The association between the triglyceride-glucose index and bone turnover markers in osteoporotic fractures patients aged 50 and above who are hospitalized for surgical intervention: a retrospective cross-sectional study.

Objective: To evaluate the correlation between the triglyceride-glucose (TyG) index and bone turnover markers (BTMs) in osteoporotic fractures (OPFs) patients hospitalized for surgical intervention. Methods: A retrospective cross-sectional study was conducted on 3558 OPFs patients hospitalized for surgical intervention between January 2017 and July 2022. The study obtained baseline values for various biomarkers and covariates, including fasting blood glucose, ß-C-terminal telopeptide of type I collagen (ß-CTX), procollagen type 1 N-terminal propeptide (P1NP), triglycerides, age, sex, body mass index, smoking, drinking, low-density lipoprotein, high-density lipoprotein, aspartate aminotransferase, uric acid, the score of American society of anesthesiologists, homocysteine, parathyroid hormone, apolipoprotein B, apolipoprotein A, magnesium, phosphorus and calcium. Multiple linear regression, curve fitting, threshold effects, and subgroup analyses were also applied. Results: After adjusting for covariates in the regression analysis, the results revealed a negative correlation between ß-CTX and P1NP levels and the baseline TyG index. Specifically, a one-unit increase in the TyG index was associated with a reduction in ß-CTX levels of -0.06 (95% CI: -0.10, -0.01; P-value = 0.012) and a reduction in P1NP levels of -4.70 (95% CI: -9.30, -0.09; P-value = 0.046). Additionally, the inflection points for the nonlinear correlation between the TyG index and ß-CTX and P1NP were found to be K = 6.31 and K = 6.63, respectively. Conclusion: The study demonstrated a negative, non-linear relationship among the TyG index, ß-CTX and P1NP in OPFs patients hospitalized for surgical intervention. These findings suggest that elevated TyG index levels may adversely affect bone turnover, potentially contributing to the progression of OP.

Substrate preference, RNA binding and active site versatility of Stenotrophomonas maltophilia nuclease SmNuc1, explained by a structural study.

Nucleases of the S1/P1 family have important applications in biotechnology and molecular biology. We have performed structural analyses of SmNuc1 nuclease from Stenotrophomonas maltophilia, including RNA cleavage product binding and mutagenesis in a newly discovered flexible Arg74-motif, involved in substrate binding and product release and likely contributing to the high catalytic rate. The Arg74Gln mutation shifts substrate preference towards RNA. Purine nucleotide binding differs compared to pyrimidines, confirming the plasticity of the active site. The enzyme-product interactions indicate a gradual, stepwise product release. The activity of SmNuc1 towards c-di-GMP in crystal resulted in a distinguished complex with the emerging product 5'-GMP. This enzyme from an opportunistic pathogen relies on specific architecture enabling high performance under broad conditions, attractive for biotechnologies.

Purines and purinergic receptors in primary tumors of the central nervous system.

Purine nucleotides and nucleosides play critical roles in various pathological conditions, including tumor cell growth. Adenosine triphosphate (ATP) activates pro-tumor receptors, while adenosine (ADO) is a potent immunosuppressant and modulator of cell growth. This study aims to analyze the purinergic actions of ATP and its metabolites, associated enzymes, and P1 or P2 class receptors in primary central nervous system tumors. Additionally, we sought to correlate the levels of nucleosides and the density of P1, P2X, and P2Y receptors in cells with tumor progression. The results indicate that purinergic signaling depends on the receptor concentration and signaling molecules specific to each cell type, tissue, and tumor histology. The purinergic system may function as either a tumor-promoting agent or an antitumor factor, depending on the microenvironmental conditions and the concentrations of receptors and their respective activators. Notably, ATP emerges as the most significant extracellular signal, capable of being converted into other cellular stimulators pertinent to neoplasms, such as adenosine diphosphate, adenosine monophosphate, adenosine, and inosine. Consequently, a cascade of responses to these stimuli promotes tumor development, cell division, and metastasis. Purine nucleotides in central nervous system tumors are pivotal in cellular responses in glioblastoma multiforme, vestibular schwannoma, medulloblastoma, adenomas, gliomas, meningiomas, and pineal tumors. These findings hold the potential for developing novel therapeutic strategies and aiding in therapeutic management.

