accompanied by electrophysiological defects or slow, progressive cone cell degeneration. On the other hand, the concomitant disruption of GRF2 and CDC42 in the cone photoreceptors resulted, somewhat surprisingly, in a normalized pattern of nuclear positioning/movement, similar to that physiologically observed in GRF2WT mice, along with worsened patterns of electrophysiological responses and faster rates of cell death/disappearance than those previously recorded in single GRF2KO cone cells. Interestingly, the increased rates of cone cell apoptosis/death observed in single GRF2KO and double-knockout GRF2KO/CDC42KO retinas correlated with the electron microscopic detection of significant ultrastructural alterations (flattening) of their retinal ribbon synapses that were not otherwise observed at all in single-knockout CDC42KO retinas. Our observations identify GRF2 and CDC42 (but not RAC1) as key regulators of retinal processes controlling cone photoreceptor nuclear positioning and survival, and support the notion of GRF2 loss-of-function mutations as potential drivers of cone retinal dystrophies.

Warming-induced phenological mismatch between trees and shrubs explains high-elevation forest expansion

Despite the importance of species interaction in modulating the range shifts of plants, little is known about the responses of coexisting life forms to a warmer climate. Here, we combine long-term monitoring of cambial phenology in sympatric trees and shrubs at two treelines of the Tibetan Plateau, with a meta-analysis of ring-width series from 344 shrubs and 575 trees paired across 11 alpine treelines in the Northern Hemisphere. Under a spring warming of +1°C, xylem resumption advances by 2-4 days in trees, but delays by 3-8 days in shrubs. The divergent phenological response to warming was due to shrubs being 3.2 times more sensitive than trees to chilling accumulation. Warmer winters increased the thermal requirement for cambial reactivation in shrubs, leading to a delayed response to warmer springs. Our meta-analysis confirmed such a mechanism across continental scales. The warming-induced phenological mismatch may give a competitive advantage to trees over shrubs, which would provide a new explanation for increasing alpine treeline shifts under the context of climate change.

Neurofilament Light Chain Protein in Plasma and Extracellular Vesicles Is Associated with Minimal Hepatic Encephalopathy and Responses to Rifaximin Treatment in Cirrhotic Patients

Neurofilament light chain protein (NfL) levels reflect neuronal damage in several neurological diseases and have been proposed as a possible biomarker. Plasma extracellular vesicles (EVs) could play an important role as mediators of the inflammatory changes associated with inducing minimal hepatic encephalopathy (MHE) in cirrhotic patients. This study investigated the association of NfL levels in plasma and EVs with the presence of MHE in cirrhotic patients, and with responses to rifaximin treatment. The NfL levels in plasma and EVs were assessed in 71 patients with liver cirrhosis (40 with MHE and 31 without MHE) and 26 controls. A total of 31 patients with MHE received rifaximin treatment. We examined changes in NfL levels in plasma and EVs before and after 6 months of rifaximin treatment. The NfL measures were correlated with cognitive alterations and plasma inflammatory cytokines. MHE patients showed increased plasma levels of NfL, which were reverted after rifaximin treatment in patients who responded to treatment. The NfL content in EVs also showed a reversal pattern in MHE patients treated with rifaximin. In multivariable analyses, NfL levels were independently associated with the presence of MHE. We also showed that patients with high levels of both ammonia and fractalkine had significantly higher NfL levels than patients with low levels of least one of these parameters. Rifaximin treatment in MHE patients showed promising results in improving axonal damage, suggesting that rifaximin may have therapeutic benefits against disease progression in MHE.

Supramolecular multivalency effects enhance imine formation in aqueous medium allowing for dynamic modification of enzymatic activity

Imine formation under physiological conditions represents a challenging reaction due to the strong propensity of aldimines to be hydrolyzed. Herein we disclose the remarkable effect of supramolecular multivalency on increasing imine stability. A family of reactive aldehydes was synthesized bearing supramolecularly-active sites within their structure. The imine formation activity for such aldehydes was evaluated and compared with model aldehydes. The reaction of the best-performing species - containing two carboxylate groups-with a set of amines showed a significant decrease in imine yields as the degree of supramolecular multivalency between sidechains decreased. The reversible conjugation of amino acid derivatives and small peptides was also assayed, with excellent selectivities for the imine formation at the Nα position even in substrates containing competing sites. Preliminary results on protein bioconjugation revealed that a model enzyme could be dynamically inhibited upon reaction with the aldehyde, with its native activity being recovered by displacing the imine bonds with a suitable chemical effector (i.e., acylhydrazide).

