Peroxiredoxin 3 deficiency induces cardiac hypertrophy and dysfunction by impaired mitochondrial quality control.

Mitochondrial quality control (MQC) consists of multiple processes: the prevention of mitochondrial oxidative damage, the elimination of damaged mitochondria via mitophagy and mitochondrial fusion and fission. Several studies proved that MQC impairment causes a plethora of pathological conditions including cardiovascular diseases. However, the precise molecular mechanism by which MQC reverses mitochondrial dysfunction, especially in the heart, is unclear. The mitochondria-specific peroxidase Peroxiredoxin 3 (Prdx3) plays a protective role against mitochondrial dysfunction by removing mitochondrial reactive oxygen species. Therefore, we investigated whether Prdx3-deficiency directly leads to heart failure via mitochondrial dysfunction. Fifty-two-week-old Prdx3-deficient mice exhibited cardiac hypertrophy and dysfunction with giant and damaged mitochondria. Mitophagy was markedly suppressed in the hearts of Prdx3-deficient mice compared to the findings in wild-type and Pink1-deficient mice despite the increased mitochondrial damage induced by Prdx3 deficiency. Under conditions inducing mitophagy, we identified that the damaged mitochondrial accumulation of PINK1 was completely inhibited by the ablation of Prdx3. We propose that Prdx3 interacts with the N-terminus of PINK1, thereby protecting PINK1 from proteolytic cleavage in damaged mitochondria undergoing mitophagy. Our results provide evidence of a direct association between MQC dysfunction and cardiac function. The dual function of Prdx3 in mitophagy regulation and mitochondrial oxidative stress elimination further clarifies the mechanism of MQC in vivo and thereby provides new insights into developing a therapeutic strategy for mitochondria-related cardiovascular diseases such as heart failure.

pH-Triggered Transition from Micellar Aggregation to a Host-Guest Complex Accompanied by a Color Change.

A pH-triggered transition from micellar aggregation to a host-guest complex was achieved based on the supramolecular interactions between calixpyridinium and pyrroloquinoline quinone disodium salt (PQQ-2Na) accompanied by a color change. Our design has the following three advantages: (1) a regular spherical micellar assembly is fabricated by the supramolecular interactions between calixpyridinium and PQQ-2Na at pH 6 in an aqueous solution, (2) increasing the pH can lead to a transition from micellar aggregation to a host-guest complex due to the deprotonation of calixpyridinium, and at the same time (3) increasing the pH can lead to a color change owing to the deprotonation of calixpyridinium and the complexation of deprotonated calixpyridinium with PQQ-2Na. Benefitting from the low toxicity of calixpyridinium and PQQ-2Na, this pH-induced transition from micellar aggregation to a host-guest complex was further studied as a controllable-release model.

Topoisomerase IIIß Deficiency Induces Neuro-Behavioral Changes and Brain Connectivity Alterations in Mice.

Topoisomerase IIIß (Top3ß), the only dual-activity topoisomerase in mammals that can change topology of both DNA and RNA, is known to be associated with neurodevelopment and mental dysfunction in humans. However, there is no report showing clear associations of Top3ß with neuropsychiatric phenotypes in mice. Here, we investigated the effect of Top3ß on neuro-behavior using newly generated Top3ß deficient (Top3ß-/-) mice. We found that Top3ß-/- mice showed decreased anxiety and depression-like behaviors. The lack of Top3ß was also associated with changes in circadian rhythm. In addition, a clear expression of Top3ß was demonstrated in the central nervous system of mice. Positron emission tomography/computed tomography (PET/CT) analysis revealed significantly altered connectivity between many brain regions in Top3ß-/- mice, including the connectivity between the olfactory bulb and the cerebellum, the connectivity between the amygdala and the olfactory bulb, and the connectivity between the globus pallidus and the optic nerve. These connectivity alterations in brain regions are known to be linked to neurodevelopmental as well as psychiatric and behavioral disorders in humans. Therefore, we conclude that Top3ß is essential for normal brain function and behavior in mice and that Top3ß could be an interesting target to study neuropsychiatric disorders in humans.

Naa12 compensates for Naa10 in mice in the amino-terminal acetylation pathway.