Selenoprotein-p and insulin resistance in children and adolescents with obesity.

BACKGROUND: Insulin resistance and obesity present significant challenges in pediatric populations. Selenoprotein P1 (SEPP1) serves as a biomarker for assessing selenium levels in the body. While its association with metabolic syndrome is established in adults, its relevance in children remains underexplored. AIM: To ascertain SEPP1 blood levels in children and adolescents diagnosed with obesity and to assess its correlation with insulin resistance and adiposity indices. METHODS: 170 children participated in this study, including 85 diagnosed with obesity and an equal number of healthy counterparts matched for age and sex. Each participant underwent a comprehensive medical evaluation, encompassing a detailed medical history, clinical examination, and anthropometric measurements like waist circumference and waist-to-height ratio. Furthermore, routine blood tests were conducted, including serum SEPP1, visceral adiposity index (VAI), and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) level. RESULTS: Our findings revealed significantly lower serum SEPP1 levels in children with obesity compared to their healthy peers. Moreover, notable negative correlations were observed between serum SEPP1 levels and body mass index, VAI, and HOMA-IR. CONCLUSION: The study suggests that SEPP1 could serve as a valuable predictor for insulin resistance among children and adolescents diagnosed with obesity. This highlights the potential utility of SEPP1 in pediatric metabolic health assessment and warrants further investigation.

Myofiber-specific FoxP1 knockout protects against pancreatic cancer-induced muscle wasting in male but not female mice.

Cancer cachexia affects up to 80% of cancer patients and results in reduced quality of life and survival. We previously demonstrated that the transcriptional repressor Forkhead box P1 (FoxP1) is upregulated in skeletal muscle of cachectic mice and people with cancer, and when overexpressed in skeletal muscle is sufficient to induce pathological features characteristic of cachexia. However, the role of myofiber-derived FoxP1 in both normal muscle physiology and cancer-induced muscle wasting remains largely unexplored. To address this gap, we generated a conditional mouse line with myofiber-specific ablation of FoxP1 (FoxP1SkmKO) and found that in cancer-free mice, deletion of FoxP1 in skeletal myofibers resulted in increased myofiber size in both males and females, with a significant increase in muscle mass in males. In response to murine KPC pancreatic tumor burden, we found that myofiber-derived FoxP1 is required for cancer-induced muscle wasting and diaphragm muscle weakness in male mice. In summary, our findings identify myofiber-specific FoxP1 as a negative regulator of skeletal muscle with sex-specific differences in the context of cancer.

Establishment of Reference Intervals for Bone Turnover Biomarkers in Healthy Populations in Northern China.

Aim: This study was intended to establish the reference intervals of bone turnover markers (BTMs) for healthy populations. Methods: According to the Clinical Laboratory Standards Institute (CLSI) EP28-A3c, we recruited 774 healthy Chinese and investigated their clinical characteristics and relationships among gender, age, season and BTMs. The reference intervals of BTMs for healthy populations in Hebei of China were established through defining the central 95% range of all observations. Results: We found that gender were associated with 25(OH)D, OC, ß-CTX, and P1NP (P < 0.05), but not PTH1-84 (P=0.138). All serum BTMs showed differences among different age groups (P < 0.01). The level of 25 (OH) D in winter showed statistical differences with spring, summer, and autumn (P<0.05). The OC level showed statistical difference between summer and winter (P=0.000). The P1NP levels showed statistical difference between spring and winter (P=0.019), summer and winter (P=0.000), and summer and autumn (P=0.012), respectively. The PTH1-84 levels in winter showed statistical differences with spring, and summer (all P=0.000), while there was no statistically significant difference in ß- CTX levels between seasons. Conclusion: We have established the reference intervals of several BTMs for healthy individuals in Hebei of China, which have statistical significance across different age groups and genders, and there are also significant differences between different seasons. Therefore, the Chinese medical laboratories in different locations should group individuals according to gender and age groups in different seasons, and establish corresponding biological reference intervals.

