A simplified system for generating recombinant adenoviruses

An engineered TNFR1-selective human lymphotoxin-alpha mutant delivered by an oncolytic adenovirus for tumor immunotherapy

Lymphotoxin α (LTα) is a soluble factor produced by activated lymphocytes which is cytotoxic to tumor cells. Although a promising candidate in cancer therapy, the application of recombinant LTα has been limited by its instability and toxicity by systemic administration. Secreted LTα interacts with several distinct receptors for its biological activities. Here, we report a TNFR1-selective human LTα mutant (LTα Q107E) with potent antitumor activity. Recombinant LTα Q107E with N-terminal 23 and 27 aa deletion (named LTα Q1 and Q2, respectively) showed selectivity to TNFR1 in both binding and NF-κB pathway activation assays. To test the therapeutic potential, we constructed an oncolytic adenovirus (oAd) harboring LTα Q107E Q2 mutant (named oAdQ2) and assessed the antitumor effect in mouse xenograft models. Intratumoral delivery of oAdQ2 inhibited tumor growth. In addition, oAdQ2 treatment enhanced T cell and IFNγ-positive CD8 T lymphocyte infiltration in a human PBMC reconstituted-SCID mouse xenograft model. This study provides evidence that reengineering of bioactive cytokines with tissue or cell specific properties may potentiate their therapeutic potential of cytokines with multiple receptors.

Cross-protective efficacy and safety of an adenovirus-based universal influenza vaccine expressing nucleoprotein, hemagglutinin, and the ectodomain of matrix protein 2

It is necessary to develop universal vaccines that act broadly and continuously to combat regular seasonal epidemics of influenza and rare pandemics. The aim of this study was to find the optimal dose regimen for the efficacy and safety of a mixture of previously developed recombinant adenovirus-based vaccines that expressed influenza nucleoprotein, hemagglutinin, and ectodomain of matrix protein 2 (rAd/NP and rAd/HA-M2e). The vaccine efficacy and safety were measured in the immunized mice with the mixture of rAd/NP and rAd/HA-M2e intranasally or intramuscularly. The minimum dose that would be efficacious in a single intranasal administration of the vaccine mixture and cross-protective efficacy against various influenza strains were examined. In addition, the immune responses that may affect the cross-protective efficacy were measured. We found that intranasal administration is an optimal route for 107 pfu of vaccine mixture, which is effective against pre-existing immunity against adenovirus. In a study to find the minimum dose with vaccine efficacy, the 106 pfu of vaccine mixture showed higher antibody titers to the nucleoprotein than did the same dose of rAd/NP alone in the serum of immunized mice. The 106 pfu of vaccine mixture overcame the morbidity and mortality of mice against the lethal dose of pH1N1, H3N2, and H5N1 influenza infections. No noticeable side effects were observed in single and repeated toxicity studies. We found that the mucosal administration of adenovirus-based universal influenza vaccine has both efficacy and safety, and can provide cross-protection against various influenza infections even at doses lower than those previously known to be effective.

Evaluation of two inoculation routes of an adenovirus-mediated viral protein inhibitor in a Crimean-Congo hemorrhagic fever mouse model

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne nairovirus with a wide geographic spread that can cause severe and lethal disease. No specific medical countermeasures are approved to combat this illness. The CCHFV L protein contains an ovarian tumor (OTU) domain with a cysteine protease thought to modulate cellular immune responses by removing ubiquitin and ISG15 post-translational modifications from host and viral proteins. Viral deubiquitinases like CCHFV OTU are attractive drug targets, as blocking their activity may enhance cellular immune responses to infection, and potentially inhibit viral replication itself. We previously demonstrated that the engineered ubiquitin variant CC4 is a potent inhibitor of CCHFV replication in vitro. A major challenge of the therapeutic use of small protein inhibitors such as CC4 is their requirement for intracellular delivery, e.g., by viral vectors. In this study, we examined the feasibility of in vivo CC4 delivery by a replication-deficient recombinant adenovirus (Ad-CC4) in a lethal CCHFV mouse model. Since the liver is a primary target of CCHFV infection, we aimed to optimize delivery to this organ by comparing intravenous (tail vein) and intraperitoneal injection of Ad-CC4. While tail vein injection is a traditional route for adenovirus delivery, in our hands intraperitoneal injection resulted in higher and more widespread levels of adenovirus genome in tissues, including, as intended, the liver. However, despite promising in vitro results, neither route of in vivo CC4 treatment resulted in protection from a lethal CCHFV infection.

Identification and characterisation of functional Kir6.1-containing ATP-sensitive potassium channels in the cardiac ventricular sarcolemmal membrane

BACKGROUND AND PURPOSE

The canonical Kir6.2/SUR2A ventricular KATP channel is highly ATP-sensitive and remains closed under normal physiological conditions. These channels activate only when prolonged metabolic compromise causes significant ATP depletion and then shortens the action potential to reduce contractile activity. Pharmacological activation of KATP channels is cardioprotective, but physiologically, it is difficult to understand how these channels protect the heart if they only open under extreme metabolic stress. The presence of a second KATP channel population could help explain this. Here, we characterise the biophysical and pharmacological behaviours of a constitutively active Kir6.1-containing KATP channel in ventricular cardiomyocytes.

EXPERIMENTAL APPROACH

Patch-clamp recordings from rat ventricular myocytes in combination with well-defined pharmacological modulators was used to characterise these newly identified K+ channels. Action potential recording, calcium (Fluo-4) fluorescence measurements and video edge detection of contractile function were used to assess functional consequences of channel modulation.

KEY RESULTS

Our data show a ventricular K+ conductance whose biophysical characteristics and response to pharmacological modulation were consistent with Kir6.1-containing channels. These Kir6.1-containing channels lack the ATP-sensitivity of the canonical channels and are constitutively active.

CONCLUSION AND IMPLICATIONS

We conclude there are two functionally distinct populations of ventricular KATP channels: constitutively active Kir6.1-containing channels that play an important role in fine-tuning the action potential and Kir6.2/SUR2A channels that activate with prolonged ischaemia to impart late-stage protection against catastrophic ATP depletion. Further research is required to determine whether Kir6.1 is an overlooked target in Comprehensive in vitro Proarrhythmia Assay (CiPA) cardiac safety screens.

ISG15 blocks cardiac glycolysis and ensures sufficient mitochondrial energy production during Coxsackievirus B3 infection

AIMS

Virus infection triggers inflammation and, may impose nutrient shortage to the heart. Supported by type I interferon (IFN) signalling, cardiomyocytes counteract infection by various effector processes, with the IFN-stimulated gene of 15 kDa (ISG15) system being intensively regulated and protein modification with ISG15 protecting mice Coxsackievirus B3 (CVB3) infection. The underlying molecular aspects how the ISG15 system affects the functional properties of respective protein substrates in the heart are unknown.

METHODS AND RESULTS

Based on the protective properties due to protein ISGylation, we set out a study investigating CVB3-infected mice in depth and found cardiac atrophy with lower cardiac output in ISG15-/- mice. By mass spectrometry, we identified the protein targets of the ISG15 conjugation machinery in heart tissue and explored how ISGylation affects their function. The cardiac ISGylome showed a strong enrichment of ISGylation substrates within glycolytic metabolic processes. Two control enzymes of the glycolytic pathway, hexokinase 2 (HK2) and phosphofructokinase muscle form (PFK1), were identified as bona fide ISGylation targets during infection. In an integrative approach complemented with enzymatic functional testing and structural modelling, we demonstrate that protein ISGylation obstructs the activity of HK2 and PFK1. Seahorse-based investigation of glycolysis in cardiomyocytes revealed that, by conjugating proteins, the ISG15 system prevents the infection-/IFN-induced up-regulation of glycolysis. We complemented our analysis with proteomics-based advanced computational modelling of cardiac energy metabolism. Our calculations revealed an ISG15-dependent preservation of the metabolic capacity in cardiac tissue during CVB3 infection. Functional profiling of mitochondrial respiration in cardiomyocytes and mouse heart tissue by Seahorse technology showed an enhanced oxidative activity in cells with a competent ISG15 system.

CONCLUSION

Our study demonstrates that ISG15 controls critical nodes in cardiac metabolism. ISG15 reduces the glucose demand, supports higher ATP production capacity in the heart, despite nutrient shortage in infection, and counteracts cardiac atrophy and dysfunction.

Leptin attenuates the osteogenic induction potential of BMP9 by increasing β-catenin malonylation modification via Sirt5 down-regulation

BMP9 has demonstrated significant osteogenic potential. In this study, we investigated the effect of Leptin on BMP9-induced osteogenic differentiation. Firstly, we found Leptin was decreased during BMP9-induced osteogenic differentiation and serum Leptin concentrations were increased in the ovariectomized (OVX) rats. Both in vitro and in vivo, exogenous expression of Leptin inhibited the process of osteogenic differentiation, whereas silencing Leptin enhanced. Exogenous Leptin could increase the malonylation of β-catenin. However, BMP9 could increase the level of Sirt5 and subsequently decrease the malonylation of β-catenin; the BMP9-induced osteogenic differentiation was inhibited by silencing Sirt5. These data suggested that Leptin can inhibit the BMP9-induced osteogenic differentiation, which may be mediated through reducing the activity of Wnt/β-catenin signalling via down-regulating Sirt5 to increase the malonylation level of β-catenin partly.