Chimeric hemagglutinin split vaccines elicit broadly cross-reactive antibodies and protection against group 2 influenza viruses in mice

Seasonal influenza virus vaccines are effective when they are well matched to circulating strains. Because of antigenic drift/change in the immunodominant hemagglutinin (HA) head domain, annual vaccine reformulations are necessary to maintain a match with circulating strains. In addition, seasonal vaccines provide little to no protection against newly emerging pandemic strains. Sequential vaccination with chimeric HA (cHA) constructs has been proven to direct the immune response toward the immunosubdominant but more conserved HA stalk domain. In this study, we show that immunization with group 2 cHA split vaccines in combination with the CpG 1018 adjuvant elicits broadly cross-reactive antibodies against all group 2 HAs, as well as systemic and local antigen-specific T cell responses. Antibodies elicited after sequential vaccination are directed to conserved regions of the HA such as the stalk and the trimer interface and also to the N2 neuraminidase (NA). Immunized mice were fully protected from challenge with a broad panel of influenza A viruses.

Use of sera cell free DNA (cfDNA) and exovesicle-DNA for the molecular diagnosis of chronic Chagas disease

Chagas disease, a neglected tropical disease, is now considered a worldwide health concern as a result of migratory movements from Central and South America to other regions that were considered free of the disease, and where the epidemiological risk is limited to transplacental transmission or blood or organ donations from infected persons. Parasite detection in chronically ill patients is restricted to serological tests that only determine infection by previous infection and not the presence of the parasite, especially in patients undergoing treatment evaluation or in newborns. We have evaluated the use of nucleic acids from both circulating exovesicles and cell-free DNA (cfDNA) from 50 samples twice randomly selected from a total of 448 serum samples from immunologically diagnosed patients in whom the presence of the parasite was confirmed by nested PCR on amplicons resulting from amplification with kinetoplastid DNA-specific primers 121F-122R. Six samples were randomly selected to quantify the limit of detection by qPCR in serum exovesicles. When the nucleic acids thus purified were assayed as a template and amplified with kinetoplastid DNA and nuclear satellite DNA primers, a 100% positivity rate was obtained for all positive samples assayed with kDNA-specific primers and 96% when SAT primers were used. However, isolation of cfDNA for Trypanosoma cruzi and amplification with SAT also showed 100% positivity. The results demonstrate that serum exovesicles contain DNA of mitochondrial and nuclear origin, which can be considered a mixed population of exovesicles of parasitic origin. The results obtained with serum samples prove that both cfDNA and Exovesicle DNA can be used to confirm parasitaemia in chronically ill patients or in samples where it is necessary to demonstrate the active presence of the parasite. The results confirm for the first time the existence of exovesicles of mitochondrial origin of the parasite in the serum of those affected by Chagas disease.

GSK-3β orchestrates the inhibitory innervation of adult-born dentate granule cells in vivo

Adult hippocampal neurogenesis enhances brain plasticity and contributes to the cognitive reserve during aging. Adult hippocampal neurogenesis is impaired in neurological disorders, yet the molecular mechanisms regulating the maturation and synaptic integration of new neurons have not been fully elucidated. GABA is a master regulator of adult and developmental neurogenesis. Here we engineered a novel retrovirus encoding the fusion protein Gephyrin:GFP to longitudinally study the formation and maturation of inhibitory synapses during adult hippocampal neurogenesis in vivo. Our data reveal the early assembly of inhibitory postsynaptic densities at 1 week of cell age. Glycogen synthase kinase 3 Beta (GSK-3β) emerges as a key regulator of inhibitory synapse formation and maturation during adult hippocampal neurogenesis. GSK-3β-overexpressing newborn neurons show an increased number and altered size of Gephyrin+ postsynaptic clusters, enhanced miniature inhibitory postsynaptic currents, shorter and distanced axon initial segments, reduced synaptic output at the CA3 and CA2 hippocampal regions, and impaired pattern separation. Moreover, GSK-3β overexpression triggers a depletion of Parvalbumin+ interneuron perineuronal nets. These alterations might be relevant in the context of neurological diseases in which the activity of GSK-3β is dysregulated.

UHRF1 is a mediator of KRAS driven oncogenesis in lung adenocarcinoma

KRAS is a frequent driver in lung cancer. To identify KRAS-specific vulnerabilities in lung cancer, we performed RNAi screens in primary spheroids derived from a Kras mutant mouse lung cancer model and discovered an epigenetic regulator Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1). In human lung cancer models UHRF1 knock-out selectively impaired growth and induced apoptosis only in KRAS mutant cells. Genome-wide methylation and gene expression analysis of UHRF1-depleted KRAS mutant cells revealed global DNA hypomethylation leading to upregulation of tumor suppressor genes (TSGs). A focused CRISPR/Cas9 screen validated several of these TSGs as mediators of UHRF1-driven tumorigenesis. In vivo, UHRF1 knock-out inhibited tumor growth of KRAS-driven mouse lung cancer models. Finally, in lung cancer patients high UHRF1 expression is anti-correlated with TSG expression and predicts worse outcomes for patients with KRAS mutant tumors. These results nominate UHRF1 as a KRAS-specific vulnerability and potential target for therapeutic intervention.

