The causal relationship between 5 serum lipid parameters and diabetic nephropathy: a Mendelian randomization study.

Background: Serum lipids were found to be correlated with chronic kidney disease and cardiovascular disease. Here, we aimed to research the potential causal associations between five serum lipid parameters and the risk of diabetic nephropathy using several Mendelian Randomization methods. Methods: Genetic data was obtained from the UK Biobank datasets. Causal effects were estimated using multiple MR methods. Heterogeneity and pleiotropy tests were performed. Results: MR analysis revealed that HDL-C and TG exhibited causal associations with diabetic nephropathy (P<0.05). Similar trends were not observed for other lipid parameters. Conclusions: Our research has suggested links between HDL-C, TG and diabetic nephropathy. The findings could contribute to further elucidation of the disease etiology. Strengths and limitations of this study: This article only uses Mendel randomization method to analyze the relationship between blood lipids and diabetes nephropathy, which is more convincing when combined with population data.

Comparing the accuracy of four machine learning models in predicting type 2 diabetes onset within the Chinese population: a retrospective study.

OBJECTIVE: To evaluate the effectiveness of machine learning (ML) models in predicting 5-year type 2 diabetes mellitus (T2DM) risk within the Chinese population by retrospectively analyzing annual health checkup records. METHODS: We included 46,247 patients (32,372 and 13,875 in training and validation sets, respectively) from a national health checkup center database. Univariate and multivariate Cox analyses were performed to identify factors influencing T2DM risk. Extreme Gradient Boosting (XGBoost), support vector machine (SVM), logistic regression (LR), and random forest (RF) models were trained to predict 5-year T2DM risk. Model performances were analyzed using receiver operating characteristic (ROC) curves for discrimination and calibration plots for prediction accuracy. RESULTS: Key variables included fasting plasma glucose, age, and sedentary time. The LR model showed good accuracy with respective areas under the ROC (AUCs) of 0.914 and 0.913 in training and validation sets; the RF model exhibited favorable AUCs of 0.998 and 0.838. In calibration analysis, the LR model displayed good fit for low-risk patients; the RF model exhibited satisfactory fit for low- and high-risk patients. CONCLUSIONS: LR and RF models can effectively predict T2DM risk in the Chinese population. These models may help identify high-risk patients and guide interventions to prevent complications and disabilities.

CD69+ Vδ1γδ T cells are anti-tumor subpopulations in hepatocellular carcinoma.

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC), one of the malignancies with a wide expression of stress ligands recognized by Vδ1γδ T cells, has received much attention in adoptive immunotherapy of γδ T cells. In this study, we aimed to identify the potential anti-tumor Vδ1γδ T subpopulations in HCC. METHODS: Healthy donors (HDs) and HCC patients were recruited from the Affiliated Cancer Hospital of Zhengzhou University. Blood and tumor tissue samples were obtained respectively. Bioinformatics methods were used to analyze total γδ T cells and subsets infiltration, overall survival of HCC patients with high and low infiltration level of Vδ1γδ T cells, and IFNG, granzyme A, granzyme B and perforin expression in TRDV1high/lowCD69high/low groups. CD69 expression and Vδ1γδT cells infiltration in HCC were detected by immunofluorescence. Phenotypic analysis of Vδ1γδ T cells in blood and tumor tissue samples were performed by flow cytometry. RESULTS: Vδ1γδ T cells infiltrating in HCC were associated with better clinical outcome. Study in tumor micro-environment (TME) of HCC demonstrated that not total Vδ1γδ T but CD69+ Vδ1γδ subset infiltration was associated with smaller tumor volume. Moreover, HCC patients simultaneously with high TRDV1 and CD69 expression produced more effector molecules and had longer survival time. Since Vδ1γδ T cells in the tumor microenvironment were often difficult to access, we demonstrated that CD69+ Vδ1γδ T cells also existed in peripheral blood mononuclear cells (PBMC) of HCC and displayed enhanced cytotoxic potentials than HDs. Finally, we investigated the functions and found that CD69+ Vδ1γδ T cells exhibited stronger tumor reactivities when challenged by tumor cells. CONCLUSIONS: CD69+ Vδ1γδ T cells are functional Vδ1γδ T cell subsets in patients with HCC. Circulating CD69+ Vδ1γδ T cell is a promising candidate in immunotherapy of HCC.