BMP9 induces osteogenic differentiation through up-regulating LGR4 via the mTORC1/Stat3 pathway in mesenchymal stem cells

Bone defects and non-union are prevalent in clinical orthopedy, and the outcomes of current treatments are often suboptimal. Bone tissue engineering offers a promising approach to treating these conditions effectively. Bone morphogenetic protein 9 (BMP9) can commit mesenchymal stem cells to osteogenic lineage, and a knowledge of the underlying mechanisms may help advance the field of bone tissue engineering. Leucine-rich repeats containing G protein-coupled receptor 4 (LGR4), a member of G protein-coupled receptors, is essential for modulating bone development. This study is aimed at investigating the impact of LGR4 on BMP9-induced osteogenesis in mesenchymal stem cells as well as the underlying mechanisms. Bone marrow stromal cells from BMP9-knockout mice exhibited diminished LGR4 expression, and exogenous LGR4 clearly restored the impaired osteogenic potency of the bone marrow stromal cells. Furthermore, LGR4 expression was increased by BMP9 in C3H10T1/2 cells. LGR4 augmented the benefits of BMP9-induced osteogenic markers and bone formation, whereas LGR4 inhibition restricted these effects. Meanwhile, the BMP9-induced lipogenic markers were increased by LGR4 inhibition. The protein levels of Raptor and p-Stat3 were elevated by BMP9. Raptor knockdown or p-Stat3 suppression attenuated the osteoblastic markers and LGR4 expression brought on by BMP9. LGR4 significantly reversed the blocking effect of Raptor knockdown or p-Stat3 suppression on the BMP9-induced osteoblastic markers. Raptor interacts with p-Stat3, and p-Stat3 activates the LGR4 promoter activity. In conclusion, LGR4 boosts BMP9 osteoblastic potency in mesenchymal stem cells, and BMP9 may up-regulate LGR4 via the mTORC1/Stat3 signal activation.

Sprouty genes regulate activated fibroblasts in mammary epithelial development and breast cancer

Stromal fibroblasts are a major stem cell niche component essential for organ formation and cancer development. Fibroblast heterogeneity, as revealed by recent advances in single-cell techniques, has raised important questions about the origin, differentiation, and function of fibroblast subtypes. In this study, we show in mammary stromal fibroblasts that loss of the receptor tyrosine kinase (RTK) negative feedback regulators encoded by Spry1, Spry2, and Spry4 causes upregulation of signaling in multiple RTK pathways and increased extracellular matrix remodeling, resulting in accelerated epithelial branching. Single-cell transcriptomic analysis demonstrated that increased production of FGF10 due to Sprouty (Spry) loss results from expansion of a functionally distinct subgroup of fibroblasts with the most potent branching-promoting ability. Compared to their three independent lineage precursors, fibroblasts in this subgroup are "activated," as they are located immediately adjacent to the epithelium that is actively undergoing branching and invasion. Spry genes are downregulated, and activated fibroblasts are expanded, in all three of the major human breast cancer subtypes. Together, our data highlight the regulation of a functional subtype of mammary fibroblasts by Spry genes and their essential role in epithelial morphogenesis and cancer development.

ATF6 protects against protein misfolding during cardiac hypertrophy

Cardiomyocytes activate the unfolded protein response (UPR) transcription factor ATF6 during pressure overload-induced hypertrophic growth. The UPR is thought to increase ER protein folding capacity and maintain proteostasis. ATF6 deficiency during pressure overload leads to heart failure, suggesting that ATF6 protects against myocardial dysfunction by preventing protein misfolding. However, conclusive evidence that ATF6 prevents toxic protein misfolding during cardiac hypertrophy is still pending. Here, we found that activation of the UPR, including ATF6, is a common response to pathological cardiac hypertrophy in mice. ATF6 KO mice failed to induce sufficient levels of UPR target genes in response to chronic isoproterenol infusion or transverse aortic constriction (TAC), resulting in impaired cardiac growth. To investigate the effects of ATF6 on protein folding, the accumulation of poly-ubiquitinated proteins as well as soluble amyloid oligomers were directly quantified in hypertrophied hearts of WT and ATF6 KO mice. Whereas only low levels of protein misfolding was observed in WT hearts after TAC, ATF6 KO mice accumulated increased quantities of misfolded protein, which was associated with impaired myocardial function. Collectively, the data suggest that ATF6 plays a critical adaptive role during cardiac hypertrophy by protecting against protein misfolding.

Adipose-derived mesenchymal stem cells (MSCs) are a superior cell source for bone tissue engineering

Effective bone regeneration through tissue engineering requires a combination of osteogenic progenitors, osteoinductive biofactors and biocompatible scaffold materials. Mesenchymal stem cells (MSCs) represent the most promising seed cells for bone tissue engineering. As multipotent stem cells that can self-renew and differentiate into multiple lineages including bone and fat, MSCs can be isolated from numerous tissues and exhibit varied differentiation potential. To identify an optimal progenitor cell source for bone tissue engineering, we analyzed the proliferative activity and osteogenic potential of four commonly-used mouse MSC sources, including immortalized mouse embryonic fibroblasts (iMEF), immortalized mouse bone marrow stromal stem cells (imBMSC), immortalized mouse calvarial mesenchymal progenitors (iCAL), and immortalized mouse adipose-derived mesenchymal stem cells (iMAD). We found that iMAD exhibited highest osteogenic and adipogenic capabilities upon BMP9 stimulation in vitro, whereas iMAD and iCAL exhibited highest osteogenic capability in BMP9-induced ectopic osteogenesis and critical-sized calvarial defect repair. Transcriptomic analysis revealed that, while each MSC line regulated a distinct set of target genes upon BMP9 stimulation, all MSC lines underwent osteogenic differentiation by regulating osteogenesis-related signaling including Wnt, TGF-β, PI3K/AKT, MAPK, Hippo and JAK-STAT pathways. Collectively, our results demonstrate that adipose-derived MSCs represent optimal progenitor sources for cell-based bone tissue engineering.

Mucosal tumor vaccination delivering endogenous tumor antigens protects against pulmonary breast cancer metastases

BACKGROUND

Generally, early-stage breast cancer has a good prognosis. However, if it spreads systemically, especially with pulmonary involvement, prospects worsen dramatically. Importantly, tumor-infiltrating T cells contribute to tumor control, particularly intratumoral T cells with a tissue-resident memory phenotype are associated with an improved clinical outcome.

METHODS

Here, we use an adenoviral vector vaccine encoding endogenous tumor-associated antigens adjuvanted with interleukin-1β to induce tumor-specific tissue-resident memory T cells (TRM) in the lung for the prevention and treatment of pulmonary metastases in the murine 4T1 breast cancer model.

RESULTS

The mucosal delivery of the vaccine was highly efficient in establishing tumor-specific TRM in the lung. Concomitantly, a single mucosal vaccination reduced the growth of pulmonary metastases and improved the survival in a prophylactic treatment. Vaccine-induced TRM contributed to these protective effects. In a therapeutic setting, the vaccination induced a pronounced T cell infiltration into metastases but resulted in only a minor restriction of the disease progression. However, in combination with stereotactic radiotherapy, the vaccine increased the survival time and rate of tumor-bearing mice.

CONCLUSION

In summary, our study demonstrates that mucosal vaccination is a promising strategy to harness the power of antitumor TRM and its potential combination with state-of-the-art treatments.

Advances of Recombinant Adenoviral Vectors in Preclinical and Clinical Applications

Adenoviruses (Ad) have the potential to induce severe infections in vulnerable patient groups. Therefore, understanding Ad biology and antiviral processes is important to comprehend the signaling cascades during an infection and to initiate appropriate diagnostic and therapeutic interventions. In addition, Ad vector-based vaccines have revealed significant potential in generating robust immune protection and recombinant Ad vectors facilitate efficient gene transfer to treat genetic diseases and are used as oncolytic viruses to treat cancer. Continuous improvements in gene delivery capacity, coupled with advancements in production methods, have enabled widespread application in cancer therapy, vaccine development, and gene therapy on a large scale. This review provides a comprehensive overview of the virus biology, and several aspects of recombinant Ad vectors, as well as the development of Ad vector, are discussed. Moreover, we focus on those Ads that were used in preclinical and clinical applications including regenerative medicine, vaccine development, genome engineering, treatment of genetic diseases, and virotherapy in tumor treatment.

Multivalent Epigraph Hemagglutinin Vaccine Protects against Influenza B Virus in Mice

Influenza B virus is a respiratory pathogen that contributes to seasonal epidemics, accounts for approximately 25% of global influenza infections, and can induce severe disease in young children. While vaccination is the most commonly used method of preventing influenza infections, current vaccines only induce strain-specific responses and have suboptimal efficacy when mismatched from circulating strains. Further, two influenza B virus lineages have been described, B/Yamagata-like and B/Victoria-like, and the limited cross-reactivity between the two lineages provides an additional barrier in developing a universal influenza B virus vaccine. Here, we report a novel multivalent vaccine using computationally designed Epigraph hemagglutinin proteins targeting both the B/Yamagata-like and B/Victoria-like lineages. When compared to the quadrivalent commercial vaccine, the Epigraph vaccine demonstrated increased breadth of neutralizing antibody and T cell responses. After lethal heterologous influenza B virus challenge, mice immunized with the Epigraph vaccine were completely protected against both weight loss and mortality. The superior cross-reactive immunity conferred by the Epigraph vaccine immunogens supports their continued investigation as a universal influenza B virus vaccine.

