Ectopic expression of the AtCDF1 transcription factor in potato enhances tuber starch and amino acid contents and yield under open field conditions

INTRODUCTION

Cycling Dof transcription factors (CDFs) have been involved in different aspects of plant growth and development. In Arabidopsis and tomato, one member of this family (CDF1) has recently been associated with the regulation of primary metabolism and abiotic stress responses, but their roles in crop production under open field conditions remain unknown.

METHODS

In this study, we compared the growth, and tuber yield and composition of plants ectopically expressing the CDF1 gene from Arabidopsis under the control of the 35S promoter with wild-type (WT) potato plants cultured in growth chamber and open field conditions.

RESULTS

In growth chambers, the 35S::AtCDF1 plants showed a greater tuber yield than the WT by increasing the biomass partition for tuber development. Under field conditions, the ectopic expression of CDF1 also promoted the sink strength of the tubers, since 35S::AtCDF1 plants exhibited significant increases in tuber size and weight resulting in higher tuber yield. A metabolomic analysis revealed that tubers of 35S::AtCDF1 plants cultured under open field conditions accumulated higher levels of glucose, starch and amino acids than WT tubers. A comparative proteomic analysis of tubers of 35S::AtCDF1 and WT plants cultured under open field conditions revealed that these changes can be accounted for changes in the expression of proteins involved in energy production and different aspects of C and N metabolism.

DISCUSSION

The results from this study advance our collective understanding of the role of CDFs and are of great interest for the purposes of improving the yield and breeding of crop plants.

The molecular conformation, but not disaggregation, of humic acid in water solution plays a crucial role in promoting plant development in the natural environment

Many studies have shown the capacity of soil humic substances (HS) to improve plant growth in natural ecosystems. This effect involves the activation of different processes within the plant at different coordinated molecular, biochemical, and physiological levels. However, the first event triggered by plant root-HS interaction remains unclear. Some studies suggest the hypothesis that the interaction of HS with root exudates involves relevant modification of the molecular conformation of humic self-assembled aggregates, including disaggregation, which might be directly involved in the activation of root responses. To investigate this hypothesis, we have prepared two humic acids. A natural humic acid (HA) and a transformed humic acid obtained from the treatment of HA with fungal laccase (HA enz). We have tested the capacity of the two humic acids to affect plant growth (cucumber and Arabidopsis) and complex Cu. Laccase-treatment did not change the molecular size but increased hydrophobicity, molecular compactness and stability, and rigidity of HA enz. Laccase-treatment avoided the ability of HA to promote shoot- and root-growth in cucumber and Arabidopsis. However, it does not modify Cu complexation features. There is no molecular disaggregation upon the interaction of HA and HA enz with plant roots. The results indicate that the interaction with plant roots induced in both HA and laccase-treated HA (HA enz), changes in their structural features that showed higher compactness and rigidity. These events might result from the interaction of HA and HA enz with specific root exudates that can promote intermolecular crosslinking. In summary, the results indicate that the weakly bond stabilized aggregated conformation (supramolecular-like) of HA plays a crucial role in its ability to promote root and shoot growth. The results also indicate the presence of two main types of HS in the rhizosphere corresponding to those non-interacting with plant roots (forming aggregated molecular assemblies) and those produced after interacting with plant root exudates (forming stable macromolecules).

Identification of HLA class I-restricted immunogenic neoantigens in triple negative breast cancer

Immune checkpoint inhibitor (ICI)-based immunotherapy in triple negative breast cancer (TNBC) is achieving limited therapeutic results, requiring the development of more potent strategies. Combination of ICI with vaccination strategies would enhance antitumor immunity and response rates to ICI in patients having poorly infiltrated tumors. In heavily mutated tumors, neoantigens (neoAgs) resulting from tumor mutations have induced potent responses when used as vaccines. Thus, our aim was the identification of immunogenic neoAgs suitable as vaccines in TNBC patients. By using whole exome sequencing, RNAseq and HLA binding algorithms of tumor samples from a cohort of eight TNBC patients, we identified a median of 60 mutations/patient, which originated a putative median number of 98 HLA class I-restricted neoAgs. Considering a group of 27 predicted neoAgs presented by HLA-A*02:01 allele in two patients, peptide binding to HLA was experimentally confirmed in 63% of them, whereas 55% were immunogenic in vivo in HLA-A*02:01⁺ transgenic mice, inducing T-cells against the mutated but not the wild-type peptide sequence. Vaccination with peptide pools or DNA plasmids expressing these neoAgs induced polyepitopic T-cell responses, which recognized neoAg-expressing tumor cells. These results suggest that TNBC tumors harbor neoAgs potentially useful in therapeutic vaccines, opening the way for new combined immunotherapies.

