The correlation between lung ultrasound scores and outcomes of high-flow nasal cannula therapy in infants with severe pneumonia.

OBJECTIVE: The study aimed to explore the effectiveness of bedside lung ultrasound (LUS) combined with the PaO2/FiO2 (P/F) ratio in evaluating the outcomes of high-flow nasal cannula (HFNC) therapy in infants with severe pneumonia. METHODS: This retrospective study analyzed the clinical data of 150 infants diagnosed with severe pneumonia and treated with HFNC therapy at our hospital from January 2021 to December 2021. These patients were divided into two groups based on their treatment outcomes: the HFNC success group (n = 112) and the HFNC failure group (n = 38). LUS was utilized to evaluate the patients' lung conditions, and blood gas results were recorded for both groups upon admission and after 12 h of HFNC therapy. RESULTS: At admission, no significant differences were observed between the two groups in terms of age, gender, respiratory rate, partial pressure of oxygen, and partial pressure of carbon dioxide. However, the P/F ratios at admission and after 12 h of HFNC therapy were significantly lower in the HFNC failure group (193.08 ± 49.14, 228.63 ± 80.17, respectively) compared to the HFNC success group (248.51 ± 64.44, 288.93 ± 57.17, respectively) (p < 0.05). Likewise, LUS scores at admission and after 12 h were significantly higher in the failure group (18.42 ± 5.3, 18.03 ± 5.36, respectively) than in the success group (15.09 ± 4.66, 10.71 ± 3.78, respectively) (p < 0.05). Notably, in the success group, both P/F ratios and LUS scores showed significant improvement after 12 h of HFNC therapy, a trend not observed in the failure group. Multivariate regression analysis indicated that lower P/F ratios and higher LUS scores at admission and after 12 h were predictive of a greater risk of HFNC failure. ROC analysis demonstrated that an LUS score > 20.5 at admission predicted HFNC therapy failure with an AUC of 0.695, a sensitivity of 44.7%, and a specificity of 91.1%. A LUS score > 15.5 after 12 h of HFNC therapy had an AUC of 0.874, with 65.8% sensitivity and 89.3% specificity. An admission P/F ratio < 225.5 predicted HFNC therapy failure with an AUC of 0.739, 60.7% sensitivity, and 71.1% specificity, while a P/F ratio < 256.5 after 12 h of HFNC therapy had an AUC of 0.811, 74.1% sensitivity, and 73.7% specificity. CONCLUSION: Decreased LUS scores and increased P/F ratio demonstrate a strong correlation with successful HFNC treatment outcomes in infants with severe pneumonia. These findings may provide valuable support for clinicians in managing such cases.

VAPB-mediated ER-targeting stabilizes IRS-1 signalosomes to regulate insulin/IGF signaling.

The scaffold protein IRS-1 is an essential node in insulin/IGF signaling. It has long been recognized that the stability of IRS-1 is dependent on its endomembrane targeting. However, how IRS-1 targets the intracellular membrane, and what type of intracellular membrane is actually targeted, remains poorly understood. Here, we found that the phase separation-mediated IRS-1 puncta attached to endoplasmic reticulum (ER). VAPB, an ER-anchored protein that mediates tethers between ER and membranes of other organelles, was identified as a direct interacting partner of IRS-1. VAPB mainly binds active IRS-1 because IGF-1 enhanced the VAPB-IRS-1 association and replacing of the nine tyrosine residues of YXXM motifs disrupted the VAPB-IRS-1 association. We further delineated that the Y745 and Y746 residues in the FFAT-like motif of IRS-1 mediated the association with VAPB. Notably, VAPB targeted IRS-1 to the ER and subsequently maintained its stability. Consistently, ablation of VAPB in mice led to downregulation of IRS-1, suppression of insulin signaling, and glucose intolerance. The amyotrophic lateral sclerosis (ALS)-derived VAPB P56S mutant also impaired IRS-1 stability by interfering with the ER-tethering of IRS-1. Our findings thus revealed a previously unappreciated condensate-membrane contact (CMC), by which VAPB stabilizes the membraneless IRS-1 signalosome through targeting it to ER membrane.

CELLULAR SENESCENCE IMPLICATED IN SEPSIS-INDUCED MUSCLE WEAKNESS AND AMELIORATED WITH METFORMIN.