Mild Cognitive Impairment Is Associated with Enhanced Activation of Th17 Lymphocytes in Non-Alcoholic Fatty Liver Disease

Patients with nonalcoholic fatty liver disease (NAFLD) may show mild cognitive impairment (MCI). The mechanisms involved remain unclear. The plasma concentrations of several cytokines and chemokines were measured in 71 NAFLD patients (20 with and 51 without MCI) and 61 controls. Characterization and activation of leukocyte populations and CD4⁺ sub-populations were carried out and analyzed by flow cytometry. We analyzed the cytokines released from CD4⁺ cell cultures and the mRNA expression of transcription factors and receptors in peripheral blood mononuclear cells. The appearance of MCI in NAFLD patients was associated with increased activation of CD4⁺ T lymphocytes, mainly of the Th17 subtype, increased plasma levels of pro-inflammatory and anti-inflammatory cytokines such as IL-17A, IL-23, IL-21, IL-22, IL-6, INF-γ, and IL-13, and higher expression of the CCR2 receptor. Constitutive expression of IL-17 was found in cultures of CD4⁺ cells from MCI patients, reflecting Th17 activation. High IL-13 plasma levels were predictive of MCI and could reflect a compensatory anti-inflammatory response to the increased expression of pro-inflammatory cytokines. This study identified some specific alterations of the immune system associated with the appearance of neurological alterations in MCI patients with NAFLD that could be the basis to improve and restore cognitive functions and quality of life in these patients.

Optimization of a Green Microwave-Assisted Extraction Method to Obtain Multifunctional Extracts of Mentha sp

A microwave-assisted extraction (MAE) procedure has been optimized to simultaneously provide multifunctional extracts of Mentha sp. leaves with improved antioxidant properties and, for the first time, with optimal antimicrobial activity. Among the solvents evaluated, water was selected as the extractant in order to develop a green procedure and also for its improved bioactive properties (higher TPC and Staphylococcus aureus inhibition halo). MAE operating conditions were optimized by means of a 3-level factorial experimental design (100 °C, 14.7 min, 1 g of dry leaves/12 mL of water and 1 extraction cycle), and further applied to the extraction of bioactives from 6 different Mentha species. A comparative LC-Q MS and LC-QToF MS analysis of these MAE extracts was carried out for the first time in a single study, allowing the characterization of up to 40 phenolics and the quantitation of the most abundant. Antioxidant, antimicrobial (Staphylococcus aureus, Escherichia coli and Salmonella typhimurium) and antifungal (Candida albicans) activities of MAE extracts depended on the Mentha species considered. In conclusion, the new MAE method developed here is shown as a green and efficient approach to provide multifunctional Mentha sp. extracts with an added value as natural food preservatives.

Extracellular vesicles of trypomastigotes of Trypanosoma cruzi induce changes in ubiquitin-related processes, cell-signaling pathways and apoptosis

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi. The disease has an acute and a chronic phase in which approximately 30% of the chronic patients suffer from heart disease and/or gastrointestinal symptoms. The pathogenesis of the disease is multifactorial and involves the virulence of the strains, immunological factors and extracellular vesicles (EV) shed by the parasite which participate in cell-cell communication and evasion of the immune response. In this work, we present a transcriptomic analysis of cells stimulated with EV of the trypomastigote stage of T. cruzi. Results after EV-cell incubation revealed 322 differentially expressed genes (168 were upregulated and 154 were downregulated). In this regard, the overexpression of genes related to ubiquitin-related processes (Ube2C, SUMO1 and SUMO2) is highlighted. Moreover, the expression of Rho-GTPases (RhoA, Rac1 and Cdc42) after the interaction was analyzed, revealing a downregulation of the analyzed genes after 4 h of interaction. Finally, a protective role of EV over apoptosis is suggested, as relative values of cells in early and late apoptosis were significantly lower in EV-treated cells, which also showed increased CSNK1G1 expression. These results contribute to a better understanding of the EV-cell interaction and support the role of EV as virulence factors.

'Getting to Denmark': the role of agricultural elites for development

We explore the role of elites for development and the spread of industrialized dairying in Denmark in the 1880s. We demonstrate that the location of early proto-modern dairies, introduced by landowning elites from northern Germany in the eighteenth century, explains the location of industrialized dairying in 1890: an increase of one standard deviation in elite influence increases industrialized dairying by 56 percent of the mean exposure in one specification. We interpret this as evidence for a spread of ideas from the elites to the peasantry, which we capture through measures of specialization in dairying and demand for education and identify a causal relationship using an instrument based on distance to the influential first mover. Finally, we demonstrate that areas with cooperatives enjoyed greater wealth by the twentieth century, and that they are today associated with other Danish cultural attributes: a belief in democracy and individualism.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10887-023-09226-8.