Galangin alleviated Doxorubicin-induced cardiotoxicity by inhibiting ferroptosis through GSTP1/JNK pathway.

BACKGROUND: Doxorubicin (DOX) is a potent anticancer medication, but its significant cardiotoxicity poses a challenge in clinical practice. Galangin (Gal), a flavonoid compound with diverse pharmacological activities, has shown potential in exerting cardioprotective effects. However, the related molecular mechanism has not been fully elucidated. PURPOSE: Combined with bioinformatics and experimental verification methods to investigate Gal's potential role and underlying mechanisms in mitigating DOX-induced cardiotoxicity (DIC). METHODS: C57BL/6 mice received a single dose of DOX via intraperitoneal injection 4 days before the end of the gavage period with Gal. Myocardial injury was evaluated using echocardiography, myocardial injury biomarkers, Sirius Red and H&E staining. H9c2 cells were stimulated with DOX to mimic DIC in vitro. The potential therapeutic target of Gal was identified through network pharmacology, molecular docking and cellular thermal shift assay (CETSA), complemented by an in-depth exploration of the GSTP1/JNK signaling pathway using immunofluorescence. Subsequently, the GSTP1 inhibitor Ezatiostat (Eza) substantiated the signaling pathway. RESULTS: Gal administration considerably raised DOX-inhibited the left ventricular ejection fractions (LVEF), reduced levels of myocardial injury markers (c-TnI, c-TnT, CKMB, LDH, and AST), and alleviated DOX-induced myocardial histopathological injury and fibrosis in mice, thereby improving cardiac dysfunction. The ferroptosis induced by DOX was inhibited by Gal treatment. Gal remarkably ameliorated the DOX-induced lipid peroxidation, accumulation of iron and Ptgs2 expression both in H9c2 cells and cardiac tissue. Furthermore, Gal effectively rescued the DOX-inhibited crucial regulators of ferroptosis such as Gpx4, Nrf2, Fpn, and Slc7a11. The mechanistic investigations revealed that Glutathione S-transferase P1 (GSTP1) may be a potential target for Gal in attenuating DIC. Gal act on GSTP1 by stimulating its expression, thereby enhancing the interaction between GSTP1 and c-Jun N-terminal kinase (JNK), leading to the deactivation of JNK/c-Jun pathway. Furthermore, interference of GSTP1 with inhibitor Eza abrogated the cardioprotective and anti-ferroptotic effects of Gal, as evidenced by decreased cell viability, reduced expression of GSTP1 and Gpx4, elevated MDA levels, and promoted phosphorylation of JNK and c-Jun compared with Gal treatment. CONCLUSION: Gal could inhibit ferroptosis and protect against DIC through regulating the GSTP1/JNK pathway. Our research has identified a novel pathway through which Gal regulates DIC, providing valuable insights into the potential therapeutic efficacy of Gal in mitigating cardiotoxic effects.

Electrically evoked late latency response using single electrode stimulation and its relation to speech perception among paediatric cochlear implant users.

