Lipid storage myopathy （LSM） is a lipid metabolic disorder characterized by excessive lipid droplet accumulation in muscle fibers. Classic multiple Acyl-CoA dehydrogenase deficiency （MADD）， also known as glutaric aciduria type Ⅱ， is a disease with various clinical manifestations caused by mutations in electron transfer flavoprotein （ETF） and ETF-ubiquinone oxidoreductase. In recent years， a large amount of evidence has shown that classic late-onset MADD caused by mutations in the electron transfer flavoprotein dehydrogenase gene is the main cause of LSM. Besides classic MADD， many other diseases with similar changes in blood acylcarnitines and urinary organic acids can also cause LSM， and such diseases are call MADD-like disorders or MADD spectrum. This article reviews the clinical， pathological， biochemical， and molecular features of LSM with various etiologies and the latest advances in treatment， with a focus on the latest findings associated with MADD spectrum.
Riboflavin

NAD(P)H: quinone oxidoreductase 1 (NQO1) is a flavin protease highly expressed in various cancer cells. NQO1 catalyzes a futile redox cycle in substrates, leading to substantial reactive oxygen species (ROS) production. This ROS generation results in extensive DNA damage and elevated poly (ADP-ribose) polymerase 1 (PARP1)-mediated consumption of nicotinamide adenine dinucleotide (NAD⁺), ultimately causing cell death. Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD⁺ salvage synthesis pathway, emerges as a critical target in cancer therapy. The concurrent inhibition of NQO1 and NAMPT triggers hyperactivation of PARP1 and intensive NAD⁺ depletion. In this study, we designed, synthesized, and assessed a novel series of proqodine A derivatives targeting both NQO1 and NAMPT. Among these, compound T8 demonstrated potent antitumor properties. Specifically, T8 selectively inhibited the proliferation of MCF-7 cells and induced apoptosis through mechanisms dependent on both NQO1 and NAMPT. This discovery offers a promising new molecular entity for advancing anticancer research.
Humans ; NAD/metabolism* ; Cell Line, Tumor ; Reactive Oxygen Species/metabolism* ; Nicotinamide Phosphoribosyltransferase/metabolism* ; Cytokines/metabolism* ; Quinones ; Oxidoreductases

Nicotinamide adenine dinucleotide（NADH） in its reduced form of is a key coenzyme in redox reactions, essential for maintaining energy homeostasis.NADH and its oxidized counterpart, NAD+, form a redox couple that regulates various biological processes, including calcium homeostasis, synaptic plasticity, anti-apoptosis, and gene expression. The reduction of NAD+/NADH levels is closely linked to mitochondrial dysfunction, which plays a pivotal role in the cascade of various neurodegenerative disorders, including Parkinson's disease and Alzheimer's disease.Auditory neuropathy（AN） is recognized as a clinical biomarker in neurodegenerative disorders. Furthermore, mitochondrial dysfunction has been identified in patients with mutations in genes like OPA1and AIFM1. However, effective treatments for these conditions are still lacking. Increasing evidence suggests that administratering NAD+ or its precursors endogenously may potentially prevent and slow disease progression by enhancing DNA repair and improving mitochondrial function. Therefore, this review concentrates on the metabolic pathways of NAD+/NADH production and their biological functions, and delves into the therapeutic potential and mechanisms of NADH in treating AN.
Humans ; NAD/metabolism* ; Neurodegenerative Diseases/metabolism* ; Mitochondria ; Oxidation-Reduction ; Mitochondrial Diseases

The synthesis of fine chemicals using multi-enzyme cascade reactions is a recent hot research topic in the field of biocatalysis. The traditional chemical synthesis methods were replaced by constructing in vitro multi-enzyme cascades, then the green synthesis of a variety of bifunctional chemicals can be achieved. This article summarizes the construction strategies of different types of multi-enzyme cascade reactions and their characteristics. In addition, the general methods for recruiting enzymes used in cascade reactions, as well as the regeneration of coenzyme such as NAD(P)H or ATP and their application in multi-enzyme cascade reactions are summarized. Finally, we illustrate the application of multi-enzyme cascades in the synthesis of six bifunctional chemicals, including ω-amino fatty acids, alkyl lactams, α, ω-dicarboxylic acids, α, ω-diamines, α, ω-diols, and ω-amino alcohols.
Amino Acids ; Biocatalysis ; Amino Alcohols ; Coenzymes/metabolism* ; Diamines