Gemcitabine-mediated depletion of immunosuppressive dendritic cells enhances the efficacy of therapeutic vaccination

Vaccination using optimized strategies may increase response rates to immune checkpoint inhibitors (ICI) in some tumors. To enhance vaccine potency and improve thus responses to ICI, we analyzed the gene expression profile of an immunosuppressive dendritic cell (DC) population induced during vaccination, with the goal of identifying druggable inhibitory mechanisms. RNAseq studies revealed targetable genes, but their inhibition did not result in improved vaccines. However, we proved that immunosuppressive DC had a monocytic origin. Thus, monocyte depletion by gemcitabine administration reduced the generation of these DC and increased vaccine-induced immunity, which rejected about 20% of LLC-OVA and B16-OVA tumors, which are non-responders to anti-PD-1. This improved efficacy was associated with higher tumor T-cell infiltration and overexpression of PD-1/PD-L1. Therefore, the combination of vaccine + gemcitabine with anti-PD-1 was superior to anti-PD-1 monotherapy in both models. B16-OVA tumors benefited from a synergistic effect, reaching 75% of tumor rejection, but higher levels of exhausted T-cells in LLC-OVA tumors co-expressing PD-1, LAG3 and TIM3 precluded similar levels of efficacy. Our results indicate that gemcitabine is a suitable combination therapy with vaccines aimed at enhancing PD-1 therapies by targeting vaccine-induced immunosuppressive DC.

Inhibiting Histone and DNA Methylation Improves Cancer Vaccination in an Experimental Model of Melanoma

Immunotherapy has improved the treatment of malignant skin cancer of the melanoma type, yet overall clinical response rates remain low. Combination therapies could be key to meet this cogent medical need. Because epigenetic hallmarks represent promising combination therapy targets, we studied the immunogenic potential of a dual inhibitor of histone methyltransferase G9a and DNA methyltransferases (DNMTs) in the preclinical B16-OVA melanoma model. Making use of tumor transcriptomic and functional analyses, methylation-targeted epigenetic reprogramming was shown to induce tumor cell cycle arrest and apoptosis in vitro coinciding with transient tumor growth delay and an IFN-I response in immune-competent mice. In consideration of a potential impact on immune cells, the drug was shown not to interfere with dendritic cell maturation or T-cell activation in vitro. Notably, the drug promoted dendritic cell and, to a lesser extent, T-cell infiltration in vivo, yet failed to sensitize tumor cells to programmed cell death-1 inhibition. Instead, it increased therapeutic efficacy of TCR-redirected T cell and dendritic cell vaccination, jointly increasing overall survival of B16-OVA tumor-bearing mice. The reported data confirm the prospect of methylation-targeted epigenetic reprogramming in melanoma and sustain dual G9a and DNMT inhibition as a strategy to tip the cancer-immune set-point towards responsiveness to active and adoptive vaccination against melanoma.

TNF-α-Secreting Lung Tumor-Infiltrated Monocytes Play a Pivotal Role During Anti-PD-L1 Immunotherapy

Immune checkpoint blockade (ICB) of the PD-1 pathway revolutionized the survival forecast for advanced non-small cell lung cancer (NSCLC). Yet, the majority of PD-L1⁺ NSCLC patients are refractory to anti-PD-L1 therapy. Recent observations indicate a pivotal role for the PD-L1⁺ tumor-infiltrating myeloid cells in therapy failure. As the latter comprise a heterogenous population in the lung tumor microenvironment, we applied an orthotopic Lewis Lung Carcinoma (LLC) model to evaluate 11 different tumor-residing myeloid subsets in response to anti-PD-L1 therapy. While we observed significantly reduced fractions of tumor-infiltrating MHC-II^low macrophages and monocytes, serological levels of TNF-α restored in lung tumor-bearing mice. Notably, we demonstrated in vivo and in vitro that anti-PD-L1 therapy mediated a monocyte-specific production of, and response to TNF-α, further accompanied by their significant upregulation of CD80, VISTA, LAG-3, SIRP-α and TIM-3. Nevertheless, co-blockade of PD-L1 and TNF-α did not reduce LLC tumor growth. A phenomenon that was partly explained by the observation that monocytes and TNF-α play a Janus-faced role in anti-PD-L1 therapy-mediated CTL stimulation. This was endorsed by the observation that monocytes appeared crucial to effectively boost T cell-mediated LLC killing in vitro upon combined PD-L1 with LAG-3 or SIRP-α blockade. Hence, this study enlightens the biomarker potential of lung tumor-infiltrated monocytes to define more effective ICB combination strategies.