Methods to study adult hippocampal neurogenesis in humans and across the phylogeny

The hippocampus hosts the continuous addition of new neurons throughout life-a phenomenon named adult hippocampal neurogenesis (AHN). Here we revisit the occurrence of AHN in more than 110 mammalian species, including humans, and discuss the further validation of these data by single-cell RNAseq and other alternative techniques. In this regard, our recent studies have addressed the long-standing controversy in the field, namely whether cells positive for AHN markers are present in the adult human dentate gyrus (DG). Here we review how we developed a tightly controlled methodology, based on the use of high-quality brain samples (characterized by short postmortem delays and ≤24 h of fixation in freshly prepared 4% paraformaldehyde), to address human AHN. We review that the detection of AHN markers in samples fixed for 24 h required mild antigen retrieval and chemical elimination of autofluorescence. However, these steps were not necessary for samples subjected to shorter fixation periods. Moreover, the detection of labile epitopes (such as Nestin) in the human hippocampus required the use of mild detergents. The application of this strictly controlled methodology allowed reconstruction of the entire AHN process, thus revealing the presence of neural stem cells, proliferative progenitors, neuroblasts, and immature neurons at distinct stages of differentiation in the human DG. The data reviewed here demonstrate that methodology is of utmost importance when studying AHN by means of distinct techniques across the phylogenetic scale. In this regard, we summarize the major findings made by our group that emphasize that overlooking fundamental technical principles might have consequences for any given research field.

Bioengineered extracellular vesicles: future of precision medicine for sepsis

Sepsis is a syndromic response to infection and is frequently a final common pathway to death from many infectious diseases worldwide. The complexity and high heterogeneity of sepsis hinder the possibility to treat all patients with the same protocol, requiring personalized management. The versatility of extracellular vesicles (EVs) and their contribution to sepsis progression bring along promises for one-to-one tailoring sepsis treatment and diagnosis. In this article, we critically review the endogenous role of EVs in sepsis progression and how current advancements have improved EVs-based therapies toward their translational future clinical application, with innovative strategies to enhance EVs effect. More complex approaches, including hybrid and fully synthetic nanocarriers that mimic EVs, are also discussed. Several pre-clinical and clinical studies are examined through the review to offer a general outlook of the current and future perspectives of EV-based sepsis diagnosis and treatment.

Pathogenic variants in GCSH encoding the moonlighting H-protein cause combined nonketotic hyperglycinemia and lipoate deficiency

Maintaining protein lipoylation is vital for cell metabolism. The H-protein encoded by GCSH has a dual role in protein lipoylation required for bioenergetic enzymes including pyruvate dehydrogenase and 2-ketoglutarate dehydrogenase, and in the one-carbon metabolism through its involvement in glycine cleavage enzyme system, intersecting two vital roles for cell survival. Here, we report six patients with biallelic pathogenic variants in GCSH and a broad clinical spectrum ranging from neonatal fatal glycine encephalopathy to an attenuated phenotype of developmental delay, behavioral problems, limited epilepsy and variable movement problems. The mutational spectrum includes one insertion c.293-2_293-1insT, one deletion c.122_(228 + 1_229-1) del, one duplication of exons 4 and 5, one nonsense variant p.Gln76*and four missense p.His57Arg, p.Pro115Leu and p.Thr148Pro and the previously described p.Met1?. Via functional studies in patient's fibroblasts, molecular modeling, expression analysis in GCSH knockdown COS7 cells and yeast, and in vitro protein studies, we demonstrate for the first time that most variants identified in our cohort produced a hypomorphic effect on both mitochondrial activities, protein lipoylation and glycine metabolism, causing combined deficiency, whereas some missense variants affect primarily one function only. The clinical features of the patients reflect the impact of the GCSH changes on any of the two functions analyzed. Our analysis illustrates the complex interplay of functional and clinical impact when pathogenic variants affect a multifunctional protein involved in two metabolic pathways and emphasizes the value of the functional assays to select the treatment and investigate new personalized options.

Distinct patterns of soil bacterial and fungal community assemblages in subtropical forest ecosystems under warming

Climate change globally affects soil microbial community assembly across ecosystems. However, little is known about the impact of warming on the structure of soil microbial communities or underlying mechanisms that shape microbial community composition in subtropical forest ecosystems. To address this gap, we utilized natural variation in temperature via an altitudinal gradient to simulate ecosystem warming. After 6 years, microbial co-occurrence network complexity increased with warming, and changes in their taxonomic composition were asynchronous, likely due to contrasting community assembly processes. We found that while stochastic processes were drivers of bacterial community composition, warming led to a shift from stochastic to deterministic drivers in dry season. Structural equation modelling highlighted that soil temperature and water content positively influenced soil microbial communities during dry season and negatively during wet season. These results facilitate our understanding of the response of soil microbial communities to climate warming and may improve predictions of ecosystem function of soil microbes in subtropical forests.

A systematic review of risk factors for mortality among tuberculosis patients in South Africa

BACKGROUND

Tuberculosis (TB)-associated mortality in South Africa remains high. This review aimed to systematically assess risk factors associated with death during TB treatment in South African patients.