Nicotinamide mononucleotide (NMN) is one of the key precursors of coenzyme Ⅰ (NAD⁺). NMN exists widely in a variety of organisms, and β isomer is its active form. Studies have shown that β-NMN plays a key role in a variety of physiological and metabolic processes. As a potential active substance in anti-aging and improving degenerative and metabolic diseases, the application value of β-NMN has been deeply explored, and it is imminent to achieve large-scale production. Biosynthesis has become the preferred method to synthesize β-NMN because of its high stereoselectivity, mild reaction conditions, and fewer by-products. This paper reviews the physiological activity, chemical synthesis as well as biosynthesis of β-NMN, highlighting the metabolic pathways involved in biosynthesis. This review aims to explore the potential of improving the production strategy of β-NMN by using synthetic biology and provide a theoretical basis for the research of metabolic pathways as well as efficient production of β-NMN.
Nicotinamide Mononucleotide/metabolism* ; NAD/metabolism*

Auditory neuropathy spectrum disorder (ANSD) represents a variety of sensorineural deafness conditions characterized by abnormal inner hair cells and/or auditory nerve function, but with the preservation of outer hair cell function. ANSD represents up to 15% of individuals with hearing impairments. Through mutation screening, bioinformatic analysis and expression studies, we have previously identified several apoptosis-inducing factor (AIF) mitochondria-associated 1 (AIFM1) variants in ANSD families and in some other sporadic cases. Here, to elucidate the pathogenic mechanisms underlying each AIFM1 variant, we generated AIF-null cells using the clustered regularly interspersed short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system and constructed AIF-wild type (WT) and AIF-mutant (mut) (p.‍T260A, p.‍R422W, and p.‍R451Q) stable transfection cell lines. We then analyzed AIF structure, coenzyme-binding affinity, apoptosis, and other aspects. Results revealed that these variants resulted in impaired dimerization, compromising AIF function. The reduction reaction of AIF variants had proceeded slower than that of AIF-WT. The average levels of AIF dimerization in AIF variant cells were only 34.5%‍‒‍49.7% of that of AIF-WT cells, resulting in caspase-independent apoptosis. The average percentage of apoptotic cells in the variants was 12.3%‍‒‍17.9%, which was significantly higher than that (6.9%‍‒‍7.4%) in controls. However, nicotinamide adenine dinucleotide (NADH) treatment promoted the reduction of apoptosis by rescuing AIF dimerization in AIF variant cells. Our findings show that the impairment of AIF dimerization by AIFM1 variants causes apoptosis contributing to ANSD, and introduce NADH as a potential drug for ANSD treatment. Our results help elucidate the mechanisms of ANSD and may lead to the provision of novel therapies.
Humans ; Apoptosis Inducing Factor/metabolism* ; NAD/metabolism* ; Dimerization ; Apoptosis