Porphyrin-Based Self-Assembled Nanoparticles for PET/MR Imaging of Sentinel Lymph Node Metastasis.

Diagnosing of lymph node metastasis is challenging sometimes, and multimodal imaging offers a promising method to improve the accuracy. This work developed porphyrin-based nanoparticles (68Ga-F127-TAPP/TCPP(Mn) NPs) as PET/MR dual-modal probes for lymph node metastasis imaging by a simple self-assembly method. Compared with F127-TCPP(Mn) NPs, F127-TAPP/TCPP(Mn) NPs synthesized by amino-porphyrins (TAPP) doping can not only construct PET/MR bimodal probes but also improve the T1 relaxivity (up to 456%). Moreover, T1 relaxivity can be adjusted by altering the molar ratio of TAPP/TCPP(Mn) and the concentration of F127. However, a similar increase in T1 relaxivity was not observed in the F127-TCPP/TCPP(Mn) NPs, which were synthesized using carboxy-porphyrins (TCPP) doping. In a breast cancer lymph node metastasis mice model, subcutaneous injection of 68Ga-F127-TAPP/TCPP(Mn) NPs through the hind foot pad, the normal lymph nodes and metastatic lymph nodes were successfully distinguished based on the difference of PET standard uptake values and MR signal intensities. Furthermore, the dark brown F127-TAPP/TCPP(Mn) NPs demonstrated the potential for staining and mapping lymph nodes. This study provides valuable insights into developing and applying PET/MR probes for lymph node metastasis imaging.

Characteristics of SARS-CoV-2 Omicron BA.5 variants in Shanghai after ending the zero-COVID policy in December 2022: a clinical and genomic analysis.

Introduction: An unprecedented surge of Omicron infections appeared nationwide in China in December 2022 after the adjustment of the COVID-19 response policy. Here, we report the clinical and genomic characteristics of SARS-CoV-2 infections among children in Shanghai during this outbreak. Methods: A total of 64 children with symptomatic COVID-19 were enrolled. SARS-CoV-2 whole genome sequences were obtained using next-generation sequencing (NGS) technology. Patient demographics and clinical characteristics were compared between variants. Phylogenetic tree, mutation spectrum, and the impact of unique mutations on SARS-CoV-2 proteins were analysed in silico. Results: The genomic monitoring revealed that the emerging BA.5.2.48 and BF.7.14 were the dominant variants. The BA.5.2.48 infections were more frequently observed to experience vomiting/diarrhea and less frequently present cough compared to the BF.7.14 infections among patients without comorbidities in the study. The high-frequency unique non-synonymous mutations were present in BA.5.2.48 (N:Q241K) and BF.7.14 (nsp2:V94L, nsp12:L247F, S:C1243F, ORF7a:H47Y) with respect to their parental lineages. Of these mutations, S:C1243F, nsp12:L247F, and ORF7a:H47Y protein were predicted to have a deleterious effect on the protein function. Besides, nsp2:V94L and nsp12:L247F were predicted to destabilize the proteins. Discussion: Further in vitro to in vivo studies are needed to verify the role of these specific mutations in viral fitness. In addition, continuous genomic monitoring and clinical manifestation assessments of the emerging variants will still be crucial for the effective responses to the ongoing COVID-19 pandemic.

Lipophilic Group-Modified Manganese(II)-Based Contrast Agents for Vascular and Hepatobiliary Magnetic Resonance Imaging.