Amino-terminal acetylation is catalyzed by a set of N-terminal acetyltransferases (NATs). The NatA complex (including X-linked Naa10 and Naa15) is the major acetyltransferase, with 40-50% of all mammalian proteins being potential substrates. However, the overall role of amino-terminal acetylation on a whole-organism level is poorly understood, particularly in mammals. Male mice lacking Naa10 show no globally apparent in vivo amino-terminal acetylation impairment and do not exhibit complete embryonic lethality. Rather Naa10 nulls display increased neonatal lethality, and the majority of surviving undersized mutants exhibit a combination of hydrocephaly, cardiac defects, homeotic anterior transformation, piebaldism, and urogenital anomalies. Naa12 is a previously unannotated Naa10-like paralog with NAT activity that genetically compensates for Naa10. Mice deficient for Naa12 have no apparent phenotype, whereas mice deficient for Naa10 and Naa12 display embryonic lethality. The discovery of Naa12 adds to the currently known machinery involved in amino-terminal acetylation in mice.

Anti-Inflammatory Actions of Soluble Ninjurin-1 Ameliorate Atherosclerosis.

BACKGROUND: Macrophages produce many inflammation-associated molecules, released by matrix metalloproteinases, such as adhesion molecules, and cytokines, as well, which play a crucial role in atherosclerosis. In this context, we investigated the relationship between Ninjurin-1 (Ninj1 [nerve injury-induced protein]), a novel matrix metalloproteinase 9 substrate, expression, and atherosclerosis progression. METHODS: Ninj1 expression and atherosclerosis progression were assessed in atherosclerotic aortic tissue and serum samples from patients with coronary artery disease and healthy controls, and atheroprone apolipoprotein e-deficient (Apoe-/-) and wild-type mice, as well. Apoe-/- mice lacking systemic Ninj1 expression (Ninj1-/-Apoe-/-) were generated to assess the functional effects of Ninj1. Bone marrow transplantation was also used to generate low-density lipoprotein receptor-deficient (Ldlr-/-) mice that lack Ninj1 specifically in bone marrow-derived cells. Mice were fed a Western diet for 5 to 23 weeks, and atherosclerotic lesions were investigated. The anti-inflammatory role of Ninj1 was verified by treating macrophages and mice with the peptides Ninj11-56 (ML56) and Ninj126-37 (PN12), which mimic the soluble form of Ninj1 (sNinj1). RESULTS: Our in vivo results conclusively showed a correlation between Ninj1 expression in aortic macrophages and the extent of human and mouse atherosclerotic lesions. Ninj1-deficient macrophages promoted proinflammatory gene expression by activating mitogen-activated protein kinase and inhibiting the phosphoinositide 3-kinase/Akt signaling pathway. Whole-body and bone marrow-specific Ninj1 deficiencies significantly increased monocyte recruitment and macrophage accumulation in atherosclerotic lesions through elevated macrophage-mediated inflammation. Macrophage Ninj1 was directly cleaved by matrix metalloproteinase 9 to generate a soluble form that exhibited antiatherosclerotic effects, as assessed in vitro and in vivo. Treatment with the sNinj1-mimetic peptides, ML56 and PN12, reduced proinflammatory gene expression in human and mouse classically activated macrophages, thereby attenuating monocyte transendothelial migration. Moreover, continuous administration of mPN12 alleviated atherosclerosis by inhibiting the enhanced monocyte recruitment and inflammation characteristics of this disorder in mice, regardless of the presence of Ninj1. CONCLUSIONS: Ninj1 is a novel matrix metalloproteinase 9 substrate in macrophages, and sNinj1 is a secreted atheroprotective protein that regulates macrophage inflammation and monocyte recruitment in atherosclerosis. Moreover, sNinj1-mediated anti-inflammatory effects are conserved in human macrophages and likely contribute to human atherosclerosis.

UV Accelerated Assemblies Constructed Using Calixpyridinium in Aqueous Solution.