The role of KLF2 in regulating hepatic lipogenesis and blood cholesterol homeostasis via the SCAP/SREBP pathway

Liver steatosis is a common metabolic disorder resulting from imbalanced lipid metabolism, which involves various processes such as de novo lipogenesis, fatty acid uptake, fatty acid oxidation, and VLDL secretion. In this study, we discovered that KLF2, a transcription factor, plays a crucial role in regulating lipid metabolism in the liver. Overexpression of KLF2 in the liver of db/db mice, C57BL/6J mice, and Cd36-/- mice fed on a normal diet resulted in increased lipid content in the liver. Additionally, transgenic mice (ALB-Klf2) that overexpressed Klf2 in the liver developed liver steatosis after being fed a normal diet. We found that KLF2 promotes lipogenesis by increasing the expression of SCAP, a chaperone that facilitates the activation of SREBP, the master transcription factor for lipogenic gene expression. Our mechanism studies revealed that KLF2 enhances lipogenesis in the liver by binding to the promoter of SCAP and increasing the expression of genes involved in fatty acid synthesis. Reduction of KLF2 expression led to a decrease in SCAP expression and a reduction in the expression of SREBP1 target genes involved in lipogenesis. Overexpression of KLF2 also increased the activation of SREBP2 and the mRNA levels of its downstream target SOAT1. In C57BL/6J mice fed a high-fat diet, overexpression of Klf2 increased blood VLDL secretion, while reducing its expression decreased blood cholesterol levels. Our study emphasizes the novelty that hepatic KLF2 plays a critical role in regulating lipid metabolism through the KLF2/SCAP/SREBPs pathway, which is essential for hepatic lipogenesis and maintaining blood cholesterol homeostasis.

Chemokine Receptor Antagonists Prevent and Reverse Cofilin-Actin Rod Pathology and Protect Synapses in Cultured Rodent and Human iPSC-Derived Neurons

Synapse loss is the principal cause of cognitive decline in Alzheimer's disease (AD) and related disorders (ADRD). Synapse development depends on the intricate dynamics of the neuronal cytoskeleton. Cofilin, the major protein regulating actin dynamics, can be sequestered into cofilactin rods, intra-neurite bundles of cofilin-saturated actin filaments that can disrupt vesicular trafficking and cause synaptic loss. Rods are a brain pathology in human AD and mouse models of AD and ADRD. Eliminating rods is the focus of this paper. One pathway for rod formation is triggered in ~20% of rodent hippocampal neurons by disease-related factors (e.g., soluble oligomers of Amyloid-β (Aβ)) and requires cellular prion protein (PrPC), active NADPH oxidase (NOX), and cytokine/chemokine receptors (CCRs). FDA-approved antagonists of CXCR4 and CCR5 inhibit Aβ-induced rods in both rodent and human neurons with effective concentrations for 50% rod reduction (EC50) of 1-10 nM. Remarkably, two D-amino acid receptor-active peptides (RAP-103 and RAP-310) inhibit Aβ-induced rods with an EC50 of ~1 pM in mouse neurons and ~0.1 pM in human neurons. These peptides are analogs of D-Ala-Peptide T-Amide (DAPTA) and share a pentapeptide sequence (TTNYT) antagonistic to several CCR-dependent responses. RAP-103 does not inhibit neuritogenesis or outgrowth even at 1 µM, >106-fold above its EC50. N-terminal methylation, or D-Thr to D-Ser substitution, decreases the rod-inhibiting potency of RAP-103 by 103-fold, suggesting high target specificity. Neither RAP peptide inhibits neuronal rod formation induced by excitotoxic glutamate, but both inhibit rods induced in human neurons by several PrPC/NOX pathway activators (Aβ, HIV-gp120 protein, and IL-6). Significantly, RAP-103 completely protects against Aβ-induced loss of mature and developing synapses and, at 0.1 nM, reverses rods in both rodent and human neurons (T½ ~ 3 h) even in the continuous presence of Aβ. Thus, this orally available, brain-permeable peptide should be highly effective in reducing rod pathology in multifactorial neurological diseases with mixed proteinopathies acting through PrPC/NOX.

Construction and application of adenoviral vectors

Adenoviral vectors have been widely used as vaccine candidates or potential vaccine candidates against infectious diseases due to the convenience of genome manipulation, their ability to accommodate large exogenous gene fragments, easy access of obtaining high-titer of virus, and high efficiency of transduction. At the same time, adenoviral vectors have also been used extensively in clinical research for cancer gene therapy and treatment of diseases caused by a single gene defect. However, application of adenovirus also faces a series of challenges such as poor targeting, strong immune response against the vector itself, and they cannot be used repeatedly. It is believed that these problems will be solved gradually with further research and technological development in related fields. Here, we review the construction methods of adenoviral vectors, including "gutless" adenovirus and discuss application of adenoviral vectors as prophylactic vaccines for infectious pathogens and their application prospects as therapeutic vaccines for cancer and other kinds of chronic infectious disease such as human papillomavirus, hepatitis B virus, and hepatitis C virus.

Lysyl oxidase inhibits BMP9-induced osteoblastic differentiation through reducing Wnt/β-catenin via HIF-1a repression in 3T3-L1 cells

BACKGROUND

Bone morphogenetic protein 9 (BMP9) is a promising growth factor in bone tissue engineering, while the detailed molecular mechanism underlying BMP9-oriented osteogenesis remains unclear. In this study, we investigated the effect of lysyl oxidase (Lox) on the BMP9 osteogenic potential via in vivo and in vitro experiments, as well as the underlying mechanism.

METHODS

PCR assay, western blot analysis, histochemical staining, and immunofluorescence assay were used to quantify the osteogenic markers level, as well as the possible mechanism. The mouse ectopic osteogenesis assay was used to assess the impact of Lox on BMP9-induced bone formation.

RESULTS

Our findings suggested that Lox was obviously upregulated by BMP9 in 3T3-L1 cells. BMP9-induced Runx2, OPN, and mineralization were all enhanced by Lox inhibition or knockdown, while Lox overexpression reduced their expression. Additionally, the BMP9-induced adipogenic makers were repressed by Lox inhibition. Inhibition of Lox resulted in an increase in c-Myc mRNA and β-catenin protein levels. However, the increase in BMP9-induced osteoblastic biomarkers caused by Lox inhibition was obviously reduced when β-catenin knockdown. BMP9 upregulated HIF-1α expression, which was further enhanced by Lox inhibition or knockdown, but reversed by Lox overexpression. Lox knockdown or HIF-1α overexpression increased BMP9-induced bone formation, although the enhancement caused by Lox knockdown was largely diminished when HIF-1α was knocked down. Lox inhibition increased β-catenin levels and decreased SOST levels, which were almost reversed by HIF-1α knockdown.

CONCLUSION

Lox may reduce the BMP9 osteoblastic potential by inhibiting Wnt/β-catenin signaling via repressing the expression HIF-1α partially.

MMP13 promotes the osteogenic potential of BMP9 by enhancing Wnt/β-catenin signaling via HIF-1α upregulation in mouse embryonic fibroblasts

Bone morphogenetic protein 9 (BMP9) has been validated as one of the most potent osteoinduction factors, but its underlying mechanism remains unclear. As a member of the matrix metalloproteinase (MMP) family, MMP13 may be involved in regulating the lineage-specific differentiation of mouse embryonic fibroblasts (MEFs). The goal of this study was to determine whether MMP13 regulates the osteoinduction potential of BMP9 in MEFs, which are multipotent progenitor cells widely used for stem cell biology research. In vitro and in vivo experiments showed that BMP9-induced osteogenic markers and/or bone were enhanced by exogenous MMP13 in MEFs, but were reduced by MMP13 knockdown or inhibition. The expression of hypoxia inducible factor 1 alpha (HIF-1α) was induced by BMP9, which was enhanced by MMP13. The protein expression of β-catenin and phosphorylation level of glycogen synthase kinase-3 beta (GSK-3β) were increased by BMP9 in MEFs, as was the translocation of β-catenin from the cytoplasm to the nucleus; all these effects of BMP9 were enhanced by MMP13. Furthermore, the MMP13 effects of increasing BMP9-induced β-catenin protein expression and GSK-3β phosphorylation level were partially reversed by HIF-1α knockdown. These results suggest that MMP13 can enhance the osteoinduction potential of BMP9, which may be mediated, at least in part, through the HIF-1α/β-catenin axis. Our findings demonstrate a novel role of MMP13 in the lineage decision of progenitor cells and provide a promising strategy to speed up bone regeneration.

HCMV UL8 interaction with β-catenin and DVL2 regulates viral reactivation in CD34+ hematopoietic progenitor cells

IMPORTANCE

CD34+ hematopoietic progenitor cells (HPCs) are an important cellular reservoir for latent human cytomegalovirus (HCMV). Several HCMV genes are expressed during latency that are involved with the maintenance of the viral genome in CD34+ HPC. However, little is known about the process of viral reactivation in these cells. Here, we describe a viral protein, pUL8, and its interaction and stabilization with members of the Wnt/β-catenin pathway as an important component of viral reactivation. We further define that pUL8 and β-catenin interact with DVL2 via a PDZ-binding domain, and loss of UL8 interaction with β-catenin-DVL2 restricts viral reactivation. Our findings will be instrumental in understanding the molecular processes involved in HCMV reactivation in order to design new antiviral therapeutics.

Hepatic conversion of acetyl-CoA to acetate plays crucial roles in energy stress

Accumulating evidence indicates that acetate is increased under energy stress conditions such as those that occur in diabetes mellitus and prolonged starvation. However, how and where acetate is produced and the nature of its biological significance are largely unknown. We observed overproduction of acetate to concentrations comparable to those of ketone bodies in patients and mice with diabetes or starvation. Mechanistically, ACOT12 and ACOT8 are dramatically upregulated in the liver to convert free fatty acid-derived acetyl-CoA to acetate and CoA. This conversion not only provides a large amount of acetate, which preferentially fuels the brain rather than muscle, but also recycles CoA, which is required for sustained fatty acid oxidation and ketogenesis. We suggest that acetate is an emerging novel 'ketone body' that may be used as a parameter to evaluate the progression of energy stress.