Effective vascular and hepatic enhancement and better safety are the key drivers for exploring gadolinium-free hepatobiliary contrast agents. Herein, a facile strategy proposes that the high lipophilicity may be favorable to enhancing sequentially vascular and hepatobiliary signal intensity based on the structure-activity relationship that both hepatic uptake and interaction with serum albumins partly depend on lipophilicity. Therefore, 11 newly synthesized derivatives of manganese o-phenylenediamine-N,N,N',N'-tetraacetic acid (MnLs) were evaluated as vascular and hepatobiliary agents. The maximum signal intensities of the heart, liver, and kidneys were strongly correlated with log P, a key indicator of lipophilicity. The most lipophilic agent, MnL6, showed favorable relaxivity when binding with serum albumin, good vascular enhancement, rapid excretion, and reliable hepatobiliary phases comparable to a classic hepatobiliary agent, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) for in vivo liver tumor imaging. Inhibition experiments confirmed the hepatic targeting of MnL6 is mediated by organic anion-transporting polypeptides.

Tailoring Zinc Ferrite Nanoparticle Surface Coating for Macrophage-Affinity Magnetic Resonance Imaging of Atherosclerosis.

Atherosclerosis is a chronic inflammatory disease characterized by the formation of atherosclerotic plaques, while macrophages as key players in plaque progression and destabilization are promising targets for atherosclerotic plaque imaging. Contrast-enhanced magnetic resonance imaging (CE-MRI) has emerged as a powerful noninvasive imaging technique for the evaluation of atherosclerotic plaques within arterial walls. However, the visualization of macrophages within atherosclerotic plaques presents considerable challenges due to the intricate pathophysiology of the disease and the dynamic behavior of these cells. Biocompatible ferrite nanoparticles with diverse surface ligands possess the potential to exhibit distinct relaxivity and cellular affinity, enabling improved imaging capabilities for macrophages in atherosclerosis. In this work, we report macrophage-affinity nanoparticles for magnetic resonance imaging (MRI) of atherosclerosis via tailoring nanoparticle surface coating. The ultrasmall zinc ferrite nanoparticles (Zn0.4Fe2.6O4) as T1 contrast agents were synthesized and modified with dopamine, 3,4-dihydroxyhydrocinnamic acid, and phosphorylated polyethylene glycol to adjust their surface charges to be positively, negatively, and neutrally charged, respectively. In vitro MRI evaluation shows that the T1 relaxivity for different surface charged Zn0.4Fe2.6O4 nanoparticles was three higher than that of the clinically used Gd-DTPA. Furthermore, in vivo atherosclerotic plaque MR imaging indicates that positively charged Zn0.4Fe2.6O4 showed superior MRI efficacy on carotid atherosclerosis than the other two, which is ascribed to high affinity to macrophages of positively charged nanoparticles. This work provides improved diagnostic capability and a better understanding of the molecular imaging of atherosclerosis.

Chiral Osmium(II)/Salox Species Enabled Enantioselective γ-C(sp3)-H Amidation: Integrated Experimental and Computational Validation For the Ligand Design and Reaction Development.

Herein, multiple types of chiral Os(II) complexes have been designed to address the appealing yet challenging asymmetric C(sp3)-H functionalization, among which the Os(II)/Salox species is found to be the most efficient for precise stereocontrol in realizing the asymmetric C(sp3)-H amidation. As exemplified by the enantioenriched pyrrolidinone synthesis, such tailored Os(II)/Salox catalyst efficiently enables an intramolecular site-/enantioselective C(sp3)-H amidation in the γ-position of dioxazolone substrates, in which benzyl, propargyl and allyl groups bearing various substituted forms are well compatible, affording the corresponding chiral γ-lactam products with good er values (up to 99 : 1) and diverse functionality (>35 examples). The unique performance advantage of the developed chiral Os(II)/Salox system in terms of the catalytic energy profile and the chiral induction has been further clarified by integrated experimental and computational studies.

Ndfip1 protected dopaminergic neurons via regulating mitochondrial function and ferroptosis in Parkinson's disease.