In this work, an irregular calixpyridinium-suramin sodium supramolecular assembly was constructed by the strong host-guest electrostatic interactions. More interestingly, a novel regular spherical supramolecular assembly was also fabricated by the hydrogen bonding interactions between suramin sodium and the UV accelerated addition product of deprotonated calixpyridinium in water. The same principle was also applied to construct a UV accelerated regular spherical self-assembly by the addition product of deprotonated calixpyridinium in water. Compared with the complicated and irreversible covalent connection of the light-responsive groups to the building block, which is one of the common means of obtaining light-responsive supramolecular systems, this finding not only provides a smart, facile, and universally applicable method to construct deprotonated calixpyridinium-based light-responsive host-guest systems but also provides a new idea for the development of other novel light-responsive building blocks.

CD137 Signaling Regulates Acute Colitis via RALDH2-Expressing CD11b-CD103+ DCs.

CD137, a potent costimulatory receptor for CD8+ T cells, is expressed in various non-T cells, but little is known about its regulatory functions in these cells. In this study, we show that CD137 signaling, specifically in intestinal CD11b-CD103+ dendritic cells (DCs), restricts acute colitis progression. Mechanistically, CD137 engagement activates TAK1 and subsequently stimulates the AMPK-PGC-1α axis to enhance expression of the Aldh1a2 gene encoding the retinoic acid (RA) metabolizing enzyme RALDH2. RA can act on CD11b+CD103- DCs and induce SOCS3 expression, which, in turn, suppresses p38MAPK activation and interleukin-23 (IL-23) production. Administration of RA in DC-specific CD137-/- mice represses IL-23-producing CD11b+CD103- DCs and TH17 cells, indicating that RA is a major inhibitory effector molecule against intestinal CD11b+CD103- DCs. Additionally, the therapeutic effect of the anti-CD137 antibody is abrogated in DC-specific CD137-/- mice. Taken together, our results define a mechanism of paracrine immunoregulation operating between adjacent DC subsets in the intestine.

Characterization of human cardiac mesenchymal stromal cells and their extracellular vesicles comparing with human bone marrow derived mesenchymal stem cells.

Cardiac regeneration with adult stem-cell (ASC) therapy is a promising field to address advanced cardiovascular diseases. In addition, extracellular vesicles (EVs) from ASCs have been implicated in acting as paracrine factors to improve cardiac functions in ASC therapy. In our work, we isolated human cardiac mesenchymal stromal cells (h-CMSCs) by means of three-dimensional organ culture (3D culture) during ex vivo expansion of cardiac tissue, to compare the functional efficacy with human bone-marrow derived mesenchymal stem cells (h-BM-MSCs), one of the actively studied ASCs. We characterized the h-CMSCs as CD90low, c-kitnegative, CD105positive phenotype and these cells express NANOG, SOX2, and GATA4. To identify the more effective type of EVs for angiogenesis among the different sources of ASCs, we isolated EVs which were derived from CMSCs with either normoxic or hypoxic condition and BM-MSCs. Our in vitro tube-formation results demonstrated that the angiogenic effects of EVs from hypoxia-treated CMSCs (CMSC-Hpx EVs) were greater than the well-known effects of EVs from BM-MSCs (BM-MSC EVs), and these were even comparable to human vascular endothelial growth factor (hVEGF), a potent angiogenic factor. Therefore, we present here that CD90lowc-kitnegativeCD105positive CMSCs under hypoxic conditions secrete functionally superior EVs for in vitro angiogenesis. Our findings will allow more insights on understanding myocardial repair. [BMB Reports 2020; 53(2): 118-123].

Supramolecular Amphiphilic Assembly Formed by the Complexation of Calixpyridinium with Alimta.

In this work, the host-guest interaction between calixpyridinium and anionic anticancer drug Alimta was studied in aqueous media. Spherical supramolecular amphiphilic assembly rather than simple complex was accidentally fabricated by the complexation of calixpyridinium with Alimta. It is the third kind of anionic guest to be discovered to form the higher-order assembly by the complexation of calixpyridinium besides polyanionic guest and anionic gemini surfactant guest. The finding of this assembly approach supplies a new idea to construct various self-assembly architectures in water via the complexation of calixpyridinium with anionic drugs. The resulting calixpyridinium-drug assemblies may also have the potential to adjust the effects of drugs.

