Citations

Abstract Heterotopic ossification (HO), often arising in response to traumatic challenges, results from the aberrant osteochondral differentiation of mesenchymal stem cells (MSCs). Nevertheless, the impact of trauma‐induced inflammatory exposure on MSC fate determination remains ambiguous. In this study, the cellular diversity within inflammatory lesions is elucidated, comprising MSCs and several innate and adaptive immune cells. It is observed that quiescent MSCs transition into cycling MSCs, subsequently giving rise to chondrogenic (cMSC) and/or osteogenic (oMSC) lineages within the inflammatory microenvironment following muscle or tendon injuries, as revealed through single‐cell RNA sequencing (scRNA‐seq), spatial transcriptome and lineage tracing analysis. Moreover, these investigations demonstrate that neutrophils and natural killer (NK) cells enhance transition of quiescent MSCs into cycling MSCs, which is also controlled by M1 macrophages, a subpopulation of macrophages can also stimulate cMSC and oMSC production from cycling MSCs. Additionally, M2 macrophages, CD4 + and CD8 + T lymphocytes are found to promote chondrogenesis. Further analysis demonstrates that immune cells promotes the activation of signaling transducers and activators of transcription (STAT) pathway and phosphoinositide 3 (PI3K)/protein kinase B (AKT) pathway in MSC proliferation and osteochondral progenitors’ production, respectively. These findings highlight the dynamics of MSC fate within the inflammatory lesion and unveil the molecular landscape of osteoimmunological interactions, which holds promise for advancing HO treatment.

Aggregated α-synuclein (α-SYN) proteins, encoded by the SNCA gene, are hallmarks of Lewy body disease (LBD), affecting multiple brain regions. However, the specific mechanisms underlying α-SYN pathology in cortical neurons, crucial for LBD-associated dementia, remain unclear. Here, we recapitulated α-SYN pathologies in human induced pluripotent stem cells (iPSCs)–derived cortical organoids generated from patients with LBD with SNCA gene triplication. Single-cell RNA sequencing, combined with functional and molecular validation, identified synaptic and mitochondrial dysfunction in excitatory neurons exhibiting high expression of the SNCA gene, aligning with observations in the cortex of autopsy-confirmed LBD human brains. Furthermore, we screened 1280 Food and Drug Administration–approved drugs and identified four candidates (entacapone, tolcapone, phenazopyridine hydrochloride, and zalcitabine) that inhibited α-SYN seeding activity in real-time quaking-induced conversion assays with human brains, reduced α-SYN aggregation, and alleviated mitochondrial dysfunction in SNCA triplication organoids and excitatory neurons. Our findings establish human cortical LBD models and suggest potential therapeutic drugs targeting α-SYN aggregation for LBD.

Abstract B cell activation is accompanied by dynamic metabolic reprogramming, supported by a multitude of nutrients that include glucose, amino acids, and fatty acids. Although several studies have indicated that fatty acid mitochondrial oxidation is critical for immune cell functions, contradictory findings have been reported. Carnitine palmitoyltransferase II (CPT2) is a critical enzyme for long-chain fatty acid oxidation in mitochondria. In this study, we test the requirement of CPT2 for humoral immunity using a mouse model with a lymphocyte-specific deletion of CPT2. Stable [13C] isotope tracing reveals highly reduced fatty acid–derived citrate production in CPT2-deficient B cells. Yet, CPT2 deficiency has no significant impact on B cell development, B cell activation, germinal center formation, and Ab production upon either thymus-dependent or -independent Ag challenges. Together, our findings indicate that CPT2-mediated fatty acid oxidation is dispensable for humoral immunity, highlighting the metabolic flexibility of lymphocytes.