Increasing evidence has shown that mitochondrial dysfunction and iron accumulation contribute to the pathogenesis of Parkinson's disease (PD). Nedd4 family interacting protein 1 (Ndfip1) is an adaptor protein of the Nedd4 E3 ubiquitin ligases. We have previously reported that Ndfip1 showed a neuroprotective effect in cell models of PD. However, whether Ndfip1 could protect dopaminergic neurons in PD animal models in vivo and the possible mechanisms are not known. Here, our results showed that the expression of Ndfip1 decreased in the substantia nigra (SN) of 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced PD mouse model. Overexpression of Ndfip1 could improve MPTP-induced motor dysfunction significantly and antagonize the loss of dopaminergic neurons in the SN of MPTP-induced mice. Further study showed that overexpression of Ndfip1 might protect against MPTP-induced neurotoxicity through regulation of voltage-dependent anion-selective channel (VDAC). In addition, we observed the downregulation of Ndfip1 and upregulation of VDAC1/2 in 1-methyl-4-phenylpyridinium ion (MPP+)-induced SH-SY5Y cells. Furthermore, high expression of Ndfip1 in SH-SY5Y cells inhibited MPP+-induced increase of VDAC1/2 and restored MPP+-induced mitochondrial dysfunction. Furthermore, Ndfip1 prevented MPP+-induced increase in the expression of long-chain acyl-CoA synthetase 4 (ACSL4), suggesting the possible role of Ndfip1 in regulating ferroptosis. Our results provide new evidence for the neuroprotective effect of Ndfip1 on dopaminergic neurons in PD animal models and provide promising targets for the treatment of iron-related diseases, including PD.

Diabetic foot wound ulcers management by vacuum sealing drainage: A meta-analysis.

The meta-analysis aimed to assess and compare diabetic foot wound ulcer management by vacuum sealing drainage. Using dichotomous or contentious random- or fixed-effects models, the outcomes of this meta-analysis were examined, and the odds ratio (OR) and the mean difference (MD) with 95% confidence intervals (CIs) were computed. Twenty-three examinations from 2000 to 2023 were enrolled for the present meta-analysis, including 1928 individuals with diabetic foot ulcers. Vacuum sealing drainage had significantly lower wound healing (OR, 2.35; 95% CI, 1.79-3.08, p < 0.001), lower duration of therapy (MD, -6.19; 95% CI, -10.06 to -2.32, p = 0.002), higher wound size reduction (MD, 4.22; 95% CI, 0.87-7.56, p = 0.01) and lower complication (OR, 0.32; 95% CI, 0.13-0.80, p = 0.01) compared with standard therapy in patients with diabetic foot ulcers. The examined data revealed that vacuum sealing drainage had significantly lower wound healing, duration of therapy and complication rates, as well as higher wound size reduction, compared with standard therapy in patients with diabetic foot ulcers. Yet, attention should be paid to its values since most of the selected examinations had a low sample size.

Reproductive Profile of Neuronal Androgen Receptor Knockout Female Mice With a Low Dose of DHT.

Hyperandrogenism and polycystic ovarian syndrome result from the imbalance or increase of androgen levels in females. Androgen receptor (AR) mediates the effects of androgens, and this study examines whether neuronal AR plays a role in reproduction under normal and increased androgen conditions in female mice. The neuron-specific AR knockout (KO) mouse (SynARKO) was generated from a female mouse (synapsin promoter driven Cre) and a male mouse (Ar fl/y). Puberty onset and the levels of reproductive hormones such as LH, FSH, testosterone, and estradiol were comparable between the control and the SynARKO mice. There were no differences in cyclicity and fertility between the control and SynARKO mice, with similar impairment in both groups on DHT treatment. Neuronal AR KO, as in this SynARKO mouse model, did not alleviate the infertility associated with DHT treatment. These studies suggest that neuronal AR KO neither altered reproductive function under physiological androgen levels, nor restored fertility under hyperandrogenic conditions.

Glucosylation endows nanoparticles with TLR4 agonist capability to trigger macrophage polarization and augment antitumor immunity.