ABSTRACT: Background: Sepsis is a life-threatening medical emergency, frequently complicated with intensive care unit-acquired weakness syndrome (ICU-AW). ICU-AW patients display flaccid weakness of the limbs, especially in the proximal limb muscles. However, little is known regarding its pathogenesis. Here, we aimed to identify the potential signaling pathway involved in ICU-AW regulation and identify a potential therapeutic drug for intervention. Methods: Both in vivo and in vitro septic mice were used. For the in vivo septic mice, either cecum ligation and puncture or intraperitoneal injection of LPS was conducted in mice. The body weight and muscle mass were then measured and recorded. Muscle strength was evaluated by limb grip strength test. The expression of proteins extracted from cells and muscles was checked through Western blot analysis. Quantitative reverse transcription-polymerase chain reaction was carried out to test the transcriptional level of genes. Senescence-associated ß-galactosidase (SA-ß-gal) staining and Sirius red for collagen staining were conducted. Metformin, as an antiaging agent, was then tested for any attenuation of sepsis-related symptoms. For in vitro sepsis modeling, myoblasts were treated with LPS, analyzed for senescence-related protein expression, and subsequently retested upon metformin treatment. Results: We found that both the weight and strength of muscle were dramatically reduced in cecum ligation and puncture- or LPS-induced septic mice. RNA-seq analysis revealed that various cellular senescent genes were involved in sepsis. In line with this, expression of senescence-related genes, p53 and p21 were both upregulated. Both SA-ß-gal and Sirius red for collagen staining were enhanced in tibialis anterior muscles. Notably, inhibition of p53 expression by siRNA prominently reduced the number of SA-ß-gal-positive myoblasts upon LPS treatment. This indicated sepsis-induced cellular senescence to be dependent on p53. Consistent with the function of metformin in antiaging, metformin attenuated cellular senescence in both murine myoblasts and skeletal muscles during sepsis. Muscle strength of septic mice was improved upon metformin treatment. Metformin intervention is therefore proposed as a potential therapeutic strategy for ICU-AW. Conclusion: Taken together, we revealed a previously unappreciated linkage between cellular senescence and sepsis-induced muscle weakness and propose metformin as a potential therapeutic drug for the treatment of ICU-AW.

Phase separation of insulin receptor substrate 1 drives the formation of insulin/IGF-1 signalosomes.

As a critical node for insulin/IGF signaling, insulin receptor substrate 1 (IRS-1) is essential for metabolic regulation. A long and unstructured C-terminal region of IRS-1 recruits downstream effectors for promoting insulin/IGF signals. However, the underlying molecular basis for this remains elusive. Here, we found that the C-terminus of IRS-1 undergoes liquid-liquid phase separation (LLPS). Both electrostatic and hydrophobic interactions were seen to drive IRS-1 LLPS. Self-association of IRS-1, which was mainly mediated by the 301-600 region, drives IRS-1 LLPS to form insulin/IGF-1 signalosomes. Moreover, tyrosine residues of YXXM motifs, which recruit downstream effectors, also contributed to IRS-1 self-association and LLPS. Impairment of IRS-1 LLPS attenuated its positive effects on insulin/IGF-1 signaling. The metabolic disease-associated G972R mutation impaired the self-association and LLPS of IRS-1. Our findings delineate a mechanism in which LLPS of IRS-1-mediated signalosomes serves as an organizing center for insulin/IGF-1 signaling and implicate the role of aberrant IRS-1 LLPS in metabolic diseases.

AMPK-mediated phosphorylation enhances the auto-inhibition of TBC1D17 to promote Rab5-dependent glucose uptake.

Dysregulation of glucose homeostasis contributes to insulin resistance and type 2 diabetes. Whilst exercise stimulated activation of AMP-activated protein kinase (AMPK), an important energy sensor, has been highlighted for its potential to promote insulin-stimulated glucose uptake, the underlying mechanisms for this remain largely unknown. Here we found that AMPK positively regulates the activation of Rab5, a small GTPase which is involved in regulating Glut4 translocation, in both myoblasts and skeletal muscles. We further verified that TBC1D17, identified as a potential interacting partner of Rab5 in our recent study, is a novel GTPase activating protein (GAP) of Rab5. TBC1D17-Rab5 axis regulates transport of Glut1, Glut4, and transferrin receptor. TBC1D17 interacts with Rab5 or AMPK via its TBC domain or N-terminal 1-306 region (N-Ter), respectively. Moreover, AMPK phosphorylates the Ser 168 residue of TBC1D17 which matches the predicted AMPK consensus motif. N-Ter of TBC1D17 acts as an inhibitory region by directly interacting with the TBC domain. Ser168 phosphorylation promotes intra-molecular interaction and therefore enhances the auto-inhibition of TBC1D17. Our findings reveal that TBC1D17 acts as a molecular bridge that links AMPK and Rab5 and delineate a previously unappreciated mechanism by which the activation of TBC/RabGAP is regulated.