OBJECTIVES: To explore the effect of acupuncture and moxibustion on intestinal flora in the rats with diarrhea-predominant irritable bowel syndrome (IBS-D) based on 16S rDNA technique. METHODS: Ten rats were randomized from 58 SPF-grade male SD rats to be the blank group. The remained 48 rats were prepared to be IBS-D models by the modified method of acetic acid enema combined with binding tail-clip stress. Forty successfully-modeled rats were randomly divided into a model group, an acupuncture group, a moxibustion group and a western medication group, with 10 rats in each one. In the acupuncture group, the needle was inserted at bilateral "Zusanli" (ST 36) and remained for 15 min in each rat. In the moxibustion group, the suspending moxibustion was delivered at bilateral "Zusanli" (ST 36) for 15 min. The rats in the western medication group were given pinaverium bromide suspension (10 mL/kg) by intragastric administration. The above interventions were performed once daily for consecutive 14 days. The body mass and the score of fecal trait were compared before and after modeling, as well as after intervention in each group. Fecal water content, diarrhea index and colon transit time (CTT) were measured after modeling and intervention in the rats of each group separately. After intervention, the colonic morphology of rats in each group was observed, and using 16S rDNA technique, the intestinal flora was detected. RESULTS: After modeling, compared with the blank group, the body mass and CTT were reduced (P<0.01); fecal trait scores, fecal water contents and diarrhea index increased (P<0.01) in the other 4 groups. After intervention, the body mass and CTT of the rats decreased (P<0.01), and fecal trait score, fecal water content and diarrhea index increased (P<0.01) in the model group compared with those in the blank group. In the acupuncture group, the moxibustion group and the western medication group, when compared with the model group, the body mass and CTT were elevated (P<0.01), while fecal trait scores, fecal water contents and diarrhea index declined (P<0.01). Compared with the western medication group, fecal water content decreased in the acupuncture group and the moxibustion group (P<0.05), while CTT increased in the acupuncture group (P<0.01), the body mass increased and fecal trait score was dropped in the moxibustion group (P<0.05). The colonic mucosa structure was clear and complete, and there was no obvious inflammatory cell infiltration in the blank group. The mild interstitial edema of intestinal mucosa was presented with the infiltration of few inflammatory cells in the model group. There was the infiltration of few inflammatory cells in the mucosa of the acupuncture group, the moxibustion group and the western medication group. Compared with the blank group, the indexes of Richness, Chao1, ACE and Shannon decreased in the model group (P<0.05). Indexes of Richness, Chao1 and ACE increased in the acupuncture group and the moxibustion group (P<0.05), and the Richness index in the western medication group increased (P<0.05) when compared with those in the model group. The relative abundance of Bacteroidetes, Proteobacteria and Prevotella increased (P<0.05), and that of Firmicutes and Muribaculaceae decreased (P<0.05) in the model group compared with those in the blank group. When compared with the model group, the relative abundance of Bacteroidetes, Proteobacteria and Prevotella was reduced (P<0.05), while that of Firmicutes and Muribaculaceae increased (P<0.05) in the acupuncture group, the moxibustion group and the western medication group; and that of Actinobacteria and Bifidobacterium increased in the acupuncture group and the moxibustion group (P<0.05). Compared with the blank group, the relative abundance of lipopolysaccharide (LPS) biosynthesis was elevated (P<0.05), and that of folate biosynthesis, lipoic acid metabolism, zeatin biosynthesis, ubiquinone and other terpenoid quinone biosynthesis decreased (P<0.05) in the model group. The relative abundance of LPS biosynthesis was dropped (P<0.05), and that of folate biosynthesis, lipoic acid metabolism, zeatin biosynthesis, ubiquinone and other terpenoid quinone biosynthesis increased (P<0.05) in the acupuncture group, the moxibustion group and the western medication group compared with those of the model group. CONCLUSIONS Either acupuncture or moxibustion can relieve the symptoms of IBS-D and protect intestinal mucosa, which may be associated with regulating the structure of intestinal flora and promoting nutrient metabolism and biosynthesis.
Rats ; Male ; Animals ; Irritable Bowel Syndrome/therapy* ; Moxibustion/methods* ; Rats, Sprague-Dawley ; Gastrointestinal Microbiome ; Lipopolysaccharides ; Thioctic Acid ; Ubiquinone ; Zeatin ; Acupuncture Therapy ; Diarrhea/therapy* ; Terpenes ; Water ; Folic Acid ; Acupuncture Points