Carbohydrates have emerged as promising candidates for immunomodulation, however, how to present them to immune cells and achieve potent immunostimulatory efficacy remains challenging. Here, we proposed and established an effective way of designing unique glyconanoparticles that can amplify macrophage-mediated immune responses through structural mimicry and multiple stimulation. We demonstrate that surface modification with glucose can greatly augment the immunostimulatory efficacy of nanoparticles, comparing to mannose and galactose. In vitro studies show that glucosylation improved the pro-inflammatory efficacy of iron oxide nanoparticles (IONPs) by up to 300-fold, with the immunostimulatory activity of glucosylated IONPs even surpassing that of LPS under certain conditions. In vivo investigation show that glucosylated IONPs elicited increased antitumor immunity and achieved favorable therapeutic outcomes in multiple murine tumor models. Mechanistically, we proposed that glucosylation potentiated the immunostimulatory effect of IONPs by amplifying toll-like receptors 4 (TLR4) activation. Specifically, glucosylated IONPs directly interacted with the TLR4-MD2 complex, resulting in M1 macrophage polarization and enhanced antitumor immunity via activation of NF-κB, MAPK, and STAT1 signaling pathways. Our work provides a simple modification strategy to endow nanoparticles with potent TLR4 agonist effects, which may shed new light on the development of artificial immune modulators for cancer immunotherapy.

Bipolar Rashba Semiconductors: A Class of Nonmagnetic Materials for Electrical Spin Manipulation.

The realization of the electrical control of spin is highly desirable. One promising approach is by regulating the Rashba spin-orbit coupling effect of materials through external electric fields. However, this method requires materials to possess either a high electric field response and a large Rashba constant or the simultaneous presence of Rashba splitting and ferroelectric polarization. These stringent requirements result in a scarcity of suitable materials. In order to surpass these limitations and exploit a new prospect for spin manipulation via the Rashba effect, a conceptual class of materials named bipolar Rashba semiconductors (BRS) is proposed, whose valence band and conduction band possess opposite spin texture directions when approaching the Fermi level. The unique electronic structure of BRS makes it feasible to reverse the spin precession by simply applying a gate voltage. The existence of BRS is confirmed through first-principles calculations on the two-dimensional (2D) material AlBiS3.

The inter-link of ageing, cancer and immunity: findings from real-world retrospective study.

BACKGROUND: Although the concept of declined immune function associated with cancer has been accepted extensively, real-world clinical studies focusing on analysis of the peripheral blood immune changes underlying ageing, immunity and cancer are scarce. METHODS: In this case-control study, we retrospectively analysed 1375 cancer patients and enrolled 275 age and gender matched healthy individuals. Flow cytometry was conducted to assess the immune changes. Further analysis was examined by SPSS 17.0 and GraphPad Prism 9 software. RESULTS: Cancer patients showed obviously decreased CD3+ T, CD3+CD4+ Th, CD3+CD8+ CTL, CD19+ B, CD16+CD56+ NK cell counts and lower percentage of PD-1 (programmed cell death protein-1, PD-1) positive cells than healthy control (P < 0.0001). For cancer patients, the reference range of circulating percentage of PD-1+CD45+ cells, PD-1+CD3+ T cells, PD-1+CD3+CD4+ Th cells and PD-1+CD3+CD8+ CTL (Cytotoxic T Lymphocyte, CTL) were 11.2% (95% CI 10.8%-11.6%), 15.5% (95% CI 14.7%-16.0%), 15.4% (95% CI 14.9%-16.0%) and 14.5% (95% CI 14.0%-15.5%), respectively. Moreover, the reduction of CD3+ T, CD3+CD4+ Th, CD3+CD8+ CTL, CD19+ B cell counts accompanied with age and stage advancing (P < 0.05). CD16+CD56+ NK cells decreased with stage, but elevated in aged and male cancer patients (P < 0.05). Additionally, the percentage of PD-1 positive cells varied across cancer types, raised with age and stage. Head and neck, pancreatic, gynaecological and lung demonstrated a higher level of the percentage of PD-1 positive cells than melanoma, prostate, and breast cancer (P < 0.05). CONCLUSIONS: This study provides the reference range of the percentage of PD-1 positive cells on peripheral blood, confirms the decreased immune cells and a series of immune changes accompanying with cancer, expands our real world evidence to better understand the interactions of ageing, cancer and immunity. Moreover, the circulating percentage of PD-1 positive cells shows similar tumor type distribution with tumor mutational burden (TMB), supports that it maybe a potential predictive biomarker for immune checkpoint inhibitor therapy.