N-α-acetyltransferase 10 (NAA10) in development: the role of NAA10.

N-α-acetyltransferase 10 (NAA10) is a subunit of Nα-terminal protein acetyltransferase that plays a role in many biological processes. Among the six N-α-acetyltransferases (NATs) in eukaryotes, the biological significance of the N-terminal acetyl-activity of Naa10 has been the most studied. Recent findings in a few species, including humans, indicate that loss of N-terminal acetylation by NAA10 is associated with developmental defects. However, very little is known about the role of NAA10, and more research is required in relation to the developmental process. This review summarizes recent studies to understand the function of NAA10 in the development of multicellular organisms.

Prdx1 (peroxiredoxin 1) deficiency reduces cholesterol efflux via impaired macrophage lipophagic flux.

Oxidative stress activates macroautophagy/autophagy and contributes to atherogenesis via lipophagic flux, a form of lipid removal by autophagy. However, it is not known exactly how endogenous antioxidant enzymes are involved in lipophagic flux. Here, we demonstrate that the antioxidant PRDX1 (peroxiredoxin 1) has a crucial role in the maintenance of lipophagic flux in macrophages. PRDX1 is more highly expressed than other antioxidant enzymes in monocytes and macrophages. We determined that Prdx1 deficiency induced excessive oxidative stress and impaired maintenance of autophagic flux in macrophages. Prdx1-deficient macrophages had higher intracellular cholesterol mass and lower cholesterol efflux compared with wild type. This perturbation in cholesterol homeostasis was due to impaired lipophagic cholesterol hydrolysis caused by excessive oxidative stress, resulting in the inhibition of free cholesterol formation and the reduction of NR1H3 (nuclear receptor subfamily 1, group H, member 3) activity. Notably, impairment of both lipophagic flux and cholesterol efflux was restored by the 2-Cys PRDX-mimics ebselen and gliotoxin. Consistent with this observation, apoe -/- mice transplanted with bone marrow from prdx1-/-apoe-/- mice had increased plaque formation compared with apoe-/- BM-transplanted recipients. This study reveals that PRDX1 is crucial to regulating lipophagic flux and maintaining macrophage cholesterol homeostasis against oxidative stress. We suggest that PRDX1-dependent control of oxidative stress may provide a strategy for treating atherosclerosis and autophagy-related human diseases.

The Role of Macrophage Lipophagy in Reverse Cholesterol Transport

Macrophage cholesterol efflux is a central step in reverse cholesterol transport, which helps to maintain cholesterol homeostasis and to reduce atherosclerosis. Lipophagy has recently been identified as a new step in cholesterol ester hydrolysis that regulates cholesterol efflux, since it mobilizes cholesterol from lipid droplets of macrophages via autophagy and lysosomes. In this review, we briefly discuss recent advances regarding the mechanisms of the cholesterol efflux pathway in macrophage foam cells, and present lipophagy as a therapeutic target in the treatment of atherosclerosis.

ARD1-mediated Hsp70 acetylation balances stress-induced protein refolding and degradation.

Heat shock protein (Hsp)70 is a molecular chaperone that maintains protein homoeostasis during cellular stress through two opposing mechanisms: protein refolding and degradation. However, the mechanisms by which Hsp70 balances these opposing functions under stress conditions remain unknown. Here, we demonstrate that Hsp70 preferentially facilitates protein refolding after stress, gradually switching to protein degradation via a mechanism dependent on ARD1-mediated Hsp70 acetylation. During the early stress response, Hsp70 is immediately acetylated by ARD1 at K77, and the acetylated Hsp70 binds to the co-chaperone Hop to allow protein refolding. Thereafter, Hsp70 is deacetylated and binds to the ubiquitin ligase protein CHIP to complete protein degradation during later stages. This switch is required for the maintenance of protein homoeostasis and ultimately rescues cells from stress-induced cell death in vitro and in vivo. Therefore, ARD1-mediated Hsp70 acetylation is a regulatory mechanism that temporally balances protein refolding/degradation in response to stress.