Introduction: Aided auditory late latency response (LLR) serves as an objective tool for evaluating auditory cortical maturation following cochlear implantation in children. While aided LLR is commonly measured using sound-field acoustic stimulation, recording electrically evoked LLR (eLLR) offer distinct advantages, such as improved stimulus control and the capability for single electrode stimulation. Hence, the study aimed to compare eLLR responses with single electrode stimulation in the apical, middle, and basal regions and to evaluate their relationship with speech perception in paediatric cochlear implant (CI) recipients. Method: eLLR responses with single electrode stimulation were measured in 27 paediatric unilateral CI users with an active recording electrode placed at Cz. The stimuli consisted of 36 msec biphasic pulse trains presented across three electrode sites (apical-E20, middle-E11, and basal-E03). eLLR responses were compared across these electrode sites, and the relationship between speech recognition scores in quiet and age at implantation with eLLR components was evaluated. Results: eLLR responses were detected in 77 out of 81 tested electrodes of all participants combined (27 for apical, 26 for middle, and 24 for basal stimulation). There were no significant differences in P1, N1 latencies and P1 amplitude across electrode site. However, significantly larger N1 and P1-N1 amplitudes were observed for apical stimulations compared to basal stimulations. No differences in N1 amplitude were found between middle and apical stimulations, and the P1-N1 amplitude was significantly larger for middle compared to basal electrode stimulation, with no difference between the apical and middle electrodes stimulation. A moderate positive correlation was present between speech recognition scores in quiet and both N1, P1-N1 amplitudes for apical stimulation. Age at implantation was negatively correlated with N1 amplitude for the apical and P1-N1 amplitude for basal stimulation. Discussion: eLLR responses could be elicited in majority of paediatric CI users across electrode sites. Variations in eLLR responses across electrode sites suggest disparities in auditory cortical maturation. The findings underscore the significance of the N1 biomarker in evaluating higher-order auditory cortical development. Therefore, utilizing eLLR with single electrode stimulation may serve as a valuable tool for assessing post-cochlear implantation maturational changes in paediatric populations.

You're Beautiful When You Smile: Event-Related Brain Potential (ERP) Evidence of Early Opposite-Gender Bias in Happy Faces.

Studies of social cognition have shown gender differences regarding human face processing. One interesting finding is the enhanced processing of opposite-gender faces at different time stages, as revealed by event-related brain potentials. Crucially, from an evolutionary perspective, such a bias might interact with the emotional expression of the face. To investigate this, 100 participants (50 female, 50 male) completed an expression-detection task while their EEG was recorded. In three blocks, fearful, happy and neutral faces (female and male) were randomly presented, with participants instructed to respond to only one predefined target expression level in each block. Using linear mixed models, we observed both faster reaction times as well as larger P1 and late positive potential (LPP) amplitudes for women compared to men, supporting a generally greater female interest in faces. Highly interestingly, the analysis revealed an opposite-gender bias at P1 for happy target faces. This suggests that participants' attentional templates may include more opposite-gender facial features when selectively attending to happy faces. While N170 was influenced by neither the face nor the participant gender, LPP was modulated by the face gender and specific combinations of the target status, face gender and expression, which is interpreted in the context of gender-emotion stereotypes. Future research should further investigate this expression and attention dependency of early opposite-gender biases.

Bone Turnover Markers during Growth Hormone Therapy for Short Stature Children Born Small for Gestational Age.

Growth hormone therapy (GHT) can improve growth velocity and final height, but can also accelerate the process of bone growth, which is related to structural bone modeling in both formation and resorption. This study evaluated the capacity of bone turnover markers to predict early growth response to one year of GHT in short stature children born small for gestational age (SGA). This study included 25 prepubertal children born SGA. We estimated P1NP (N-terminal procollagen type 1), CTX (C-terminal telopeptide of collagen type 1), P3NP (N-terminal procollagen type 3), NT-pro-CNP (amino-terminal C-type natriuretic peptide) and Ca-P metabolism using standard ECLIA (electrochemiluminescence), RIA (radioimmunoassay), and ELISA (enzyme-linked immunosorbent assay) methods. A statistically significant increase in bone resorption markers (CTX) was found at both 6 and 12 months. P1NP bone markers were increased at 6 months and after 12 months of therapy. The P3NP marker for collagen synthesis also increased after 12 months of therapy. We obtained significant increases in phosphorus levels at 6 and 12 months, and similar ALP (alkaline phosphatase) increases. We found a significant correlation between height (cm) and CTX after 6-12 months, as well as a P1NP/height (SD) correlation after 12 months. Calcium levels significantly correlated with height (SD) after 12 months. We found strong reactions of bone resorption and bone formation markers during growth hormone therapy, which may determine their selection as predictors of GHT outcome in children born SGA. However, the issue requires further research.

Pro-Osteogenic Effect of the Nutraceutical BlastiMin Complex® in Women with Osteoporosis or Osteopenia: An Open Intervention Clinical Trial.