PEGylated Amphiphilic Gd-DOTA Backboned-Bound Branched Polymers as Magnetic Resonance Imaging Contrast Agents.

MRI contrast agents with high kinetic stability and relaxivity are the key objectives in the field. We previously reported that Gd-DOTA backboned-bound branched polymers possess high kinetic stability and significantly increased T1 relaxivity than traditional branched polymer contrast agents. In this work, non-PEGylated and PEGylated amphiphilic Gd-DOTA backboned-bound branched polymers [P(GdDOTA-C6), P(GdDOTA-C10), mPEG-P(GdDOTA-C6), and mPEG-P(GdDOTA-C10)] were obtained by sequential introduction of rigid carbon chains (1,6-hexamethylenediamine or 1,10-diaminodecane) and mPEG into the structure of Gd-DOTA backboned-bound branched polymers. It is found that the introduction of both rigid carbon chains, especially the longer one, and mPEG can increase the kinetic stability and T1 relaxivity of Gd-DOTA backboned-bound branched polymers. Among them, mPEG-P(GdDOTA-C10) possesses the highest kinetic stability (significantly higher than those of linear Gd-DTPA and cyclic Gd-DOTA-butrol) and T1 relaxivity (42.9 mM-1 s-1, 1.5 T), 11 times that of Gd-DOTA and 1.4 times that of previously reported Gd-DOTA backboned-bound branched polymers. In addition, mPEG-P(GdDOTA-C10) showed excellent MRA effect in cardiovascular and hepatic vessels at a dose (0.025 or 0.05 mmol Gd/kg BW) far below the clinical range (0.1-0.3 mmol Gd/kg BW). Overall, effective branched-polymer-based contrast agents can be obtained by a strategy in which rigid carbon chains and PEG were introduced into the structure of Gd-DOTA backbone-bound branched polymers, resulting in excellent kinetic stability and enhanced T1 relaxivity.

Relaxivity Enhancement of Hybrid Micelles via Modulation of Water Coordination Numbers for Magnetic Resonance Lymphography.

Considerable efforts have been made to develop nanoparticle-based magnetic resonance contrast agents (CAs) with high relaxivity. The prolonged rotational correlation time (τR) induced relaxivity enhancement is commonly recognized, while the effect of the water coordination numbers (q) on the relaxivity of nanoparticle-based CAs gets less attention. Herein, we first investigated the relationship between T1 relaxivity (r1) and q in manganese-based hybrid micellar CAs and proposed a strategy to enhance the relaxivity by increasing q. Hybrid micelles with different ratios of amphiphilic manganese complex (MnL) and DSPE-PEG2000 were prepared, whose q values were evaluated by Oxygen-17-NMR spectroscopy. Micelles with lower manganese doping density exhibit increased q and enhanced relaxivity, corroborating the conception. In vivo sentinel lymph node (SLN) imaging demonstrates that DSPE-PEG/MnL micelles could differentiate metastatic SLN from inflammatory LN. Our strategy makes it feasible for relaxivity enhancement by modulating q, providing new approaches for the structural design of high-performance hybrid micellar CAs.

Neuronal AR Regulates Glucose Homeostasis and Energy Expenditure in Lean Female Mice With Androgen Excess.