Succinic acid is an important C4 platform chemical that is widely used in food, chemical, medicine sectors. The bottleneck of fermentative production of succinic acid by engineered Escherichia coli is the imbalance of intracellular cofactors, which often leads to accumulation of by-products, lower yield and low productivity. Stoichiometric analysis indicated that an efficient production of succinic acid by E. coli FMME-N-26 under micro-aeration conditions might be achieved when the TCA cycle provides enough ATP and NADH for the r-TCA pathway. In order to promote succinic acid production, a serial of metabolic engineering strategies include reducing ATP consumption, strengthening ATP synthesis, blocking NADH competitive pathway and constructing NADH complementary pathway were developed. As result, an engineered E. coli FW-17 capable of producing 139.52 g/L succinic acid and 1.40 g/L acetic acid in 5 L fermenter, which were 17.81% higher and 67.59% lower than that of the control strain, was developed. Further scale-up experiments were carried out in a 1 000 L fermenter, and the titer of succinic acid and acetic acid were 140.2 g/L and 1.38 g/L, respectively.
Escherichia coli/genetics* ; NAD ; Succinic Acid ; Acetic Acid ; Adenosine Triphosphate

This study aims to investigate the mechanism of Linderae Radix water extract(LRWE) in the prevention and treatment of diarrhea-predominant irritable bowel syndrome(IBS-D) based on serum metabolomics. Eighteen 2-week-old male SD rats were randomized into control, IBS-D model, and LRWE groups. The rats in other groups except the control group received gavage of senna concentrate combined with restraint stress for the modeling of IBS-D. The rats in the LRWE group were administrated with LRWE(5.4 g·kg~(-1)) by gavage, and those in the control and IBS-D model groups with an equal volume of distilled water for a total of 14 days. The visceral sensitivity was evaluated by the abdominal withdrawal reflex(AWR) score, and the degree of diarrhea was assessed by the fecal water content(FWC). The morphological changes of the colon and the morphology and number of goblet cells were observed by hematoxylin-eosin(HE) and periodic acid-schiff(PAS) staining, respectively. Ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) was used for the screening of the potential biomarkers in the rat serum and their related metabolic pathways. The results showed that LRWE reduced the AWR score, decreased FWC, and alleviated visceral sensitivity and diarrhea symptoms in IBS-D rats. HE and PAS staining showed that LRWE mitigated low-grade intestinal inflammation and increased the number of mature secretory goblet cells in the colonic epithelium of IBS-D rats. A total of 25 potential biomarkers of LRWE in treating IBS-D were screened out in this study, which were mainly involved in riboflavin, tryptophan, glycine, serine and threonine metabolism, glyoxylate and dicarboxylate metabolism, and cysteine and methionine metabolism. The regulatory effects were the most significant on the riboflavin and tryptophan metabolism pathways. LRWE may alleviate the visceral hypersensitivity by promoting energy metabolism and amino acid metabolism, enhancing intestinal barrier function, and improving intestinal immune function in IBS-D rats.
Rats ; Male ; Animals ; Irritable Bowel Syndrome/metabolism* ; Water ; Chromatography, Liquid ; Tryptophan ; Rats, Sprague-Dawley ; Tandem Mass Spectrometry ; Diarrhea/drug therapy* ; Biomarkers ; Riboflavin

Objective To compare the sensitivity and accuracy of amplified luminescent proximity homogeneous assay linked immunosorbent assay (AlphaLISA) and magnetic particles-based chemiluminescence immunoassay (MP-CLIA) for detection of staphylococcal enterotoxin C (SEC) in the simulated milk samples. Methods The AlphaLISA was constructed using goat anti-SEC polyclonal antibody-coupled receptor microspheres, biotin-labeled SEC monoclonal antibody and streptavidin-coupled donor microspheres. The MP-CLIA was constructed using goat anti-SEC polyclonal antibody conjugated alkaline phosphatase, biotin-labeled anti-SEC monoclonal antibody and streptavidin conjugated magnetic beads. Results The sensitivity of AlphaLISA to detect SEC content in simulated milk samples was 4.04 ng/L, and the coefficient of variation (CV) was 1.98%~9.82%. The sensitivity of MP-CLIA was 108.19 ng/L and CV was 4.63%~20.40%. Conclusion Compared with MP-CLIA, AlphaLISA is more sensitive and accurate to detecting SEC.
Animals ; Streptavidin ; Biotin ; Luminescence ; Milk ; Antibodies, Monoclonal ; Goats ; Immunoassay/methods*