Osteoporosis is a chronic disease that affects millions of patients worldwide and is characterized by low bone mineral density (BMD) and increased risk of fractures. Notably, natural molecules can increase BMD and exert pro-osteogenic effects. Noteworthily, the nutraceutical BlastiMin Complex® (Mivell, Italy, European Patent Application EP4205733A1) can induce differentiation of human bone marrow mesenchymal stem cells (BM-MSCs) in osteoblasts and can exert in vitro pro-osteogenic and anti-inflammatory effects. Thus, the purpose of this study was to verify the effects of BlastiMin Complex® on bone turnover markers (BTMs) and BMD in patients with senile and postmenopausal osteopenia or osteoporosis. The efficacy of BlastiMin Complex® on BTMs in serum was evaluated through biochemical assays. BMD values were analyzed by dual-energy X-ray absorptiometry (DXA) and Radiofrequency Echographic Multi Spectrometry (R.E.M.S.) techniques, and the SNPs with a role in osteoporosis development were evaluated by PCR. Clinical data obtained after 12 months of treatment showed an increase in bone turnover index, a decrease in C-reactive protein levels, and a remarkable increase in P1NP levels, indicating the induction of osteoblast proliferation and activity in the cohort of 100% female patients recruited for the study. These findings show that the nutraceutical BlastiMin Complex® could be used as an adjuvant in combination with synthetic drugs for the treatment of osteoporosis pathology.

Predictability modulates the early neural coding of spatially unattended fearful faces.

In this study, we assessed whether predictability affected the early processing of facial expressions. To achieve this, we measured lateralised early- and mid-latency event-related potentials associated with visual processing. Twenty-two participants were shown pairs of bilaterally presented fearful, happy, angry, or scrambled faces. Participants were required to identify angry faces on a spatially attended side whilst ignoring happy, fearful, and scrambled faces. Each block began with the word HAPPY or FEARFUL which informed participants the probability at which these faces would appear. Attention effects were found for the lateralised P1, suggesting that emotions do not modulate the P1 differentially, nor do predictions relating to emotions. Pairwise comparisons demonstrated that, when spatially unattended, unpredicted fearful faces produced larger lateralised N170 amplitudes compared to predicted fearful faces and unpredicted happy faces. Finally, attention towards faces increased lateralised EPN amplitudes, as did both fearful expressions and low predictability. Thus, we demonstrate that the N170 and EPN are sensitive to top-down predictions relating to facial expressions and that low predictability appears to specifically affect the early encoding of fearful faces when unattended, possibly to initiate attentional capture.

Overview of the role of purinergic signaling and insights into its role in cancer therapy.

Innovation of cancer therapy has received a dramatic acceleration over the last fifteen years thanks to the introduction of the novel immune checkpoint inhibitors (ICI). On the other hand, the conspicuous scientific knowledge accumulated in purinergic signaling since the early seventies is finally being transferred to the clinic. Several Phase I/II clinical trials are currently underway to investigate the effect of drugs interfering with purinergic signaling as stand-alone or combination therapy in cancer. This is supporting the novel concept of "purinergic immune checkpoint" (PIC) in cancer therapy. In the present review we will address a) the basic pharmacology and cell biology of the purinergic system; b) principles of its pathophysiology in human diseases; c) implications for cell death, cell proliferation and cancer; d) novel molecular tools to investigate nucleotide homeostasis in the extracellular environment; e) recent developments in the pharmacology of P1, P2 receptors and related ecto-enzymes; f) P1 and P2 ligands as novel diagnostic tools; g) current issues in PIC-based anti-cancer therapy. This review will provide an appraisal of the current status of purinergic signaling in cancer and will help identify future avenues of development.

Neural Correlates of the Attentional Bias Towards Subliminal Pornographic Cues in Individuals with Tendencies Toward Problematic Pornography Use: An ERP Study Using a Dot-Probe Task.