Rab5a activates IRS1 to coordinate IGF-AKT-mTOR signaling and myoblast differentiation during muscle regeneration.

Rab5 is a master regulator for endosome biogenesis and transport while its in vivo physiological function remains elusive. Here, we find that Rab5a is upregulated in several in vivo and in vitro myogenesis models. By generating myogenic Rab5a-deficient mice, we uncover the essential roles of Rab5a in regulating skeletal muscle regeneration. We further reveal that Rab5a promotes myoblast differentiation and directly interacts with insulin receptor substrate 1 (IRS1), an essential scaffold protein for propagating IGF signaling. Rab5a interacts with IRS1 in a GTP-dependent manner and this interaction is enhanced upon IGF-1 activation and myogenic differentiation. We subsequently identify that the arginine 207 and 222 of IRS1 and tyrosine 82, 89, and 90 of Rab5a are the critical amino acid residues for mediating the association. Mechanistically, Rab5a modulates IRS1 activation by coordinating the association between IRS1 and the IGF receptor (IGFR) and regulating the intracellular membrane targeting of IRS1. Both myogenesis-induced and IGF-evoked AKT-mTOR signaling are dependent on Rab5a. Myogenic deletion of Rab5a also reduces the activation of AKT-mTOR signaling during skeletal muscle regeneration. Taken together, our study uncovers the physiological function of Rab5a in regulating muscle regeneration and delineates the novel role of Rab5a as a critical switch controlling AKT-mTOR signaling by activating IRS1.

Hsp90ß interacts with MDM2 to suppress p53-dependent senescence during skeletal muscle regeneration.

Cellular senescence plays both beneficial and detrimental roles in embryonic development and tissue regeneration, while the underlying mechanism remains elusive. Recent studies disclosed the emerging roles of heat-shock proteins in regulating muscle regeneration and homeostasis. Here, we found that Hsp90ß, but not Hsp90α isoform, was significantly upregulated during muscle regeneration. RNA-seq analysis disclosed a transcriptional elevation of p21 in Hsp90ß-depleted myoblasts, which is due to the upregulation of p53. Moreover, knockdown of Hsp90ß in myoblasts resulted in p53-dependent cellular senescence. In contrast to the notion that Hsp90 interacts with and protects mutant p53 in cancer, Hsp90ß preferentially bound to wild-type p53 and modulated its degradation via a proteasome-dependent manner. Moreover, Hsp90ß interacted with MDM2, the chief E3 ligase of p53, to regulate the stability of p53. In line with these in vitro studies, the expression level of p53-p21 axis was negatively correlated with Hsp90ß in aged mice muscle. Consistently, administration of 17-AAG, a Hsp90 inhibitor under clinical trial, impaired muscle regeneration by enhancing injury-induced senescence in vivo. Taken together, our finding revealed a previously unappreciated role of Hsp90ß in regulating p53 stability to suppress senescence both in vitro and in vivo.

Hsp70 Interacts with Mitogen-Activated Protein Kinase (MAPK)-Activated Protein Kinase 2 To Regulate p38MAPK Stability and Myoblast Differentiation during Skeletal Muscle Regeneration.

The regenerative process of injured muscle is dependent on the fusion and differentiation of myoblasts derived from muscle stem cells. Hsp70 is important for maintaining skeletal muscle homeostasis and regeneration, but the precise cellular mechanism remains elusive. In this study, we found that Hsp70 was upregulated during myoblast differentiation. Depletion or inhibition of Hsp70/Hsc70 impaired myoblast differentiation. Importantly, overexpression of p38 mitogen-activated protein kinase α (p38MAPKα) but not AKT1 rescued the impairment of myogenic differentiation in Hsp70- or Hsc70-depleted myoblasts. Moreover, Hsp70 interacted with MK2, a substrate of p38MAPK, to regulate the stability of p38MAPK. Knockdown of Hsp70 also led to downregulation of both MK2 and p38MAPK in intact muscles and during cardiotoxin-induced muscle regeneration. Hsp70 bound MK2 to regulate MK2-p38MAPK interaction in myoblasts. We subsequently identified the essential regions required for Hsp70-MK2 interaction. Functional analyses showed that MK2 is essential for both myoblast differentiation and skeletal muscle regeneration. Taken together, our findings reveal a novel role of Hsp70 in regulating myoblast differentiation by interacting with MK2 to stabilize p38MAPK.