Hyperandrogenemia and polycystic ovary syndrome are a result of the imbalance of androgen levels in females. Androgen receptor (Ar) mediates the effect of androgen, and this study examines how neuronal Ar in the central nervous system mediates metabolism under normal and increased androgen conditions in female mice. The neuron-specific ARKO mouse (SynARKO) was created from female (Ar fl/wt; synapsin promoter driven Cre) and male (Ar fl/y) mice. A glucose tolerance test revealed impaired glucose tolerance that was partially alleviated in the SynARKO-dihydrotestosterone (DHT) mice compared with Con-DHT mice after 4 months of DHT treatment. Heat production and food intake was higher in Con-DHT mice than in Con-veh mice; these effects were not altered between SynARKO-veh and SynARKO-DHT mice, indicating that excess androgens may partially alter calorie intake and energy expenditure in females via the neuronal Ar. The pAkt/Akt activity was higher in the hypothalamus in Con-DHT mice than in Con-veh mice, and this effect was attenuated in SynARKO-DHT mice. Western blot studies show that markers of inflammation and microglia activation, such as NF-kB p-65 and IBA1, increased in the hypothalamus of Con-DHT mice compared with Con-veh. These studies suggest that neuronal Ar mediates the metabolic impacts of androgen excess in females.

The m6A reader MhYTP2 regulates the stability of its target mRNAs contributing to low nitrogen tolerance in apple (Malus domestica).

Studies have shown that the m6A reader primarily affects genes expression by participating in the regulation of mRNA localization, splicing, degradation, translation, and other metabolic processes. Previously, we discovered that the apple (Malus domestica) m6A reader MhYTP2 bound with and destabilized m6A-modified MdMLO19 mRNA. In addition, it enhanced the translation efficiency of m6A-modified mRNA of MdGDH1L, encoding a glutamate dehydrogenase, which confers resistance to powdery mildew. In this study, we report the function of MhYTP2 in the regulation of resistance to low nitrogen (N). The overexpression of MhYTP2 enhances the resistance of apple to low N. We show that MhYTP2 binds with and stabilizes the mRNAs of MdALN, which participates in the allantoin catabolic process and cellular response to N starvation in apple; MdPIDL, which participates in root hair elongation; MdTTG1, which is involved in the differentiation process of trichomes; and MdATG8A, which is a core participant in the regulation of autophagy. In addition, MhYTP2 accelerates the degradation of MdRHD3 mRNA, which regulates root development. RNA immunoprecipitation-seq and electrophoretic mobility shift assays show that the mRNAs of MdALN, MdATG8A, MdPIDL, MdTTG1, and MdRHD3 are the direct targets of MhYTP2. Overexpressing or knocking down the above genes in MhYTP2 overexpressing plants dismisses the function of MhYTP2 under low N, suggesting the role of MhYTP2 is dependent on those genes. Together, these results demonstrate that MhYTP2 enhances the resistance of apple to N deficiency by affecting the stability of the bound mRNAs.

The m6 A reader MhYTP2 negatively modulates apple Glomerella leaf spot resistance by binding to and degrading MdRGA2L mRNA.

Glomerella leaf spot (GLS), caused by the fungal pathogen Colletotrichum fructicola, significantly threatens apple production. Some resistances to plant disease are mediated by the accumulation of nucleotide-binding site and leucine-rich repeat (NBS-LRR) proteins that are encoded by a major class of plant disease resistance genes (R genes). However, the R genes that confer resistance to GLS in apple remain largely unclear. Malus hupehensis YT521-B homology domain-containing protein 2 (MhYTP2) was identified as an N6 -methyladenosine RNA methylation (m6 A) modified RNA reader in our previous study. However, whether MhYTP2 binds to mRNAs without m6 A RNA modifications remains unknown. In this study, we discovered that MhYTP2 exerts both m6 A-dependent and -independent functions by analysing previously obtained RNA immunoprecipitation sequencing results. The overexpression of MhYTP2 significantly reduced the resistance of apple to GLS and down-regulated the transcript levels of some R genes whose transcripts do not contain m6 A modifications. Further analysis indicated that MhYTP2 binds to and reduces the stability of MdRGA2L mRNA. MdRGA2L positively regulates resistance to GLS by activating salicylic acid signalling. Our findings revealed that MhYTP2 plays an essential role in the regulation of resistance to GLS and identified a promising R gene, MdRGA2L, for use in developing apple cultivars with GLS resistance.