Attentional bias toward addiction-related stimuli has been implicated in the development and maintenance of addiction disorders. Several previous studies have reported an attentional bias toward pornographic cues in individuals with problematic pornography use (PPU). Since attentional bias can occur without conscious awareness, the purpose of this study was to use electroencephalography to examine whether individuals with a high tendency for PPU exhibit attentional bias at the level of the preconscious processing. Event-related potentials (ERPs) were recorded while male participants with high (n = 24) and low (n = 23) levels of subclinical PPU performed a masked version of the dot-probe task measuring attentional bias toward subliminally presented pornographic stimuli. Behavioral data revealed that participants from both groups with high and low tendencies for PPU reacted faster to probes replacing pornographic images than to probes replacing neutral images. ERPs revealed that individuals with a high tendency for PPU exhibited larger probe-locked P1 amplitudes following masked pornographic images (valid condition) compared with masked neutral images (invalid condition). Additionally, PPU symptom severity correlated positively with the P1 amplitude difference between valid and invalid conditions. These results highlight the automaticity of attentional capture by pornographic stimuli and support the hypothesis of an addiction-related attentional bias during preconscious processes. The implication of these findings for understanding the clinical phenomenon of out-of-control addictive behavior are discussed.

Water-medicated specifically targeting the S1 pockets among serine proteases using an arginine analogue.

Because of the high similarity in structure and sequence, it is challenging to distinguish the S1 pocket among serine proteases, primarily due to the only variability at residue 190 (A190 and S190). Peptide or protein-based inhibitors typically target the negatively charged S1 pocket using lysine or arginine as the P1 residue, yet neither discriminates between the two S1 pocket variants. This study introduces two arginine analogues, L-4-guanidinophenylalanine (12) and L-3-(N-amidino-4-piperidyl)alanine (16), as novel P1 residues in peptide inhibitors. 16 notably enhances affinities across all tested proteases, whereas 12 specifically improved affinities towards proteases possessing S190 in the S1 pocket. By crystallography and molecular dynamics simulations, we discovered a novel mechanism involving a water exchange channel at the bottom of the S1 pocket, modulated by the variation of residue 190. Additionally, the specificity of 12 towards the S190-presenting S1 pocket is dependent on this water channel. This study not only introduces novel P1 residues to engineer inhibitory potency and specificity of peptide inhibitors targeting serine proteases, but also unveils a water-mediated molecular mechanism of targeting serine proteases.

An outbreak of Mycoplasma pneumoniae in children after the COVID-19 pandemic, Shanghai, China, 2023.

Background: During the coronavirus disease 2019 (COVID-19) pandemic, the infection of Mycoplasma pneumoniae (MP) decreased significantly. At the beginning of the summer of 2023, there was an increasing trend of MP infection in China and the MP pneumonia (MPP) is surging when it comes to the school season and lasts for several months which has attracted widespread attention. Objective: This study aims to investigate the prevalent characteristics of the MP and the difference between the COVID-19 pandemic and the post in Shanghai, China. Methods: The demographic information and the results of laboratory pathogen detection from July 2021 to May 2024 were collected and analyzed to find out the prevalent characteristics of MP. Two periods, during the COVID-19 pandemic and the post-pandemic, were divided and compared. The P1 genotyping and macrolide resistance-associated gene of 23 s rRNA were detected using the remaining MP-positive samples. Results: During the COVID-19 pandemic, the prevalence of the MP has significantly decreased. Female children are more susceptible to MP infection than the male. The school-aged group (>6 years) had the highest infection rate. The rate of MP P1 genotype during post panel is higher than that during COVID-19 pandemic, which is dominant from July 2021 to May 2024, while the macrolide-resistant associated mutations (A2063G) keep high percentage during or post pandemic. Conclusion: After the COVID-19 pandemic, an outbreak of MP infection occurred from summer onwards in 2023 with children in Shanghai, China. Immunity debt and high rate of macrolide-resistance may take effects in this MP epidemic. Continuous surveillance of MP is necessary to help to alert the prevalence of MPP.

Loss-of-Imprinting of HM13 Leads to Poor Prognosis in Clear Cell Renal Cell Carcinoma.