Effectiveness of conjunctival bleb scarring by knock-down of heat shock protein 47 in rat model

AIM

To evaluate the effectiveness of knock-down of heat shock protein 47 (HSP47) on conjunctival bleb scarring in a rat model and its possible mechanism.

METHODS

Male Sprague-Dawley rats were used for glaucoma filtration surgery (GFS) and were treated with either phosphate buffered solution, shControl, mitomycin C, or sh-HSP47 using a microsyringe immediately after GFS. The morphology of filtering blebs was observed postoperatively. The levels of HSP47 were analyzed at 2, 5, 8, and 11d after GFS via real-time quantitative polymerase chain reaction (PCR) and Western blot. The silencing effect of HSP47, the expression of collagen I and III, and the potential signaling pathways of HSP47 during scarification were explored 11d post GFS. The protein levels of transforming growth factor-β1 (TGF-β1), phospho-Smad2 (pSmad2), phospho-Smad3 (p-Smad3), and phospho-p38 (p-p38) were also analyzed using Western blot.

RESULTS

Sh-HSP47 treatment significantly prolonged the functional filtration bleb retention. The levels of HSP47 were increased significantly at 5, 8, and 11d postoperatively compared to the control group (P<0.05, P<0.01, and P<0.001). The levels of HSP47 protein at day 11 postoperatively were significantly down-regulated after HSP47 silencing using sh-HSP47 adenovirus transfection (P<0.01). Expression levels of collagen I and III within the blebs were significantly reduced in the absence of HSP47 (P<0.01). Moreover, the protein levels of TGF-β1, p-Smad2/3, and p-p38 were dramatically inhibited after treatment with sh-HSP47 (P<0.01).

CONCLUSION

The inhibitory effects of HSP47 knock-down on scarring after GFS have the potential to be an efficacious therapeutic option for the treatment of conjunctival bleb scarring.

The Use of Viral Vectors for Gene Therapy and Vaccination in Tuberculosis

Tuberculosis (TB), an infection caused by Mycobacterium tuberculosis (Mtb), is one of the primary causes of death globally. The treatment of TB is long and based on several drugs, producing problems in compliance and toxicity, increasing Mtb resistance to first-line antibiotics that result in multidrug-resistant TB and extensively drug-resistant TB. Thus, the need for new anti-TB treatments has increased. Here, we review some model strategies to study gene therapy based on the administration of a recombinant adenovirus that encodes diverse cytokines, such as IFNγ, IL12, GM/CSF, OPN, TNFα, and antimicrobial peptides to enhance the protective immune response against Mtb. These models include a model of progressive pulmonary TB, a model of chronic infection similar to latent TB, and a murine model of pulmonary Mtb transmission to close contacts. We also review new vaccines that deliver Mtb antigens via particle- or virus-based vectors and trigger protective immune responses. The results obtained in this type of research suggest that this is an alternative therapy that has the potential to treat active TB as an adjuvant to conventional antibiotics and a promising preventive treatment for latent TB reactivation and Mtb transmission. Moreover, Ad vector vaccines are adequate for preventing infectious diseases, including TB.

Role of available COVID-19 vaccines in reducing deaths and perspective for next generation vaccines and therapies to counter emerging viral variants: an update

The COVID-19 disease wreaked havoc all over the world causing more than 6 million deaths out of over 519 million confirmed cases. It not only disturbed the human race health-wise but also caused huge economic losses and social disturbances. The utmost urgency to counter pandemic was to develop effective vaccines as well as treatments that could reduce the incidences of infection, hospitalization and deaths. The most known vaccines that could help in managing these parameters are Oxford-AstraZeneca (AZD1222), Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273) and Johnson & Johnson (Ad26.COV2.S). The effectiveness of AZD1222 vaccine in reducing deaths is 88% in the age group 40-59 years, touching 100% in the age group 16-44 years & 65-84 years. BNT162b2 vaccine also did well in reducing deaths due to COVID-19 (95% in the age group 40-49 years and 100% in the age group 16-44 years. Similarly, mRNA-1273 vaccine showed potential in reducing COVID-19 deaths with effectiveness ranging from 80.3 to 100% depending upon age group of the vaccinated individuals. Ad26.COV2.S vaccine was also 100% effective in reducing COVID-19 deaths. The SARS-CoV-2 emerging variants have emphasized the need of booster vaccine doses to enhance protective immunity in vaccinated individuals. Additionally, therapeutic effectiveness of Molnupiravir, Paxlovid and Evusheld are also providing resistance against the spread of COVID-19 disease as well as may be effective against emerging variants. This review highlights the progress in developing COVID-19 vaccines, their protective efficacies, advances being made to design more efficacious vaccines, and presents an overview on advancements in developing potent drugs and monoclonal antibodies for countering COVID-19 and emerging variants of SARS-CoV-2 including the most recently emerged and highly mutated Omicron variant.

BCG administration promotes the long-term protection afforded by a single-dose intranasal adenovirus-based SARS-CoV-2 vaccine

Recent publications have explored intranasal (i.n.) adenovirus-based (Ad) vaccines as an effective strategy for SARS-CoV-2 in pre-clinical models. However, the effects of prior immunizations and infections have yet to be considered. Here, we investigate the immunomodulatory effects of Mycobacterium bovis BCG pre-immunization followed by vaccination with an S-protein-expressing i.n. Ad, termed Ad(Spike). While i.n. Ad(Spike) retains some protective effect after 6 months, a single administration of BCG-Danish prior to Ad(Spike) potentiates its ability to control viral replication of the B.1.351 SARS-CoV-2 variant within the respiratory tract. Though BCG-Danish did not affect Ad(Spike)-generated humoral immunity, it promoted the generation of cytotoxic/Th1 responses over suppressive FoxP3+ TREG cells in the lungs of infected mice. Thus, this vaccination strategy may prove useful in limiting future pandemics by potentiating the long-term efficacy of mucosal vaccines within the context of the widely distributed BCG vaccine.

A brown fat-enriched adipokine, ASRA, is a leptin receptor antagonist that stimulates appetite

The endocrine control of food intake remains incompletely understood, and whether the leptin receptor-mediated anorexigenic pathway in the hypothalamus is negatively regulated by a humoral factor is unknown. Here we identify an appetite-stimulating factor - ASRA - that acts as a leptin receptor antagonist. ASRA encodes an 8 kD protein that is abundantly and selectively expressed in adipose tissue and to a lesser extent, in liver, and is upregulated during fasting and cold. ASRA protein associates with autophagosomes and its secretion is induced by energy deficiency. Overexpression of ASRA in mice attenuates leptin receptor signaling leading to elevated blood glucose and development of severe hyperphagic obesity, whereas either adipose- or liver-specific ASRA knockout mice display increased leptin sensitivity, improved glucose homeostasis, reduced food intake, and resistance to high fat diet-induced obesity. Furthermore, ASRA is indispensable for cold-evoked feeding response. Recombinant ASRA (rASRA) protein binds to leptin receptor and suppresses leptin receptor signaling in cultured cells. In vivo, rASRA promotes food intake and increases blood glucose in a leptin receptor signaling-dependent manner. Our studies collectively show that ASRA, acting as a peripheral signal of energy deficit, stimulates appetite and regulates glucose metabolism by antagonizing leptin receptor signaling, thus revealing a previously unknown endocrine mechanism that has important implications for our understanding of leptin resistance.

Adenoviral vectors infect B lymphocytes in vivo

B cells are the antibody-producing arm of the adaptive immune system and play a critical role in controlling pathogens. Several groups have now demonstrated the feasibility of using engineered B cells as a therapy, including infectious disease control and gene therapy of serum deficiencies. These studies have largely utilized ex vivo modification of the cells. Direct in vivo engineering would be of utility to the field, particularly in infectious disease control where the infrastructure needs of ex vivo cell modification would make a broad vaccination campaign highly challenging. In this study we demonstrate that engineered adenoviral vectors are capable of efficiently transducing murine and human primary B cells both ex vivo and in vivo. We found that unmodified human adenovirus C5 was capable of infecting B cells in vivo, likely due to interactions between the virus penton base protein and integrins. We further describe vector modification with B cell-specific gene promoters and successfully restrict transgene expression to B cells, resulting in a strong reduction in gene expression from the liver, the main site of human adenovirus C5 infection in vivo.

Peroxiredoxin 5 overexpression decreases oxidative stress and dopaminergic cell death mediated by paraquat

Peroxiredoxins (Prdxs) are thiol-dependent enzymes that scavenge peroxides. Previously, we found that Prdxs were hyperoxidized in a Parkinson's disease model induced by paraquat (PQ), which led to their inactivation, perpetuating reactive oxygen species (ROS) formation. Herein, we evaluated the redox state of the typical 2-Cys-Prx subgroup. We found that PQ induces ROS compartmentalization in different organelles, reflected by the 2-Cys-Prdx hyperoxidation pattern detected by redox eastern blotting. 2-Cys Prdxs are most vulnerable to hyperoxidation, while atypical 2-Cys Peroxiredoxin 5 (Prdx5) is resistant and is expressed in multiple organelles, such as mitochondria, peroxisomes, and cytoplasm. Therefore, we overexpressed human Prdx5 in the dopaminergic SHSY-5Y cell line using the adenoviral vector Ad-hPrdx5. Prdx5 overexpression was confirmed by western blotting and immunofluorescence (IF) and effectively decreased PQ-mediated mitochondrial and cytoplasmic ROS assessed with a mitochondrial superoxide indicator and DHE through IF or flow cytometry. Decreased ROS mediated by Prdx5 in the main subcellular compartments led to overall cell protection against PQ-induced cell death, which was demonstrated by flow cytometry using Annexin V labeling and 7-AAD. Therefore, Prdx5 is an attractive therapeutic target for PD, as its overexpression protects dopaminergic cells from ROS and death, which warrants further experimental animal studies for its subsequent application in clinical trials.