Chemical Components from the Stems of Pueraria lobata and Their Tyrosinase Inhibitory Activity

Phytochemical investigation of the stems of Pueraria lobata (Wild) Ohwi (Leguminosae), led to the isolation of eighteen known compounds: β-amyrone (1), (+)-pinoresinol (2), (+)-syringaresinol (3) (+)-syringaresinol-O-β-D-glucoside (4), (+)-lariciresinol (5), (-)-tuberosin (6), naringenin (7), liquiritigenin (8), isoliquiritigenin (9) genistein (10), daidzein (11) daidzin (12) daidzein 4',7-diglucoside (13) 2,4,4'-trihydroxy deoxybenzoin (14), S-(+)-1-hydroxy-3-(4-hydroxyphenyl)-1-(4-hydroxy-2-methoxy-phenyl)propan-2-one (15), methyl 2-O-β-D-glucopyranosylbenzoate (16), pyromeconic acid 3-O-β-D-glucopyranoside 6'-(O-4''-hydroxy-3-methoxybenzoate) (17), and allantion (18). The chemical structures of these compounds were elucidated from spectroscopic data and by comparison of those data with previously published results. The effects of isolated compounds on mushroom tyrosinase enzymatic activity were screened. The results indicated that, chloroform extract of P. lobata stems turned out to be having tyrosinase inhibitory effect, and only compounds 5, 8, 9, and 11 showed enzyme inhibitory activity, with IC₅₀ values of 21.49 ± 4.44, 25.24 ± 6.79, 4.85 ± 2.29, and 17.50 ± 1.29 µM, respectively, in comparison with these of positive control, kojic acid (IC₅₀ 12.28 ± 2.72 µM). The results suggest that P. lobata stems extract as well as its chemical components may represent as potential candidates for tyrosinase inhibitors.

NAA10 controls osteoblast differentiation and bone formation as a feedback regulator of Runx2.

Runt-related transcription factor 2 (Runx2) transactivates many genes required for osteoblast differentiation. The role of N-α-acetyltransferase 10 (NAA10, arrest-defective-1), originally identified in yeast, remains poorly understood in mammals. Here we report a new NAA10 function in Runx2-mediated osteogenesis. Runx2 stabilizes NAA10 in osteoblasts during BMP-2-induced differentiation, and NAA10 in turn controls this differentiation by inhibiting Runx2. NAA10 delays bone healing in a rat calvarial defect model and bone development in neonatal mice. Mechanistically, NAA10 acetylates Runx2 at Lys225, and this acetylation inhibits Runx2-driven transcription by interfering with CBFß binding to Runx2. Our study suggests that NAA10 acts as a guard ensuring balanced osteogenesis by fine-tuning Runx2 signalling in a feedback manner. NAA10 inhibition could be considered a potential strategy for facilitating bone formation.

The adipokine Retnla modulates cholesterol homeostasis in hyperlipidemic mice.

Hyperlipidemia is a well-recognized risk factor for atherosclerosis and can be regulated by adipokines. Expression of the adipokine resistin-like molecule alpha (Retnla) is regulated by food intake; whether Retnla has a role in the pathogenesis of hyperlipidemia and atherosclerosis is unknown. Here we report that Retnla has a cholesterol-lowering effect and protects against atherosclerosis in low-density lipoprotein receptor-deficient mice. On a high-fat diet, Retnla deficiency promotes hypercholesterolaemia and atherosclerosis, whereas Retnla overexpression reverses these effects and improves the serum lipoprotein profile, with decreased cholesterol in the very low-density lipoprotein fraction concomitant with reduced serum apolipoprotein B levels. We show that Retnla upregulates cholesterol-7-α-hydroxylase, a key hepatic enzyme in the cholesterol catabolic pathway, through induction of its transcriptional activator liver receptor homologue-1, leading to increased excretion of cholesterol in the form of bile acids. These findings define Retnla as a novel therapeutic target for treating hypercholesterolaemia and atherosclerosis.

Developmental endothelial locus-1 inhibits MIF production through suppression of NF-κB in macrophages.