METHODS

We conducted a systematic review of TB research articles published between 2010 and 2018. We searched BioMed Central (BMC), PubMed®, EBSCOhost, Cochrane, and SCOPUS for publications between January 2010 and December 2018. Searches were conducted between August 2019 and October 2019. We included randomised control trials (RCTs), case control, cross sectional, retrospective, and prospective cohort studies where TB mortality was a primary endpoint and effect measure estimates were provided for risk factors for TB mortality during TB treatment. Due to heterogeneity in effect measures and risk factors evaluated, a formal meta-analysis of risk factors for TB mortality was not appropriate. A random effects meta-analysis was used to estimate case fatality ratios (CFRs) for all studies and for specific subgroups so that these could be compared. Quality assessments were performed using the Newcastle-Ottawa scale or the Cochrane Risk of Bias Tool.

RESULTS

We identified 1995 titles for screening, 24 publications met our inclusion criteria (one cross-sectional study, 2 RCTs, and 21 cohort studies). Twenty-two studies reported on adults (n = 12561) and two were restricted to children < 15 years of age (n = 696). The CFR estimated for all studies was 26.4% (CI 18.1-34.7, n = 13257 ); 37.5% (CI 24.8-50.3, n = 5149) for drug-resistant (DR) TB; 12.5% (CI 1.1-23.9, n = 1935) for drug-susceptible (DS) TB; 15.6% (CI 8.1-23.2, n = 6173) for studies in which drug susceptibility was mixed or not specified; 21.3% (CI 15.3-27.3, n = 7375) for people living with HIV/AIDS (PLHIV); 19.2% (CI 7.7-30.7, n = 1691) in HIV-negative TB patients; and 6.8% (CI 4.9-8.7, n = 696) in paediatric studies. The main risk factors associated with TB mortality were HIV infection, prior TB treatment, DR-TB, and lower body weight at TB diagnosis.

CONCLUSIONS

In South Africa, overall mortality during TB treatment remains high, people with DR-TB have an elevated risk of mortality during TB treatment and interventions to mitigate high mortality are needed. In addition, better prospective data on TB mortality are needed, especially amongst vulnerable sub-populations including young children, adolescents, pregnant women, and people with co-morbidities other than HIV. Limitations included a lack of prospective studies and RCTs and a high degree of heterogeneity in risk factors and comparator variables.

SYSTEMATIC REVIEW REGISTRATION

The systematic review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42018108622. This study was funded by the Bill and Melinda Gates Foundation (Investment ID OPP1173131) via the South African TB Think Tank.

Technological advances in fibrin for tissue engineering

Fibrin is a promising natural polymer that is widely used for diverse applications, such as hemostatic glue, carrier for drug and cell delivery, and matrix for tissue engineering. Despite the significant advances in the use of fibrin for bioengineering and biomedical applications, some of its characteristics must be improved for suitability for general use. For example, fibrin hydrogels tend to shrink and degrade quickly after polymerization, particularly when they contain embedded cells. In addition, their poor mechanical properties and batch-to-batch variability affect their handling, long-term stability, standardization, and reliability. One of the most widely used approaches to improve their properties has been modification of the structure and composition of fibrin hydrogels. In this review, recent advances in composite fibrin scaffolds, chemically modified fibrin hydrogels, interpenetrated polymer network (IPN) hydrogels composed of fibrin and other synthetic or natural polymers are critically reviewed, focusing on their use for tissue engineering.

Human Trypanosoma cruzi chronic infection leads to individual level steady-state parasitemia: Implications for drug-trial optimization in Chagas disease

Currently available drugs against Trypanosoma cruzi infection, which causes 12000 deaths annually, have limitations in their efficacy, safety and tolerability. The evaluation of therapeutic responses to available and new compounds is based on parasite detection in the bloodstream but remains challenging because a substantial proportion of infected individuals have undetectable parasitemia even when using diagnostic tools with the highest accuracy. We characterize parasite dynamics which might impact drug efficacy assessments in chronic Chagas by analyzing pre- and post-treatment quantitative-PCR data obtained from blood samples collected regularly over a year. We show that parasitemia remains at a steady-state independently of the diagnostic sensitivity. This steady-state can be probabilistically quantified and robustly predicted at an individual level. Furthermore, individuals can be assigned to categories with distinct parasitological status, allowing a more detailed evaluation of the efficacy outcomes and adjustment for potential biases. Our analysis improves understanding of parasite dynamics and provides a novel background for optimizing future drug efficacy trials in Chagas disease. Trial Registration: original trial registered with ClinicalTrials.gov, number NCT01489228.

The Myth of The Annular Lipids

In the early 1970s, the existence of a "lipid annulus" stably surrounding the individual intrinsic protein molecules was proposed by several authors. They referred to a number of lipid molecules in slow exchange with the bulk lipid in the bilayer, i.e., more or less protein-bound, and more ordered than the bulk lipid. The annular lipids would control enzyme activity. This idea was uncritically accepted by most scientists working with intrinsic membrane proteins at the time, so that the idea operated like a myth in the field. However, in the following decade, hard spectroscopic and biochemical evidence showed that the proposed annular lipids were not immobilized for a sufficiently long time to influence enzyme or transporter activity, nor were they ordered by the protein. Surprisingly, forty years later, the myth survives, and the term 'annular lipid' is still in use, in a different, but even more illogical sense.