Ube4A maintains metabolic homeostasis and facilitates insulin signaling in vivo

OBJECTIVE

Defining the regulators of cell metabolism and signaling is essential to design new therapeutic strategies in obesity and NAFLD/NASH. E3 ubiquitin ligases control diverse cellular functions by ubiquitination-mediated regulation of protein targets, and thus their functional aberration is associated with many diseases. The E3 ligase Ube4A has been implicated in human obesity, inflammation, and cancer. However, its in vivo function is unknown, and no animal models are available to study this novel protein.

METHODS

A whole-body Ube4A knockout (UKO) mouse model was generated, and various metabolic parameters were compared in chow- and high fat diet (HFD)-fed WT and UKO mice, and in their liver, adipose tissue, and serum. Lipidomics and RNA-Seq studies were performed in the liver samples of HFD-fed WT and UKO mice. Proteomic studies were conducted to identify Ube4A's targets in metabolism. Furthermore, a mechanism by which Ube4A regulates metabolism was identified.

RESULTS

Although the body weight and composition of young, chow-fed WT and UKO mice are similar, the knockouts exhibit mild hyperinsulinemia and insulin resistance. HFD feeding substantially augments obesity, hyperinsulinemia, and insulin resistance in both sexes of UKO mice. HFD-fed white and brown adipose tissue depots of UKO mice have increased insulin resistance and inflammation and reduced energy metabolism. Moreover, Ube4A deletion exacerbates hepatic steatosis, inflammation, and liver injury in HFD-fed mice with increased lipid uptake and lipogenesis in hepatocytes. Acute insulin treatment resulted in impaired activation of the insulin effector protein kinase Akt in liver and adipose tissue of chow-fed UKO mice. We identified the Akt activator protein APPL1 as a Ube4A interactor. The K63-linked ubiquitination (K63-Ub) of Akt and APPL1, known to facilitate insulin-induced Akt activation, is impaired in UKO mice. Furthermore, Ube4A K63-ubiquitinates Akt in vitro.

CONCLUSION

Ube4A is a novel regulator of obesity, insulin resistance, adipose tissue dysfunction and NAFLD, and preventing its downregulation may ameliorate these diseases.

HDAC5 modulates SATB1 transcriptional activity to promote lung adenocarcinoma

BACKGROUND

Dysregulation of histone deacetylases has been linked to diverse cancers. HDAC5 is a histone deacetylase belonging to Class IIa family of histone deacetylases. Limited substrate repertoire restricts the understanding of molecular mechanisms underlying its role in tumorigenesis.

METHODS

We employed a biochemical screen to identify SATB1 as HDAC5-interacting protein. Coimmunoprecipitation and deacetylation assay were performed to validate SATB1 as a HDAC5 substrate. Proliferation, migration assay and xenograft studies were performed to determine the effect of HDAC5-SATB1 interaction on tumorigenesis.

RESULTS

Here we report that HDAC5 binds to and deacetylates SATB1 at the conserved lysine 411 residue. Furthermore, dynamic regulation of acetylation at this site is determined by TIP60 acetyltransferase. We also established that HDAC5-mediated deacetylation is critical for SATB1-dependent downregulation of key tumor suppressor genes. Deacetylated SATB1 also represses SDHA-induced epigenetic remodeling and anti-proliferative transcriptional program. Thus, SATB1 spurs malignant phenotype in a HDAC5-dependent manner.

CONCLUSIONS

Our study highlights the pivotal role of HDAC5 in tumorigenesis. Our findings provide key insights into molecular mechanisms underlying SATB1 promoted tumor growth and metastasis.

Rapid Construction of an Infectious Clone of Fowl Adenovirus Serotype 4 Isolate

Adenovirus vectors possess a good safety profile, an extensive genome, a range of host cells, high viral yield, and the ability to elicit broad humoral and cellular immune responses. Adenovirus vectors are widely used in infectious disease research for future vaccine development and gene therapy. In this study, we obtained a fowl adenovirus serotype 4 (FAdV-4) isolate from sick chickens with hepatitis-hydropericardium syndrome (HHS) and conducted animal regression text to clarify biological pathology. We amplified the transfer vector and extracted viral genomic DNA from infected LMH cells, then recombined the mixtures via the Gibson assembly method in vitro and electroporated them into EZ10 competent cells to construct the FAdV-4 infectious clone. The infectious clones were successfully rescued in LMH cells within 15 days of transfection. The typical cytopathic effect (CPE) and propagation titer of FAdV-4 infectious clones were also similar to those for wild-type FAdV-4. To further construct the single-cycle adenovirus (SC-Ad) vector, we constructed SC-Ad vectors by deleting the gene for IIIa capsid cement protein. The FAdV4 infectious clone vector was introduced into the ccdB cm expression cassette to replace the IIIa gene using a λ-red homologous recombination technique, and then the ccdB cm expression cassette was excised by PmeI digestion and self-ligation to obtain the resulting plasmids as SC-Ad vectors.

Metabolic regulation of CTCF expression and chromatin association dictates starvation response in mice and flies

Coordinated temporal control of gene expression is essential for physiological homeostasis, especially during metabolic transitions. However, the interplay between chromatin architectural proteins and metabolism in regulating transcription is less understood. Here, we demonstrate a conserved bidirectional interplay between CTCF (CCCTC-binding factor) expression/function and metabolic inputs during feed-fast cycles. Our results indicate that its loci-specific functional diversity is associated with physiological plasticity in mouse hepatocytes. CTCF differential expression and long non-coding RNA-Jpx mediated changes in chromatin occupancy, unraveled its paradoxical yet tuneable functions, which are governed by metabolic inputs. We illustrate the key role of CTCF in controlling temporal cascade of transcriptional response, with effects on hepatic mitochondrial energetics and lipidome. Underscoring the evolutionary conservation of CTCF-dependent metabolic homeostasis, CTCF knockdown in flies abrogated starvation resistance. In summary, we demonstrate the interplay between CTCF and metabolic inputs that highlights the coupled plasticity of physiological responses and chromatin function.

Architectural basis for cylindrical self-assembly governing Plk4-mediated centriole duplication in human cells

Proper organization of intracellular assemblies is fundamental for efficient promotion of biochemical processes and optimal assembly functionality. Although advances in imaging technologies have shed light on how the centrosome is organized, how its constituent proteins are coherently architected to elicit downstream events remains poorly understood. Using multidisciplinary approaches, we showed that two long coiled-coil proteins, Cep63 and Cep152, form a heterotetrameric building block that undergoes a stepwise formation into higher molecular weight complexes, ultimately generating a cylindrical architecture around a centriole. Mutants defective in Cep63•Cep152 heterotetramer formation displayed crippled pericentriolar Cep152 organization, polo-like kinase 4 (Plk4) relocalization to the procentriole assembly site, and Plk4-mediated centriole duplication. Given that the organization of pericentriolar materials (PCM) is evolutionarily conserved, this work could serve as a model for investigating the structure and function of PCM in other species, while offering a new direction in probing the organizational defects of PCM-related human diseases.

Simultaneous Expression of Chicken Granulocyte Monocyte Colony-Stimulating Factor and the Hemagglutinin-Neuraminidase Epitope of the Virulent Newcastle Disease Virus Genotype VII C22 Strain in a Functional Synthetic Recombinant Adenovirus as a Genotype-Matched Vaccine with Potential Antiviral Activity

When it comes to the prevention of clinical signs and mortality associated with infection of the Newcastle disease virus (NDV), vaccination has been very effective. However, recent evidence has proven that more highly virulent strains are emerging that bypass existing immune protection and pose a serious threat to the global poultry industry. Here, a novel rescued adenovirus 5-coexpressed chicken granulocyte monocyte colony-stimulating factor (ChGM-CSF) bio-adjuvant and C22-hemagglutinin-neuraminidase (HN) boosted chickens' immunological genetic resistance and thus improved the immunological effectiveness of the critical new-generation vaccine in vitro and in vivo. Accordingly, the hemagglutination inhibition (HI) titers (log2) of the recombinant adenovirus (rAdv)-ChGM-CSF-HN-immunized chickens had greater, more persistent, and longer-lasting NDV-specific antibodies than the La Sota and rAdv-HN-inoculated birds. Moreover, humoral and adaptive immunological conditions were shown to be in harmony after rAdv-ChGM-CSF-HN inoculation and uniformly enhanced the expression of alpha interferon (IFN-α), IFN-β, IFN-γ, interleukin-1β (IL-1β), IL-2, IL-16, IL-18, and IL-22. Postchallenge, the control challenge (CC), wild-type adenovirus (wtAdv), and rAdv-ChGM-CSF groups developed unique NDV clinical manifestations, significant viral shedding, high tissue viral loads, gross and microscopic lesions, and 100% mortality within 7 days. The La Sota, rAdv-HN, and rAdv-ChGM-CSF-HN groups were healthy and had 100% survival rates. The rAdv-ChGM-CSF-HN group swiftly regulated and stopped viral shedding and had lower tissue viral loads than all groups at 5 days postchallenge (dpc). Thus, the antiviral activity of ChGM-CSF offered robust immune protection in the face of challenge and reduced viral replication convincingly. Our advance innovation concepts, combining ChGM-CSF with a field-circulating strain epitope, could lead to the development of a safe, genotype-matched, universal transgenic vaccine that could eradicate the disease globally, reducing poverty and food insecurity. IMPORTANCE We studied the biological characterization of the developed functional synthetic recombinant adenoviruses, which showed a high degree of safety, thermostability, and genetic stability for up to 20 passages. It was demonstrated through both in vitro and in vivo testing that the immunogenicity of the proposed vaccine, which uses the T2A peptide from the Thosea asigna virus capsid protein supported by glycine and serine, helps with efficiency to generate a multicistronic vector, enables expression of two functional proteins in rAdv-ChGM-CSF-HN, and is superior to that of comparable vaccines. Additionally, adenovirus can be used to produce vaccines matching the virulent field-circulating strain epitope. Because there is no preexisting human adenoviral immunity detected in animals, the potency of adenoviral vaccines looks promising. Also, it ensures that the living vector does not carry the resistance gene that codes for the kanamycin antibiotic. Accordingly, a human recombinant adenoviral vaccine that has undergone biological improvements is beneficial and important.