Abstract Clinical and preclinical research has demonstrated that iPSC-derived NK (iNK) cells have a high therapeutic potential, yet poor understanding of the detailed process of their differentiation in vitro and their counterpart cell development in vivo has hindered therapeutic iNK cell production and engineering. Here we dissect the crucial differentiation of both fetal liver NK cells and iNK cells to enable the rational design of advanced iNK production protocols. We use a comparative analysis of single-cell RNA-seq (scRNA-seq) to pinpoint key factors lacking in the induced setting which we hypothesized would hinder iNK differentiation and/ or functionality. By analyzing key transcription factor regulatory networks, we discovered the importance of TBX21, EOMES, and STAT5A in the differentiation timeline. This analysis provides a blueprint for further engineering new iPSC lines to obtain iNK cells with enhanced functions. We validated this approach by creating a new line of STAT5A-iPSCs which can be differentiated to STAT5A-expressing macrophages with both NK cell and macrophage features such as perforin production, phagocytosis, and anti-tumor functions.

Purpose To evaluate the effectiveness of microfragmented adipose tissue (MFAT) for pain relief and improved joint functionality in osteoarthritis (OA) of the knee in a randomized controlled clinical trial with 1‐year follow‐up. Methods Seventy‐five patients were stratified by baseline pain level and randomized to 1 of 3 treatment groups: MFAT, corticosteroid (CS), or saline control (C) injection. Patients 18 years of age or older, diagnosed with symptomatic OA of the knee, with radiographic evidence of OA of the knee and a visual analog pain scale score of 3 of 10 or greater were included. Patients were excluded if they had any previous intra‐articular knee injection, current knee ligamentous instability, or an allergy to lidocaine/corticosteroid. The visual analog pain scale, Western Ontario and McMaster Universities Osteoarthritis Index, and the Knee Injury and Osteoarthritis Outcome score (KOOS) were recorded preprocedure and at 2 weeks, 6 weeks, 3 and 6 months, and 1‐year follow‐up. Results MFAT demonstrated consistent and statistically significant improvements across all primary outcome measures for joint pain and functionality compared with C. For MFAT, there was a significant improvement over baseline at each follow‐up, with median (95% confidence interval) KOOS Pain score changes of 18.1 (11.1‐26.4) at week 2 to 27.8 (19.4‐37.5) at 1 year. For CS, the median KOOS pain score reached a maximum of 22.2 (15.3‐30.6) at week 2, only to level off to 13.9 (–2.8 to 29.2), a level not statistically different from baseline, at 1 year. The median changes for C hovered around 6 to 11 points, with statistically significant improvements over baseline indicating a placebo effect. Similar trends were seen for the Western Ontario and McMaster Universities Osteoarthritis Index Pain score and VAS Pain score. Conclusions In this study, MFAT demonstrated a clinically significant improvement in primary outcome scores compared with the C group, whereas the CS group only showed statistically significant improvement compared with the C group at 2 and 6 weeks. This finding indicates that MFAT may be a viable alternative treatment for patients with OA of the knee who fall into the orthopaedic treatment gap. Level of Evidence Level II, partially blinded, randomized controlled clinical trial.

ABSTRACTIntroductionLow body weight in patients with COPD is associated with a poor prognosis and more comorbidities. However, the impact of increased body weight in patients with COPD remains controversial. The aim of this study was to explore the clinical features of overweight patients with AECOPD.MethodsIn this multicenter cross‐sectional study, a total of 647 AECOPD patients were recruited. Finally, 269 normal weight and 162 overweight patients were included. Baseline characteristics and clinical and laboratory data were collected. The least absolute shrinkage and selection operator (LASSO) regression was performed to determine potential features, which were substituted into binary logistic regression to reveal overweight‐associated clinical features. The nomogram and its associated curves were established to visualize and verify the logistic regression model.ResultsSix potential overweight‐associated variables were selected by LASSO regression. Subsequently, a binary logistic regression model identified that the rates of type 2 diabetes (T2DM) and hypertension and levels of lymphocytes (LYM)%, and alanine aminotransferase (ALT) were independent variables of overweight in AECOPD patients. The C‐index and AUC of the ROC curve of the nomogram were 0.671 and 0.666, respectively. The DCA curve revealed that the nomogram had more clinical benefits if the threshold was at a range of 0.22~0.78.ConclusionsCollectively, we revealed that T2DM and hypertension were more common, and LYM% and ALT were higher in AECOPD patients with overweight than those with normal weight. The result suggests that AECOPD patients with overweight are at risk for additional comorbidities, potentially leading to worse outcomes.