Genomic imprinting refers to the epigenetic silencing of one of both alleles in a parent-of-origin-specific manner, particularly in genes regulating growth and development. Impaired genomic imprinting leading to the activation of the silenced allele, also called canonical loss-of-imprinting (LOI), is considered an early factor in oncogenesis. As LOI studies in clear cell renal cell carcinoma (ccRCC) are limited to IGF2, we performed a genome-wide analysis in 128 kidney normal solid tissue and 240 stage 1 ccRCC samples (TCGA RNA-seq data) to screen for canonical LOI in early oncogenesis. In ccRCC, we observed LOI (adj. p = 2.74 × 10-3) of HM13 (Histocompatibility Minor 13), a signal peptide peptidase involved in epitope generation. HM13 LOI samples featured HM13 overexpression, both compared to normal solid tissues (p = 3.00 × 10-7) and non-LOI (p = 1.27 × 10-2) samples. Upon adjustment for age and sex, HM13 expression was significantly associated with poor survival (p = 7.10 × 10-5). Moreover, HM13 overexpression consistently exacerbated with increasing tumor stage (p = 2.90 × 10-8). For IGF2, LOI was observed in normal solid tissues, but the prevalence did not increase in cancer. In conclusion, HM13 LOI is an early event in ccRCC, causing overexpression leading to poor prognosis.

Proteomic Profiling of Unannotated Microproteins in Human Placenta Reveals XRCC6P1 as a Potential Negative Regulator of Translation.

Ribosome profiling and mass spectrometry have revealed thousands of previously unannotated small and alternative open reading frames (sm/alt-ORFs) that are translated into micro/alt-proteins in mammalian cells. However, their prevalence across human tissues and biological roles remains largely undefined. The placenta is an ideal model for identifying unannotated microproteins and alt-proteins due to its considerable protein diversity that is required to sustain fetal development during pregnancy. Here, we profiled unannotated microproteins and alt-proteins in human placental tissues from preeclampsia patients or healthy individuals by proteomics, identified 52 unannotated microproteins or alt-proteins, and demonstrated that five microproteins can be translated from overexpression constructs in a heterologous cell line, although several are unstable. We further demonstrated that one microprotein, XRCC6P1, associates with translation initiation factor eIF3 and negatively regulates translation when exogenously overexpressed. Thus, we revealed a hidden sm/alt-ORF-encoded proteome in the human placenta, which may advance the mechanism studies for placenta development as well as placental disorders such as preeclampsia.

The AP-1 adaptor complex is essential for intracellular trafficking of the ORF2 capsid protein and assembly of Hepatitis E virus.

Although the Hepatitis E virus (HEV) is an emerging global health burden, little is known about its interaction with the host cell. HEV genome encodes three proteins including the ORF2 capsid protein that is produced in different forms, the ORF2i protein which is the structural component of viral particles, and the ORF2g/c proteins which are massively secreted but are not associated with infectious material. We recently demonstrated that the endocytic recycling compartment (ERC) is hijacked by HEV to serve as a viral factory. However, host determinants involved in the subcellular shuttling of viral proteins to viral factories are unknown. Here, we demonstrate that the AP-1 adaptor complex plays a pivotal role in the targeting of ORF2i protein to viral factories. This complex belongs to the family of adaptor proteins that are involved in vesicular transport between the trans-Golgi network and early/recycling endosomes. An interplay between the AP-1 complex and viral protein(s) has been described for several viral lifecycles. In the present study, we demonstrated that the ORF2i protein colocalizes and interacts with the AP-1 adaptor complex in HEV-producing or infected cells. We showed that silencing or drug-inhibition of the AP-1 complex prevents ORF2i protein localization in viral factories and reduces viral production in hepatocytes. Modeling of the ORF2i/AP-1 complex also revealed that the S domain of ORF2i likely interacts with the σ1 subunit of AP-1 complex. Hence, our study identified for the first time a host factor involved in addressing HEV proteins (i.e. ORF2i protein) to viral factories.