Small extracellular vesicles from young adipose-derived stem cells prevent frailty, improve health span, and decrease epigenetic age in old mice

Aging is associated with an increased risk of frailty, disability, and mortality. Strategies to delay the degenerative changes associated with aging and frailty are particularly interesting. We treated old animals with small extracellular vesicles (sEVs) derived from adipose mesenchymal stem cells (ADSCs) of young animals, and we found an improvement in several parameters usually altered with aging, such as motor coordination, grip strength, fatigue resistance, fur regeneration, and renal function, as well as an important decrease in frailty. ADSC-sEVs induced proregenerative effects and a decrease in oxidative stress, inflammation, and senescence markers in muscle and kidney. Moreover, predicted epigenetic age was lower in tissues of old mice treated with ADSC-sEVs and their metabolome changed to a youth-like pattern. Last, we gained some insight into the microRNAs contained in sEVs that might be responsible for the observed effects. We propose that young sEV treatment can promote healthy aging.

Alhagi sparsifolia acclimatizes to saline stress by regulating its osmotic, antioxidant, and nitrogen assimilation potential

BACKGROUND

Alhagi sparsifolia (Camelthorn) is a leguminous shrub species that dominates the Taklimakan desert's salty, hyperarid, and infertile landscapes in northwest China. Although this plant can colonize and spread in very saline soils, how it adapts to saline stress in the seedling stage remains unclear so a pot-based experiment was carried out to evaluate the effects of four different saline stress levels (0, 50, 150, and 300 mM) on the morphological and physio-biochemical responses in A. sparsifolia seedlings.

RESULTS

Our results revealed that N-fixing A. sparsifolia has a variety of physio-biochemical anti-saline stress acclimations, including osmotic adjustments, enzymatic mechanisms, and the allocation of metabolic resources. Shoot-root growth and chlorophyll pigments significantly decreased under intermediate and high saline stress. Additionally, increasing levels of saline stress significantly increased Na⁺ but decreased K⁺ concentrations in roots and leaves, resulting in a decreased K⁺/Na⁺ ratio and leaves accumulated more Na + and K + ions than roots, highlighting their ability to increase cellular osmolarity, favouring water fluxes from soil to leaves. Salt-induced higher lipid peroxidation significantly triggered antioxidant enzymes, both for mass-scavenging (catalase) and cytosolic fine-regulation (superoxide dismutase and peroxidase) of H₂O₂. Nitrate reductase and glutamine synthetase/glutamate synthase also increased at low and intermediate saline stress levels but decreased under higher stress levels. Soluble proteins and proline rose at all salt levels, whereas soluble sugars increased only at low and medium stress. The results show that when under low-to-intermediate saline stress, seedlings invest more energy in osmotic adjustments but shift their investment towards antioxidant defense mechanisms under high levels of saline stress.

CONCLUSIONS

Overall, our results suggest that A. sparsifolia seedlings tolerate low, intermediate, and high salt stress by promoting high antioxidant mechanisms, osmolytes accumulations, and the maintenance of mineral N assimilation. However, a gradual decline in growth with increasing salt levels could be attributed to the diversion of energy from growth to maintain salinity homeostasis and anti-stress oxidative mechanisms.

Progression of Alzheimer's disease parallels unusual structural plasticity of human dentate granule cells

Alzheimer´s disease (AD), the most common form of dementia in industrialized countries, severely targets the hippocampal formation in humans and mouse models of this condition. The adult hippocampus hosts the continuous addition of new dentate granule cells (DGCs) in numerous mammalian species, including humans. Although the morphology and positioning of DGCs within the granule cell layer (GCL) match their developmental origin in rodents, a similar correlation has not been reported in humans to date. Our data reveal that DGCs located in inner portions of the human GCL show shorter and less complex dendrites than those found in outer portions of this layer, which are presumably generated developmentally. Moreover, in AD patients, DGCs show early morphological alterations that are further aggravated as the disease progresses. An aberrantly increased number of DGCs with several primary apical dendrites is the first morphological change detected in patients at Braak-Tau I/II stages. This alteration persists throughout AD progression and leads to generalized dendritic atrophy at late stages of the disease. Our data reveal the distinct vulnerability of several morphological characteristics of DGCs located in the inner and outer portions of the GCL to AD and support the notion that the malfunction of the hippocampus is related to cognitive impairments in patients with AD.