BMP9 promotes autophagy and inhibits migration and invasion in breast cancer cells through the c-Myc/SNHG3/mTOR signaling axis

We previously reported that BMP9 inhibited breast cancer progression. However, the precise molecular mechanism is still unknown. Based on our RNA-sequencing (RNA-seq) results, BMP9 significantly down-regulated the expression of long non-coding RNA SNHG3. Exogenous BMP9 promoted autophagy and inhibited migration and invasion in MDA-MB-231 cells, which was effectively blunted by SNHG3 overexpression. Interestingly, SNHG3 was negatively connected with autophagy. Knockdown of SNHG3 induced autophagy by increasing the formation of autophagic vacuoles and thus inhibited the migration and invasion of MDA-MB-231 cells. Mechanically, BMP9-SNHG3 activated AMPK, AKT and mTOR signaling pathways to induce autophagy and inhibit migration and invasion. Meanwhile, BMP9 regulated SNHG3 transcription by suppressing c-Myc entry into the nucleus. In conclusion, BMP9 promotes autophagy and inhibits migration and invasion in breast cancer cells through the c-Myc/SNHG3/mTOR signaling axis, which might offer a fresh perspective on BMP9's breast cancer-inhibiting properties.

Virus-free transfection, transient expression, and purification of human cardiac myosin in mammalian muscle cells for biochemical and biophysical assays

Myosin expression and purification is important for mechanistic insights into normal function and mutation induced changes. The latter is particularly important for striated muscle myosin II where mutations cause several debilitating diseases. However, the heavy chain of this myosin is challenging to express and the standard protocol, using C2C12 cells, relies on viral infection. This is time and work intensive and associated with infrastructural demands and biological hazards, limiting widespread use and hampering fast generation of a wide range of mutations. We here develop a virus-free method to overcome these challenges. We use this system to transfect C2C12 cells with the motor domain of the human cardiac myosin heavy chain. After optimizing cell transfection, cultivation and harvesting conditions, we functionally characterized the expressed protein, co-purified with murine essential and regulatory light chains. The gliding velocity (1.5-1.7 µm/s; 25 °C) in the in vitro motility assay as well as maximum actin activated catalytic activity (kcat; 8-9 s-1) and actin concentration for half maximal activity (KATPase; 70-80 µM) were similar to those found previously using virus based infection. The results should allow new types of studies, e.g., screening of a wide range of mutations to be selected for further characterization.

Application of a split-Cre system for high-capacity adenoviral vector amplification

BACKGROUND AND AIMS

High-capacity adenoviral vectors (HC-AdV) show extended DNA payload and stability of gene expression in vivo due to the absence of viral coding sequences. However, production requires methods to trans-complement viral proteins, usually through Helper Viruses (HV). The Cre/loxP system is frequently employed to remove the packaging signal in HV genomes, in order to avoid their encapsidation. However, chronic exposure to the Cre recombinase in packaging cells is detrimental. We have applied the dimerizable Cre system to overcome this limitation.

METHODS AND RESULTS

Cre was split in two fragments devoid of recombinase function (N-terminal 244 and C-terminal 99 amino-acids). In one version of the system, interaction with both moieties was favored by rapamycin-dependent heterodimerization domains (DiCre). Other version contained only Cre sequences (oCre). We generated packaging cells and HVs expressing the complementary fragments and studied their performance for HC-AdV production. We found that both conformations avoided interference with the growth of packaging cells, and the oCre system was particularly suitable for HC-AdV amplification.

CONCLUSIONS

The split-Cre system improves the performance of packaging cells and can reduce the time and cost of HC-AdV amplification up to 30% and 15%, respectively. This may contribute to the standardization of HC-AdV production.

PI3K-Akt signaling regulates BMP2-induced osteogenic differentiation of mesenchymal stem cells (MSCs): A transcriptomic landscape analysis

Bone morphogenetic protein 2 (BMP2) effectively induced mesenchymal stem cells (MSCs) osteogenic differentiation hold great potential for bone tissue engineering. However, a global mechanistic view of BMP2-induced osteogenic differentiation of MSCs remains to be fully elucidated. Here, human umbilical cord-derived MSCs (UC-MSCs) were induced with BMP2, three days and five days later, total RNA were extracted and subjected to RNA-sequencing (RNA-Seq) followed with bioinformatic analysis. Osteogenic differentiation abilities were evaluated with Alkaline phosphatase (ALP) staining and osteogenic differentiation marker expression at both mRNA and protein levels. We identified that adenoviral vectors effectively transduced in UC-MSCs and expressed BMP2 in high efficiency. Both on day 3 and day 5, differentially expressed genes (DEGs) were highly enriched in PI3K-Akt signaling pathway. As for the common DEGs among total BMP2 group vs control group, BMP2 (day 3) versus control (day 3) and BMP2 (day 5) versus control (day 5), there were 105 DGEs and highly enriched in PI3K-Akt signaling pathway. Finally, we found that PI3K-Akt signaling inhibitor dramatically inhibited BMP2-iduced osteogenic differentiation of UC-MSCs. We firstly identified that PI3K-Akt signaling pathway plays a pivotal role in BMP2-induced osteogenic differentiation of MSCs, which may apply a new perspective for BMP2 based bone tissue engineering.

Metabolic regulation of the proteasome under hypoxia by Poldip2 controls fibrotic signaling in vascular smooth muscle cells

The polymerase delta interacting protein 2 (Poldip2) is a nuclear-encoded mitochondrial protein required for oxidative metabolism. Under hypoxia, Poldip2 expression is repressed by an unknown mechanism. Therefore, low levels of Poldip2 are required to maintain glycolytic metabolism. The Cellular Communication Network Factor 2 (CCN2, Connective tissue growth factor, CTGF) is a profibrogenic molecule highly expressed in cancer and vascular inflammation in advanced atherosclerosis. Because CCN2 is upregulated under hypoxia and is associated with glycolytic metabolism, we hypothesize that Poldip2 downregulation is responsible for the upregulation of profibrotic signaling under hypoxia. Here, we report that Poldip2 is repressed under hypoxia by a mechanism that requires the activation of the enhancer of zeste homolog 2 repressive complex (EZH2) downstream from the Cyclin-Dependent Kinase 2 (CDK2). Importantly, we found that Poldip2 repression is required for CCN2 expression downstream of metabolic inhibition of the ubiquitin-proteasome system (UPS)-dependent stabilization of the serum response factor. Pharmacological or gene expression inhibition of CDK2 under hypoxia reverses Poldip2 downregulation, the inhibition of the UPS, and the expression of CCN2, collagen, and fibronectin. Thus, our findings connect cell cycle regulation and proteasome activity to mitochondrial function and fibrotic responses under hypoxia.

lncRNA MEG3 Promotes PDK4/GSK-3β/β-Catenin Axis in MEFs by Targeting miR-532-5p

Studies reported the positive and negative osteogenic effects of MEG3 in mesenchymal stem cells (MSCs). This study aims at clarifying the osteogenic potential of MEG3 and the underlying mechanism. Bone morphogenetic protein 9- (BMP9-) transfected MSCs were recruited as an osteogenic model in vitro, and ectopic bone formation were used in vivo to explore the effect of MEG3 on osteogenesis. We found that overexpression of MEG3 facilitated BMP9-induced osteogenic markers, ALP activities, and matrix mineralization. However, knockdown of MEG3 attenuated BMP9-induced osteogenic markers. MEG3 increased the phosphorylation of GSK-3β and the protein level of β-catenin. Pyruvate dehydrogenase kinase 4 (PDK4) can also combine with GSK-3β and increase the latter phosphorylation. Moreover, MEG3 increased the mRNA level of PDK4. The ceRNA analysis showed that MEG3 may regulate the expression of PDK4 via microRNA 532-5p (miR-532-5p). The MEG3-enhanced GSK-3β/β-catenin axis can be attenuated by miR-532-5p, and miR-532-5p inhibitor partly rescued endogenous PDK4 and MEG3-mediated expression of PDK4. MEG3 may potentiate PDK4 and GSK-3β/β-catenin by inhibiting miR-532-5p.