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that regulates leukocyte recruitment, thereby playing a pivotal role in the regulation of innate and adaptive immunity and tumor progression. Elevated levels of MIF are associated with numerous inflammatory disorders and cancers. To determine whether developmental endothelial locus-1 (Del-1) regulated MIF, RAW264.7 macrophages were treated with Del-1 and assessed using ELISA. The results showed that MIF was downregulated in macrophages by Del-1, an endogenous anti-inflammatory protein that was previously shown to limit leukocyte adhesion and migration. Treatment of RAW264.7 macrophages with Del-1 inhibited constitutive and lipopolysaccharide (LPS)-induced MIF secretion. Recombinant Del-1 protein attenuated the phosphorylation of IκBα induced by a relatively low concentration of LPS in THP-1 monocytes, but did not inhibit IκBα phosphorylation in response to a relatively high concentration of LPS. Concomitantly, translocation of NF-κB to the nucleus was inhibited by Del-1 in LPS-activated macrophages. In addition, conditioned medium harvested from cells transfected with a Del-1 expression plasmid suppressed NF-κB activation in response to relatively low concentrations of TNF-α, albeit not the activation that was induced by a relatively high concentration of TNF-α. On the other hand, although Del-1 enhanced the macrophage expression of p53, a known negative regulator of MIF production, MIF production was not significantly affected by the level of p53 in mouse bone marrow-derived macrophages. These findings suggested that Del-1 controls NF-κB-activated MIF production in macrophages, and the potential application of Del-1 to therapeutic modalities for chronic inflammation-associated cancers.

Ninjurin1 deficiency attenuates susceptibility of experimental autoimmune encephalomyelitis in mice.

Ninjurin1 is a homotypic adhesion molecule that contributes to leukocyte trafficking in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. However, in vivo gene deficiency animal studies have not yet been done. Here, we constructed Ninjurin1 knock-out (KO) mice and investigated the role of Ninjurin1 on leukocyte trafficking under inflammation conditions such as EAE and endotoxin-induced uveitis. Ninjurin1 KO mice attenuated EAE susceptibility by reducing leukocyte recruitment into the injury regions of the spinal cord and showed less adhesion of leukocytes on inflamed retinal vessels in endotoxin-induced uveitis mice. Moreover, the administration of a custom-made antibody (Ab26-37) targeting the Ninjurin1 binding domain ameliorated the EAE symptoms, showing the contribution of its adhesion activity to leukocyte trafficking. In addition, we addressed the transendothelial migration (TEM) activity of bone marrow-derived macrophages and Raw264.7 cells according to the expression level of Ninjurin1. TEM activity was decreased in Ninjurin1 KO bone marrow-derived macrophages and siNinj1 Raw264.7 cells. Consistent with this, GFP-tagged mNinj1-overexpressing Raw264.7 cells increased their TEM activity. Taken together, we have clarified the contribution of Ninjurin1 to leukocyte trafficking in vivo and delineated its direct functions to TEM, emphasizing Ninjurin1 as a beneficial therapeutic target against inflammatory diseases such as multiple sclerosis.

p53 regulates the transcription of the anti-inflammatory molecule developmental endothelial locus-1 (Del-1).

Developmental endothelial locus-1 (Del-1) is an endothelium-derived anti-inflammatory molecule that is downregulated by inflammatory stimuli. Little is known about the molecular mechanisms by which Del-1 transcription is regulated. In the present study, a DNA sequence upstream of the Del-1 gene was analyzed and putative p53 response elements (p53REs) were identified. An approximately 2 kb fragment upstream of the translation start site displayed the highest Del-1 transcriptional activity, and the transcriptional activity of this fragment was enhanced by overexpression of p53. Chemical activation of endogenous p53 elevated the levels of Del-1 mRNA. Site-directed mutagenesis of CATG in the consensus sequences of the 2 kb fragment to TATA significantly reduced the transcription of Del-1. Chromatin immunoprecipitation revealed recruitment of p53 to the p53REs of the Del-1 promoter, resulting in increased Del-1 transcription. Finally, primary endothelial cells isolated from mice with reduced levels of p53 showed a decrease in Del-1 mRNA compared to wild-type endothelial cells. Moreover, Del-1 reciprocally enhanced p53 expression in primary endothelial cells. Thus, these findings suggest that Del-1 is a novel transcriptional target gene of p53.