Chimeric Antigen Receptor-T Cells with 4-1BB Co-Stimulatory Domain Present a Superior Treatment Outcome than Those with CD28 Domain Based on Bioinformatics.

BACKGROUND: The second-generation CD19-chimeric antigen receptor (CAR)-T co-stimulatory domain that is commonly used in clinical practice is CD28 or 4-1BB. Previous studies have shown that the persistence of CAR-T in the 4-1BB co-stimulatory domain appears to be longer. METHODS: The expression profile data of GSE65856 were obtained from GEO database. After data preprocessing, the differentially expressed genes (DEGs) between the mock CAR versus CD19-28z CAR T cells and mock CAR versus CD19-BBz CAR T cells were identified using the limma package. Subsequently, functional enrichment analysis of DEGs was performed using the DAVID tool. Then, the protein-protein international (PPI) network of these DEGs was visualized by Cytoscape, and the miRNA-target gene-disease regulatory networks were predicted using Webgestal. RESULTS: A total of 18 common DEGs, 6 CD19-28z specific DEGs and 206 CD19-BBz specific DEGs were identified. Among CD19-28z specific DEGs, down-regulated PAX5 might be an important node in the PPI network and could be targeted by miR-496. In CD19-BBz group, JUN was a hub node in the PPI network and involved in the regulations of miR520D - early growth response gene 3 (EGR3)-JUN and mi-R489-AT-rich interaction domain 5A (ARID5A)-JUN networks. CONCLUSION: The 4-1BB co-stimulatory domain might play in important role in the treatment of CAR-T via miR-520D-EGR3-JUN and miR489-ARID5A-JUN regulation network, while CD28 had a negative effect on CAR-T treatment.

Activation of AKT-mTOR Signaling Directs Tenogenesis of Mesenchymal Stem Cells.

Tendon repair is a clinical challenge because of the limited understanding on tenogenesis. The synthesis of type I collagen (Collagen I) and other extracellular matrix are essential for tendon differentiation and homeostasis. Current studies on tenogenesis focused mostly on the tenogenic transcriptional factors while the signaling controlling tenogenesis on translational level remains largely unknown. Here, we showed that mechanistic target of rapamycin (mTOR) signaling was activated by protenogenic growth factor, transforming growth factors beta1, and insulin-like growth factor-I. The expression of mTOR was upregulated during tenogenesis of mesenchymal stem cells (MSCs). Moreover, mTOR was downregulated in human tendinopathy tissues and was inactivated upon statin treatment. Both inhibition and depletion of AKT or mTOR significantly reduced type I collagen production and impaired tenogenesis of MSCs. Tendon specific-ablation of mTOR resulted in tendon defect and reduction of Collagen I. However, there is no evident downregulation of tendon associated collagens at the transcription level. Our study demonstrated that AKT-mTOR axis is a key mediator of tendon differentiation and provided a novel therapeutic target for tendinopathy and tendon injuries. Stem Cells 2018;36:527-539.

Influence of the large-small split effect on strategy choice in complex subtraction.

Two main theories have been used to explain the arithmetic split effect: decision-making process theory and strategy choice theory. Using the inequality paradigm, previous studies have confirmed that individuals tend to adopt a plausibility-checking strategy and a whole-calculation strategy to solve large and small split problems in complex addition arithmetic, respectively. This supports strategy choice theory, but it is unknown whether this theory also explains performance in solving different split problems in complex subtraction arithmetic. This study used small, intermediate and large split sizes, with each split condition being further divided into problems requiring and not requiring borrowing. The reaction times (RTs) for large and intermediate splits were significantly shorter than those for small splits, while accuracy was significantly higher for large and middle splits than for small splits, reflecting no speed-accuracy trade-off. Further, RTs and accuracy differed significantly between the borrow and no-borrow conditions only for small splits. This study indicates that strategy choice theory is suitable to explain the split effect in complex subtraction arithmetic. That is, individuals tend to choose the plausibility-checking strategy or the whole-calculation strategy according to the split size.

Knockdown of REGγ inhibits the proliferation and migration and promotes the apoptosis of multiple myeloma cells by downregulating NF-κB signal pathway.