Evaluation of antibody serology to determine current helminth and Plasmodium falciparum infections in a co-endemic area in Southern Mozambique

Background

Soil-transmitted helminths (STH), Schistosoma spp. and Plasmodium falciparum are parasites of major public health importance and co-endemic in many sub-Saharan African countries. Management of these infections requires detection and treatment of infected people and evaluation of large-scale measures implemented. Diagnostic tools are available but their low sensitivity, especially for low intensity helminth infections, leaves room for improvement. Antibody serology could be a useful approach thanks to its potential to detect both current infection and past exposure.

Methodology

We evaluated total IgE responses and specific-IgG levels to 9 antigens from STH, 2 from Schistosoma spp., and 16 from P. falciparum, as potential markers of current infection in a population of children and adults from Southern Mozambique (N = 715). Antibody responses were measured by quantitative suspension array Luminex technology and their performance was evaluated by ROC curve analysis using microscopic and molecular detection of infections as reference.

Principal findings

IgG against the combination of EXP1, AMA1 and MSP2 (P. falciparum) in children and NIE (Strongyloides stercoralis) in adults and children had the highest accuracies (AUC = 0.942 and AUC = 0.872, respectively) as markers of current infection. IgG against the combination of MEA and Sm25 (Schistosoma spp.) were also reliable markers of current infection (AUC = 0.779). In addition, IgG seropositivity against 20 out of the 27 antigens in the panel differentiated the seropositive endemic population from the non-endemic population, suggesting a possible role as markers of exposure although sensitivity could not be assessed.

Conclusions

We provided evidence for the utility of antibody serology to detect current infection with parasites causing tropical diseases in endemic populations. In addition, most of the markers have potential good specificity as markers of exposure. We also showed the feasibility of measuring antibody serology with a platform that allows the integration of control and elimination programs for different pathogens.

Parasitic worms and Plasmodium falciparum, the causal agent of malaria, are among the most relevant parasitic diseases of our time and efforts are under way for their control and, ultimately, elimination. An accurate diagnosis is relevant for case management, but also allows calculating the prevalence and evaluating the effectiveness of treatment and control measures. Unfortunately, current diagnostic methods for parasitic worms are not optimal and many infections remain undetected. As for P. falciparum, current diagnostic techniques are satisfactory but do not allow for ascertaining exposure, which is relevant for evaluating control measures. Here we investigated the utility of measuring antibodies to these parasites as a diagnostic method. Our results indicate that it is possible to detect current infection with parasitic worms and P. falciparum using antibody detection with a moderate to high accuracy. We also show that antibodies against the antigens in this study have potential as markers of exposure. Importantly, we used a platform that allows for the simultaneous detection of immunoglobulins to different parasites, which would be extremely useful as a tool to integrate control and elimination programs for several pathogens.

CK2 alpha prime and alpha-synuclein pathogenic functional interaction mediates synaptic dysregulation in huntington's disease

Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the HTT gene for which no therapies are available. HTT mutation causes protein misfolding and aggregation, preferentially affecting medium spiny neurons (MSNs) of the basal ganglia. Transcriptional perturbations in synaptic genes and neuroinflammation are key processes that precede MSN dysfunction and motor symptom onset. Understanding the interplay between these processes is crucial to develop effective therapeutic strategies to treat HD. We investigated the role of protein kinase CK2α', a kinase upregulated in MSNs in HD and previously associated with Parkinson's disease (PD), in the regulation of neuroinflammation and synaptic function in HD. We used the heterozygous knock-in zQ175 HD mouse model and compared that to zQ175 mice lacking one allele of CK2α' (zQ175:CK2α'(±)). CK2α' haploinsufficiency in zQ175 mice resulted in decreased levels of pro-inflammatory cytokines, HTT aggregation, astrogliosis and transcriptional alterations of synaptic genes related to glutamatergic signaling. zQ175:CK2α'(±) mice also presented increased frequency of striatal miniature excitatory postsynaptic currents (mEPSCs), an indicator of synaptic activity, and improved motor coordination compared to zQ175 mice. Neuropathological and phenotypic changes mediated by CK2α' were connected to alpha-synuclein (α-syn) dysregulation and correlated with differences in α-syn serine 129 phosphorylation (pS129-α-syn), a post-translational modification involved in α-synucleinopathy and shown to be regulated by CK2 in PD. pS129-α-syn was increased in the nuclei of MSNs in zQ175 mice and in the striatum of patients with HD, and it decreased in zQ175:CK2α'(±) mice. Collectively, our data established a novel connection between CK2α', neuroinflammation and synaptic gene dysregulation with synucleinopathy in HD and suggested common molecular mechanisms of neurodegeneration between HD and PD. Our results also support CK2α' inhibition as a potential therapeutic strategy to modulate neuronal function and neuroprotection in HD.

BOSO: A novel feature selection algorithm for linear regression with high-dimensional data

With the frenetic growth of high-dimensional datasets in different biomedical domains, there is an urgent need to develop predictive methods able to deal with this complexity. Feature selection is a relevant strategy in machine learning to address this challenge. We introduce a novel feature selection algorithm for linear regression called BOSO (Bilevel Optimization Selector Operator). We conducted a benchmark of BOSO with key algorithms in the literature, finding a superior accuracy for feature selection in high-dimensional datasets. Proof-of-concept of BOSO for predicting drug sensitivity in cancer is presented. A detailed analysis is carried out for methotrexate, a well-studied drug targeting cancer metabolism.