Effects of Vivifrail multicomponent intervention on functional capacity: a multicentre, randomized controlled trial

BACKGROUND

Physical exercise is an effective strategy for preserving functional capacity and improving the symptoms of frailty in older adults. In addition to functional gains, exercise is considered to be a cornerstone for enhancing cognitive function in frail older adults with cognitive impairment and dementia. We assessed the effects of the Vivifrail exercise intervention for functional capacity, cognition, and well-being status in community-dwelling older adults.

METHODS

In a multicentre randomized controlled trial conducted in three tertiary hospitals in Spain, a total of 188 older patients with mild cognitive impairment or mild dementia (aged >75 years) were randomly assigned to an exercise intervention (n = 88) or a usual-care, control (n = 100) group. The intervention was based on the Vivifrail tailored multicomponent exercise programme, which included resistance, balance, flexibility (3 days/week), and gait-retraining exercises (5 days/week) and was performed for three consecutive months (http://vivifrail.com). The usual-care group received habitual outpatient care. The main endpoint was change in functional capacity from baseline to 1 and 3 months, assessed with the Short Physical Performance Battery (SPPB). Secondary endpoints were changes in cognitive function and handgrip strength after 1 and 3 months, and well-being status, falls, hospital admission rate, visits to the emergency department, and mortality after 3 months.

RESULTS

The Vivifrail exercise programme provided significant benefits in functional capacity over usual-care. The mean adherence to the exercise sessions was 79% in the first month and 68% in the following 2 months. The intervention group showed a mean increase (over the control group) of 0.86 points on the SPPB scale (95% confidence interval [CI] 0.32, 1.41 points; P < 0.01) after 1 month of intervention and 1.40 points (95% CI 0.82, 1.98 points; P < 0.001) after 3 months. Participants in the usual-care group showed no significant benefit in functional capacity (mean change of -0.17 points [95% CI -0.54, 0.19 points] after 1 month and -0.33 points [95% CI -0.70, 0.04 points] after 3 months), whereas the exercise intervention reversed this trend (0.69 points [95% CI 0.29, 1.09 points] after 1 month and 1.07 points [95% CI 0.63, 1.51 points] after 3 months). Exercise group also obtained significant benefits in cognitive function, muscle function, and depression after 3 months over control group (P < 0.05). No between-group differences were obtained in other secondary endpoints (P > 0.05).

CONCLUSIONS

The Vivifrail exercise training programme is an effective and safe therapy for improving functional capacity in community-dwelling frail/prefrail older patients with mild cognitive impairment or mild dementia and also seems to have beneficial effect on cognition, muscle function, and mood status.

Repercussions of absolute and time-rated BMI "yo-yo" fluctuations on cardiovascular stress-related morbidities within the vascular-metabolic CUN cohort

AIMS

The association between body mass index (BMI) fluctuation and BMI fluctuation rate with cardiovascular stress morbidities in a Caucasian European cohort was evaluated to ascertain the impact of weight cycling.

METHODS

A total of 4,312 patients of the Vascular-Metabolic CUN cohort (VMCUN cohort) were examined and followed up during 9.35 years ( ± 4.39). Cox proportional hazard ratio analyses were performed to assess the risk of developing cardiovascular stress-related diseases (CVDs) across quartiles of BMI fluctuation, measured as the average successive variability (ASV) (ASV = |BMIt0 - BMIt1| + |BMIt1 - BMIt2| + |BMIt2-BMIt3| +…+ |BMItn - 1 - BMItn|/n - 1), and quartiles of BMI fluctuation rate (ASV/year).

RESULTS

There were 436 incident cases of CVD-associated events involving 40,323.32 person-years of follow-up. A progressively increased risk of CVD in subjects with greater ASV levels was found. Also, a higher level of ASV/year was significantly associated with an increased risk of developing CVD stress independent of confounding factors with a value of 3.71 (95% CI: 2.71-5.07) for those in the highest quartile and 1.82 (95% CI: 1.33-2.50) for those in the third quartile.

CONCLUSIONS

The BMI fluctuation rate seems to be a better predictor than BMI fluctuation of the potential development of cardiovascular stress morbidities. The time-rated weight fluctuations are apparently more determinant in increasing the risk of a CVD than the weight fluctuation itself, which is remarkable in subjects under "yo-yo" weight patterns for precision medicine.