Regulation of Ferroptosis by Transcription Factor E2F1 and RB

Tumor suppressor RB binds to E2F family proteins and modulates cell cycle progression. Cyclin dependent kinases (CDK) regulate the interaction of RB/E2F by phosphorylating RB. Previously, we have revealed that CDK2, RB and E2F inhibit ferroptosis. Ferroptosis is a non-apoptotic, iron-dependent form of cell death characterized by toxic lipid peroxidation. Here we provide evidence that CDK2 suppresses ferroptosis through phosphorylation of RB. We approach this question by overexpressing WT-RB or a mutant RB that cannot be phosphorylated by CDKs (RBΔCDK) along with CDK2/cyclinE followed by analysis of ferroptosis. We also observed that E2F1 regulates of both pro and anti-ferroptotic proteins including ALOX5, MYC SLC7A11, ATF4, and GPX4 and finally renders a net inhibitory role in ferroptosis. Interestingly, we also found a cell type dependent compensatory effect of E2F3 upon E2F1 depletion. This compensatory effect resulted in no change of ferroptotic target genes after E2F1 knock down in an osteosarcoma cell line. Taken together, our study reveals that cancer cells protect themselves from ferroptosis through cell cycle regulatory proteins.

Adenovirus vector-mediated single chain variable fragments target the nucleocapsid protein of porcine epidemic diarrhea virus and protect against viral infection in piglets

Porcine epidemic diarrhea virus (PEDV) mainly infects the intestinal epithelial cells of pigs, causing porcine epidemic diarrhea (PED). In particular, the virus causes severe diarrhea, dehydration, and death in neonatal piglets. Maternal immunity effectively protects neonatal piglets from PEDV infection; however, maternal antibodies can only prevent PEDV attachment and entry into target cells, but have no effects on intracellular viruses. Intracellular antibodies targeting virus-encoded proteins are effective in preventing viral infection. We previously identified four single chain variable fragments (scFvs), ZW1-16, ZW3-21, ZW1-41, and ZW4-16, which specifically targeted the PEDV N protein and significantly inhibited PEDV replication and up-regulated interferon-λ1 (IFN-λ1) expression in host cells. In our current study, the four scFvs were subcloned into replication-defective adenovirus vectors to generate recombinant adenoviruses rAdV-ZW1-16, rAdV-ZW3-21, rAdV-ZW1-41, and rAdV-ZW4-16. ScFvs were successfully expressed in Human Embryonic Kidney 293 (HEK293) cells and intestinal porcine epithelial cell line J2 (IPEC-J2) and were biosafe for piglets as indicated by body temperature and weight, scFv excretion in feces, IFN-γ and interleukin-4 (IL-4) expression in jejunum, and pathological changes in porcine tissue after oral administration. Western blotting, immunofluorescence, and immunohistochemical analyses showed that scFvs were expressed in porcine jejunum. The prophylactic effects of rAdV-ZW, a cocktail of the four rAdV-scFvs, on piglet diarrhea caused by PEDV was investigated. Clinical symptoms in piglets orally challenged with PEDV, following a two-time treatment with rAdV-ZW, were significantly reduced when compared with PEDV-infected piglets treated with phosphate buffered saline (PBS) or rAdV-wild-type. Also, no death and jejunal lesions were observed. ScFv co-localization with the PEDV N protein in vivo was also observed. Next, the expression of pro-inflammatory serum cytokines such as tumor necrosis factor-α (TNF-α), IL-6, IL-8, IL-12, and IFN-λ was assessed by enzyme-linked immunosorbent assay (ELISA), which showed that scFvs significantly suppressed PEDV-induced pro-inflammatory cytokine expression and restored PEDV-inhibited IFN-λ expression. Therefore, our study supported a promising role for intracellular scFvs targeting the PEDV N protein to prevent and treat diarrhea in PEDV-infected piglets.

The effect of BMP9 on inflammation in the early stage of pulpitis

BACKGROUND

Bone morphogenetic protein 9 (BMP9) tends to be associated with various inflammatory responses of diseases, but its relationship with pulpitis remains unknown.

OBJECTIVE

This study aimed to evaluate the effects and mechanisms of BMP9 in pulpitis.

METHODOLOGY

A rat model of pulpitis was used to evaluate the expression of BMP9, which was also analysed in Porphyromonas gingivalis lipopolysaccharide (Pg-LPS)-stimulated human dental pulp cells (hDPCs). The effects and mechanism of BMP9 on the regulation of inflammatory factors and matrix metalloproteinase-2 (MMP2) were evaluated using real-time quantitative PCR, western blotting, and immunocytofluorescence. Moreover, the migration ability of THP-1 monocyte-macrophages, treated with inflammatory supernate inhibited by BMP9, was previously tested by a transwell migration assay. Finally, a direct rat pulp capping model was used to evaluate in vivo the influence of the overexpression of BMP9 in pulpitis.

RESULTS

The expression of BMP9 decreased after 24 h and increased after 3 and 7 d in rat pulpitis and inflammatory hDPCs. The overexpression of BMP9 inhibited the gene expression of inflammatory factors (IL-6, IL-8, and CCL2) and the secretion of IL-6 and MMP2 in Pg-LPS-stimulated hDPCs. The level of phosphorylated Smad1/5 was upregulated and the levels of phosphorylated ERK and JNK were downregulated. The inflammatory supernate of hDPCs inhibited by BMP9 reduced the migration of THP-1 cells. In rat pulp capping models, overexpressed BMP9 could partially restrain the development of dental pulp inflammation.

CONCLUSION

This is the first study to confirm that BMP9 is involved in the occurrence and development of pulpitis and can partially inhibit its severity in the early stage. These findings provided a theoretical reference for future studies on the mechanism of pulpitis and application of bioactive molecules in vital pulp therapy.

Matricellular Protein SMOC2 Potentiates BMP9-Induced Osteogenic Differentiation in Mesenchymal Stem Cells through the Enhancement of FAK/PI3K/AKT Signaling

Mesenchymal stem cells (MSCs) can self-renew and differentiate into multiple lineages, making MSC transplantation a promising option for bone regeneration. Both matricellular proteins and growth factors play an important role in regulating stem cell fate. In this study, we investigated the effects of matricellular protein SMOC2 (secreted modular calcium-binding protein 2) on bone morphogenetic protein 9 (BMP9) in mouse embryonic fibroblasts (MEFs) and revealed a possible molecular mechanism underlying this process. We found that SMOC2 was detectable in MEFs and that exogenous SMOC2 expression potentiated BMP9-induced osteogenic markers, matrix mineralization, and ectopic bone formation, whereas SMOC2 knockdown inhibited these effects. BMP9 increased the levels of p-FAK and p-AKT, which were either enhanced or reduced by SMOC2 and FAK silencing, respectively. BMP9-induced osteogenic markers were increased by SMOC2, and this increase was partially abolished by silencing FAK or LY290042. Furthermore, we found that general transcription factor 2I (GTF2I) was enriched at the promoter region of SMOC2 and that integrin β1 interacted with SMOC2 in BMP9-treated MEFs. Our findings demonstrate that SMOC2 can promote BMP9-induced osteogenic differentiation by enhancing the FAK/PI3K/AKT pathway, which may be triggered by facilitating the interaction between SMOC2 and integrin β1.

Double-modified oncolytic adenovirus armed with a recombinant interferon-like gene enhanced abscopal effects against malignant glioma

Background

The development of new therapies for malignant gliomas has been stagnant for decades. Through the promising outcomes in clinical trials of oncolytic virotherapy, there is now a glimmer of hope in addressing this situation. To further enhance the antitumor immune response of oncolytic viruses, we have equipped a modified oncolytic adenovirus (oAds) with a recombinant interferon-like gene (YSCH-01) and conducted a comprehensive evaluation of the safety and efficacy of this modification compared to existing treatments.

Methods

To assess the safety of YSCH-01, we administered the oAds intracranially to Syrian hamsters, which are susceptible to adenovirus. The efficacy of YSCH-01 in targeting glioma was evaluated through in vitro and in vivo experiments utilizing various human glioma cell lines. Furthermore, we employed a patient-derived xenograft model of recurrent glioblastoma to test the effectiveness of YSCH-01 against temozolomide.

Results

By modifying the E1A and adding survivin promoter, the oAds have demonstrated remarkable safety and an impressive ability to selectively target tumor cells. In animal models, YSCH-01 exhibited potent therapeutic efficacy, particularly in terms of its distant effects. Additionally, YSCH-01 remains effective in inhibiting the recurrent GBM patient-derived xenograft model.

Conclusions

Our initial findings confirm that a double-modified oncolytic adenovirus armed with a recombinant interferon-like gene is both safe and effective in the treatment of malignant glioma. Furthermore, when utilized in combination with a targeted therapy gene strategy, these oAds exhibit a more profound effect in tumor therapy and an enhanced ability to inhibit tumor growth at remote sites.