BACKGROUND: Apelin is an endogenous prepropeptide that regulates cardiac homeostasis and various physiological processes. Intravenous injection has been shown to improve cardiac contractility in patients with heart failure. However, its short half-life prevents studying its impact on left ventricular remodeling in the long term. Here, we aim to study whether microparticle-mediated slow release of apelin improves heart function and left ventricular remodeling in mice with myocardial infarction (MI). METHODS: A cardiac patch was fabricated by embedding apelin-containing microparticles in a fibrin gel scaffold. MI was induced via permanent ligation of the left anterior descending coronary artery in adult C57BL/6J mice followed by epicardial patch placement immediately after (acute MI) or 28 days (chronic MI) post-MI. Four groups were included in this study, namely sham, MI, MI plus empty microparticle-embedded patch treatment, and MI plus apelin-containing microparticle-embedded patch treatment. Cardiac function was assessed by transthoracic echocardiography. Cardiomyocyte morphology, apoptosis, and cardiac fibrosis were evaluated by histology. Cardioprotective pathways were determined by RNA sequencing, quantitative polymerase chain reaction, and Western blot. RESULTS: The level of endogenous apelin was largely reduced in the first 7 days after MI induction and it was normalized by day 28. Apelin-13 encapsulated in poly(lactic-co-glycolic acid) microparticles displayed a sustained release pattern for up to 28 days. Treatment with apelin-containing microparticle-embedded patch inhibited cardiac hypertrophy and reduced scar size in both acute and chronic MI models, which is associated with improved cardiac function. Data from cellular and molecular analyses showed that apelin inhibits the activation and proliferation of cardiac fibroblasts by preventing transforming growth factor-β–mediated activation of Smad2/3 (supporessor of mothers against decapentaplegic 2/3) and downstream profibrotic gene expression. CONCLUSIONS: Poly(lactic-co-glycolic acid) microparticles prolonged the apelin release time in the mouse hearts. Epicardial delivery of the apelin-containing microparticle-embedded patch protects mice from both acute and chronic MI-induced cardiac dysfunction, inhibits cardiac fibrosis, and improves left ventricular remodeling.

Aging is a prominent risk factor for numerous chronic diseases. Understanding the shared mechanisms of aging can aid in pinpointing therapeutic targets for age-related disorders. Chronic inflammation has emerged as a pivotal mediator of aging and a determinant in various age-related chronic conditions. Recent findings indicate that C-C motif chemokine ligand 2 and receptor 2 (CCL2-CCR2) signaling, an important physiological modulator in innate immune response and inflammatory defense, plays a crucial role in aging-related disorders and is increasingly recognized as a promising therapeutic target, highlighting its significance. This review summarizes recent advances in the investigation of CCL2-CCR2 signaling in cardiovascular and neural aging, as well as in various aging-related disorders. It also explores the underlying mechanisms and therapeutic potentials in these contexts. These insights aim to deepen our understanding of aging pathophysiology and the development of aging-related diseases.

Abstract Although the functions of tyrosine phosphatases in T‐cell biology have been extensively studied, our knowledge on the contribution of serine/threonine phosphatases in T cells remains poor. Protein phosphatase 2A (PP2A) is one of the most abundantly expressed serine/threonine phosphatases. It is important in thymocyte development and CD4 + T‐cell differentiation. Utilizing a genetic model in which its catalytic subunit alpha isoform (PP2A Cα) is deleted in T cells, we investigated its contribution to CD8 + T‐cell homeostasis and effector functions. Our results demonstrate that T‐cell intrinsic PP2A Cα is critically required for CD8 + T‐cell homeostasis in secondary lymphoid organs and intestinal mucosal site. Importantly, PP2A Cα–deficient CD8 + T cells exhibit reduced proliferation and survival. CD8 + T‐cell antibacterial response is strictly dependent on PP2A Cα. Expression of Bcl2 transgene rescues CD8 + T‐cell homeostasis in spleens, but not in intestinal mucosal site, nor does it restore defective antibacterial responses. Finally, proteomics and phosphoproteomics analyses reveal potential targets dependent on PP2A Cα, including mTORC1 and AKT. Thus, PP2A Cα is a key modulator of CD8 + T‐cell homeostasis and effector functions.