We present BOSO (Bilevel Optimization Selector Operator), a novel method to conduct feature selection in linear regression models. In machine learning, feature selection consists of identifying the subset of input variables (features) that are correctly associated with the response variable that is aimed to be predicted. An adequate feature selection is particularly relevant for high-dimensional datasets, commonly encountered in biomedical research questions that rely on -omics data, e.g. predictive models of drug sensitivity, resistance or toxicity, construction of gene regulatory networks, biomarker selection or association studies. The need of feature selection is emphasized in many of these complex problems, since the number of features is greater than the number of samples, which makes it harder to obtain accurate and general predictive models. In this context, we show that the models derived by BOSO make a better combination of accuracy and simplicity than competing approaches in the literature. The relevance of BOSO is illustrated in the prediction of drug sensitivity of cancer cell lines, using RNA-seq data and drug screenings from GDSC (Genomics of Drug Sensitivity in Cancer) database. BOSO obtains linear regression models with a similar level of accuracy but involving a substantially lower number of features, which simplifies the interpretation and validation of predictive models.

Mechanisms linking physical activity with psychiatric symptoms across the lifespan: a protocol for a systematic review

INTRODUCTION

Persistent psychiatric symptomatology during childhood and adolescence predicts vulnerability to experience mental illness in adulthood. Physical activity is well-known to provide mental health benefits across the lifespan. However, the underlying mechanisms linking physical activity and psychiatric symptoms remain underexplored. In this context, we aim to systematically synthesise evidence focused on the mechanisms through which physical activity might reduce psychiatric symptoms across all ages.

METHODS AND ANALYSIS

With the aid of a biomedical information specialist, we will develop a systematic search strategy based on the predetermined research question in the following electronic databases: MEDLINE, Embase, Web of Science, Cochrane and PsycINFO. Two independent reviewers will screen and select studies, extract data and assess the risk of bias. In case of inability to reach a consensus, a third person will be consulted. We will not apply any language restriction, and we will perform a qualitative synthesis of our findings as we anticipate that studies are scarce and heterogeneous.

ETHICS AND DISSEMINATION

Only data that have already been published will be included. Then, ethical approval is not required. Findings will be published in a peer-reviewed journal and presented at conferences. Additionally, we will communicate our findings to healthcare providers and other sections of society (eg, through regular channels, including social media).

PROSPERO REGISTRATION NUMBER

CRD42021239440.

Identification of a New Cholesterol-Binding Site within the IFN-γ Receptor that is Required for Signal Transduction

The cytokine interferon-gamma (IFN-γ) is a master regulator of innate and adaptive immunity involved in a broad array of human diseases that range from atherosclerosis to cancer. IFN-γ exerts it signaling action by binding to a specific cell surface receptor, the IFN-γ receptor (IFN-γR), whose activation critically depends on its partition into lipid nanodomains. However, little is known about the impact of specific lipids on IFN-γR signal transduction activity. Here, a new conserved cholesterol (chol) binding motif localized within its single transmembrane domain is identified. Through direct binding, chol drives the partition of IFN-γR2 chains into plasma membrane lipid nanodomains, orchestrating IFN-γR oligomerization and transmembrane signaling. Bioinformatics studies show that the signature sequence stands for a conserved chol-binding motif presented in many mammalian membrane proteins. The discovery of chol as the molecular switch governing IFN-γR transmembrane signaling represents a significant advance for understanding the mechanism of lipid selectivity by membrane proteins, but also for figuring out the role of lipids in modulating cell surface receptor function. Finally, this study suggests that inhibition of the chol-IFNγR2 interaction may represent a potential therapeutic strategy for various IFN-γ-dependent diseases.

Down-regulation of the bacterial protein biosynthesis machinery in response to weeks, years, and decades of soil warming

How soil microorganisms respond to global warming is key to infer future soil-climate feedbacks, yet poorly understood. Here, we applied metatranscriptomics to investigate microbial physiological responses to medium-term (8 years) and long-term (>50 years) subarctic grassland soil warming of +6°C. Besides indications for a community-wide up-regulation of centralmetabolic pathways and cell replication, we observed a down-regulation of the bacterial protein biosynthesis machinery in the warmed soils, coinciding with a lower microbial biomass, RNA, and soil substrate content. We conclude that permanently accelerated reaction rates at higher temperatures and reduced substrate concentrations result in cellular reduction of ribosomes, the macromolecular complexes carrying out protein biosynthesis. Later efforts to test this, including a short-term warming experiment (6 weeks, +6°C), further supported our conclusion. Down-regulating the protein biosynthesis machinery liberates energy and matter, allowing soil bacteria to maintain high metabolic activities and cell division rates even after decades of warming.