Mucosal immunization with Ad5-based vaccines protects Syrian hamsters from challenge with omicron and delta variants of SARS-CoV-2

SARS-CoV-2 variant clades continue to circumvent antibody responses elicited by vaccination or infection. Current parenteral vaccination strategies reduce illness and hospitalization, yet do not significantly protect against infection by the more recent variants. It is thought that mucosal vaccination strategies may better protect against infection by inducing immunity at the sites of infection, blocking viral transmission more effectively, and significantly inhibiting the evolution of new variants of concern (VOCs). In this study, we evaluated the immunogenicity and efficacy of a mucosally-delivered, non-replicating, adenovirus type 5-vectored vaccine that expresses the spike (S) gene of Wuhan (rAd5-S-Wuhan), delta (rAd5-S-delta), or omicron (rAd5-S-omicron) SARS-CoV-2 VOCs. Hamsters were immunized with these vaccines intranasally prior to challenge with omicron or delta variants. Additionally, one group was vaccinated by oral gavage with rAd5-S-Wuhan prior to challenge with the delta variant. Both intranasal and oral administration of rAd5-S-Wuhan generated cross-reactive serum IgG and mucosal IgA to all variant spike and RBD proteins tested. rAd5-S-omicron and rAd5-S-delta additionally elicited cross-reactive antibodies, though rAd5-S-omicron had significantly lower binding antibody levels except against its matched antigens. Two weeks after the final vaccination, hamsters were challenged with a SARS-CoV-2 variant; omicron or delta. Whether matched to the challenge or with rAd5-S-Wuhan, all vaccines protected hamsters from weight loss and lung pathology caused by challenge and significantly reduced viral shedding compared to placebo. Vaccination with rAd5-S-Wuhan provided significant protection, although there was an improved reduction in shedding and disease pathology in groups protected by the matched VOC vaccines. Nevertheless, Wuhan-based vaccination elicited the most cross-reactive antibody responses generally. Overall, heterologous vaccination via mucosal routes may be advantageous for second-generation vaccines.

Hepatic PTP4A1 ameliorates high-fat diet-induced hepatosteatosis and hyperglycemia by the activation of the CREBH/FGF21 axis

Precise regulation of kinases and phosphatases is crucial for human metabolic homeostasis. This study aimed to investigate the roles and molecular mechanisms of protein tyrosine phosphatase type IVA1 (PTP4A1) in regulating hepatosteatosis and glucose homeostasis. Method: Ptp4a1^-/- mice, adeno-associated virus encoding Ptp4a1 under liver-specific promoter, adenovirus encoding Fgf21, and primary hepatocytes were used to evaluate PTP4A1-mediated regulation in the hepatosteatosis and glucose homeostasis. Glucose tolerance test, insulin tolerance test, 2-deoxyglucose uptake assay, and hyperinsulinemic-euglycemic clamp were performed to estimate glucose homeostasis in mice. The staining, including oil red O, hematoxylin & eosin, and BODIPY, and biochemical analysis for hepatic triglycerides were performed to assess hepatic lipids. Luciferase reporter assays, immunoprecipitation, immunoblots, quantitative real-time polymerase chain reaction, and immunohistochemistry staining were conducted to explore the underlying mechanism. Results: Here, we found that deficiency of PTP4A1 aggravated glucose homeostasis and hepatosteatosis in mice fed a high-fat (HF) diet. Increased lipid accumulation in hepatocytes of Ptp4a1^-/- mice reduced the level of glucose transporter 2 on the plasma membrane of hepatocytes leading to a diminution of glucose uptake. PTP4A1 prevented hepatosteatosis by activating the transcription factor cyclic adenosine monophosphate-responsive element-binding protein H (CREBH)/fibroblast growth factor 21 (FGF21) axis. Liver-specific PTP4A1 or systemic FGF21 overexpression in Ptp4a1^-/- mice fed an HF diet restored the disorder of hepatosteatosis and glucose homeostasis. Finally, liver-specific PTP4A1 expression ameliorated an HF diet-induced hepatosteatosis and hyperglycemia in wild-type mice. Conclusions: Hepatic PTP4A1 is critical for regulating hepatosteatosis and glucose homeostasis by activating the CREBH/FGF21 axis. Our current study provides a novel function of PTP4A1 in metabolic disorders; hence, modulating PTP4A1 may be a potential therapeutic strategy against hepatosteatosis-related diseases.

Pyruvate dehydrogenase kinase 4 promotes osteoblastic potential of BMP9 by boosting Wnt/β-catenin signaling in mesenchymal stem cells

Bone morphogenetic protein 9 (BMP9) is an effective osteogenic factor and a promising candidate for bone tissue engineering. The osteoblastic potential of BMP9 needs to be further increased to overcome its shortcomings. However, the details of how BMP9 triggers osteogenic differentiation in mesenchymal stem cells (MSCs) are unclear. In this study, we used real-time PCR, western blot, histochemical staining, mouse ectopic bone formation model, immunofluorescence, immunoprecipitation, and chromatin immunoprecipitation to investigate the role of pyruvate dehydrogenase kinase 4 (PDK4) in BMP9-induced osteogenic differentiation of C3H10T1/2 cells, as well as the underlying mechanism. We found that PDK4 was upregulated by BMP9 in C3H10T1/2 cells. BMP9-induced osteogenic markers and bone mass were increased by PDK4 overexpression, but decreased by PDK4 silencing. β-catenin protein level was increased by BMP9, which was enhanced by PDK overexpression and decreased by PDK4 silencing. BMP9-induced osteogenic markers were reduced by PDK4 silencing, which was almost reversed by β-catenin overexpression. PDK4 increased the BMP9-induced osteogenic markers, which was almost eliminated by β-catenin silencing. Sclerostin was mildly decreased by BMP9 or PDK4, and significantly decreased by combined BMP9 and PDK4. In contrast, sclerostin increased significantly when BMP9 was combined with PDK4 silencing. BMP9-induced p-SMAD1/5/9 was increased by PDK4 overexpression, but was reduced by PDK4 silencing. PDK4 interacts with p-SMAD1/5/9 and regulates the sclerostin promoter. These findings suggest that PDK4 can increase the osteogenic potential of BMP9 by enhancing Wnt/β-catenin signaling via the downregulation of sclerostin. PDK4 may be an effective target to strengthen BMP9-induced osteogenesis.

TAZ promotes osteogenic differentiation of mesenchymal stem cells line C3H10T1/2, murine multi-lineage cells lines C2C12, and MEFs induced by BMP9

Bone morphogenetic protein 9 (BMP9), also named as growth differentiation factor 2 (GDF-2), is the strongest cytokine that promotes osteogenic differentiation in the BMP family, and has broad clinical application value. Nevertheless, the mechanism of BMP9 promotes osteogenic differentiation remain unclear. TAZ, a transcriptional co-activator, has great effects on cell proliferation, differentiation, and stem cell self-renewal. In this research, we investigated the effects of TAZ in BMP9-induced osteogenic differentiation of mesenchymal stem cell line C3H10T1/2 (MSCs) and murine multi-lineage cell lines C2C12 and MEFs (MMCs) and explored its possible mechanisms. This study has found that BMP9 induces the expression of TAZ and promotes its nuclear translocation. Meanwhile, our study found that Ad-TAZ and TM-25659, a TAZ agonist, can enhance the osteogenic differentiation of MSCs and MMCs induced by BMP9. Conversely, Ad-si-TAZ and verteporfin, an inhibitor of TAZ, have the contradictory effect. Likewise, the promotion of TAZ to the BMP9-induced ectopic bone formation in vivo was confirmed by the subcutaneous transplantation of MSCs in nude mice. Furthermore, we have detected that TAZ might increase the levels of the phosphorylation of Smad1/5/8, p38, ERK1/2, and JNK induced by BMP9. Additionally, we also found that TAZ increased the total protein level of β-catenin induced by BMP9. In summary, our results strongly indicated that TAZ will promote the osteogenic differentiation in MSCs and MMCs induced by BMP9 through multiple signal pathways.

High-Level rAAV Vector Production by rAdV-Mediated Amplification of Small Amounts of Input Vector

The successful application of recombinant adeno-associated virus (rAAV) vectors for long-term transgene expression in clinical studies requires scalable production methods with genetically stable components. Due to their simple production scheme and the high viral titers achievable, first generation recombinant adenoviruses (rAdV) have long been taken into consideration as suitable tools for simultaneously providing both the helper functions and the AAV rep and cap genes for rAAV packaging. So far, however, such rAdV-rep/cap vectors have been difficult to generate and often turned out to be genetically unstable. Through ablation of cis and trans inhibitory function in the AAV-2 genome we have succeeded in establishing separate and stable rAdVs for high-level AAV serotype 2 Rep and Cap expression. These allowed rAAV-2 production at high burst sizes by simple coinfection protocols after providing the AAV-ITR flanked transgene vector genome either as rAAV-2 particles at low input concentrations or in form of an additional rAdV. With characteristics such as the ease of producing the required components, the straightforward adaption to other transgenes and the possible extension to further serotypes or capsid variants, especially the rAdV-mediated rAAV amplification system presents a very promising candidate for up-scaling to clinical grade vector preparations.

A brown fat-enriched adipokine Adissp controls adipose thermogenesis and glucose homeostasis

The signaling mechanisms underlying adipose thermogenesis have not been fully elucidated. Particularly, the involvement of adipokines that are selectively expressed in brown adipose tissue (BAT) and beige adipocytes remains to be investigated. Here we show that a previously uncharacterized adipokine (UPF0687 protein / human C20orf27 homolog) we named as Adissp (Adipose-secreted signaling protein) is a key regulator for white adipose tissue (WAT) thermogenesis and glucose homeostasis. Adissp expression is adipose-specific and highly BAT-enriched, and its secretion is stimulated by β3-adrenergic activation. Gain-of-functional studies collectively showed that secreted Adissp promotes WAT thermogenesis, improves glucose homeostasis, and protects against obesity. Adipose-specific Adissp knockout mice are defective in WAT browning, and are susceptible to high fat diet-induced obesity and hyperglycemia. Mechanistically, Adissp binds to a putative receptor on adipocyte surface and activates protein kinase A independently of β-adrenergic signaling. These results establish BAT-enriched Adissp as a major upstream signaling component in thermogenesis and offer a potential avenue for the treatment of obesity and diabetes.