OBJECTIVES: This study aimed to evaluate the effects of REGγ knockdown on the proliferation, apoptosis and migration of multiple myeloma (MM) cells, and reveal the potential regulatory mechanisms. METHODS: The expression of REGγ on myeloma cells of 28 MM patients was detected by Western blot. shRNA-REGγ-1 and shRNA-REGγ-2 were constructed to downregulate REGγ in RPMI-8226 cells. The proliferation, apoptosis and migration of transfected cells were analyzed by Cell Counting Kit 8 (CCK8), flow cytometry and transwell chamber, respectively. The expression of phosphorylated p65 (p-p65), p65, NF-kappa-B inhibitor ε (IkBε), matrix metalloproteinase 2 (MMP2), B-cell lymphoma xL (Bcl-xL) and X-linked inhibitor of apoptosis protein (XIAP) in transfected cells was detected by Western blot. Using cycloheximide (CHX), the half-life period of IkBε was detected by Western blot. RESULTS: The expression of REGγ was positive in myeloma cells. The proliferation and migration of RPMI-8226 cells were significantly inhibited by shRNA-REGγ-1/shRNA-REGγ-2, while the apoptosis rates were significantly increased (p < 0.05). The expression of p-p65 and IkBε was significantly reduced in RPMI-8226 cells transfected with shRNA-REGγ-1/shRNA-REGγ-2. The degradation of IkBε was significantly lower in RPMI-8226 cells transfected with shRNA-REGγ-1 than the control (longer half-life period). Besides, the expression of MMP2, Bcl-xL and XIAP in RPMI-8226 cells was significantly inhibited by shRNA-REGγ-1/shRNA-REGγ-2. DISCUSSION: Knockdown of REGγ may inhibit the proliferation and migration, and promote the apoptosis of RPMI-8226 cells possibly by downregulating NF-κB signal pathway.

Integration of the metabolic/redox state, histone gene switching, DNA replication and S-phase progression by moonlighting metabolic enzymes.

The concept of one-protein-multiple-function, i.e. moonlighting proteins, is an ever-expanding paradigm. We obtained compelling evidence that an array of 'cytoplasmic' metabolic enzymes can enter the nuclei to carry out moonlighting transcription functions; this phenomenon is conserved from Drosophila to humans. Of particular interest are the classical glycolytic enzymes GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and LDH (lactate dehydrogenase), which utilize NAD(H) as coenzymes and not only moonlight (in their nuclear forms) to regulate the transcription of S-phase-specific histone genes, but also act as metabolic/redox sensors that link histone gene switching to DNA replication and S-phase progression.

[Allogeneic hematopoietic stem cell transplantation for the treatment of mucopolysaccharidosis type 1: a case report].

Mucopolysaccharidosis type I (MPS-I) is an inborn error of metabolism with progressive multisystem involvement. Hurler syndrome is the most severe form of MPS-I that causes progressive deterioration of the central nervous system with ensuing death. This study reported the therapeutic effect of allogeneic hematopoietic stem cell transplantation (allo-HSCT) on Hurler syndrome in one case. The patient was a 25-month-old boy. He underwent allo-HSCT. The donor was his elder sister whose HLA-B locus was not matching. The reduced-intensity of BuCy conditioning regimen in allo-HSCT for this patient was as follows: busulfan 3.7 mg/kg daily at 9 to 6 days before transplantation, cyclophosphamide 42.8 mg/kg daily at 5 to 2 days before transplantation, and rabbit antithymocyte globulin 3.5 mg/kg daily at 1, 3, 5, and 7 days before transplantation. Human granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (CD34+ cells 12.8 x10(6)/kg) were infused and cyclosporine (CSA), short-course methotrexate, daclizumab and mycophenolate mofetil (MMF) were administered to prevent graft-versus-host disease (GVHD). Complete donor-type engraftment was confirmed by Short Tandem Repeat-Polymerase Chain Reaction (STR-PCR) on day 14 after transplantation. Neutrophil and platelet engraftment occurred on days 11 and 19 after transplantation respectively. Only grade I regimen-related toxicity of live and gastrointestinal tract occurred. GVHD and graft failure were not observed. After transplantation, the clinical symptoms and the neurocognitive function were greatly improved in this patient. It was concluded that allo-HSCT was effective for the treatment of MPS-I. The reduced-intensity conditioning regimen was helpful to decrease the regimen-related toxicity. Sufficient immunosuppressive therapy and adequate hematopoietic stem cells infusion may be beneficial to the donor cell engraftment and reducing the incidence of graft failure and GVHD.