Project description:Cancer immunotherapy has reshaped the landscape of cancer treatment, but its effectiveness is limited by tumor immunosuppression caused by excessive lactate production by cancer cells. While efforts to reduce lactate levels through lactate dehydrogenase inhibition have been made, such inhibitors can disrupt the metabolism of healthy cells and cause severe non-specific toxicity. Based on lactate oxidase, we report herein an enzyme therapeutic, which reduces lactate levels, releases an immunostimulatory molecule-hydrogen peroxide, averts tumor immunosuppression, and synergistically improves the efficacy of immune checkpoint blockades, as demonstrated in a murine melanoma model and a humanized mouse model of triple-negative breast cancer.
Project description:Histone acetylation involves the transfer of a two-carbon unit to nucleus as embedded in low-concentration metabolites. We find that lactate, a high-concentration metabolic by-product, can be a major carbon source for histone acetylation, through oxidation-dependent metabolism. Both in cells and in purified nucleus, 13C3-lactate carbons are incorporated into histone H4 (maximum incorporation: ~60%). In purified nucleus, this process depends on nucleus-localized lactate dehydrogenase (LDHA), the knockout of which abrogates the incorporation. Heterologous expression of nucleus-localized LDHA rescues the KO effect. Lactate itself increases histone acetylation, whereas inhibition of LDHA reduces the acetylation. In vitro and in vivo settings exhibit different lactate incorporation patterns, suggesting an influence of the microenvironment. Higher nuclear LDHA localization is observed in pancreatic cancer than in normal tissues, showing the disease relevance. Overall, lactate and nuclear LDHA can be major structural and regulatory players in the metabolism-epigenetics axis controlled by cell’s own or environmental status.
Project description:We found that lactate and lactylation were significantly elevated in rotator cuff tears, and lactylation primarily regulates histones in tenocytes. Therefore, we screened for histone lactylation and identified that H3K9, H4K8, and H4K16 had the most prominent increases. Subsequently, we conducted CUT - Tag assays on them. The results indicated that H3K9la was enriched at the promoters of ENO3 and COL1, while H4K16la was enriched at the promoter of TNMD, which induced the transcriptional expression of these genes. Moreover, as a glycolytic enzyme, ENO3 is further involved in the H3K9la–Eno3–lactate–H3K9la positive feedback loop to maintain a high lactate level. This feedback loop continuously drives the H3K9 - COL1 and H4K16 - TNMD regulatory axes, ultimately promoting the repair of rotator cuff tear injuries.
Project description:Lactate is abundant in the tumor environment as the secreted product of fermentative cells. In prostate cancer (PCa), cancer-associated fibroblasts are the major contributors and this secreted lactate is uptaken by cancer cells to sustain their mitochondrial metabolism. However, how lactate controls the metabolic and transcriptional regulation in tumors is far to be elucidated. Here, we identify an innovative lactate-driven mechanism able to increase the expression of genes involved in lipid metabolism in PCa cells. This regulation enhances intracellular lipid accumulation in lipid droplets (LDs) and provides acetyl moieties for histone acetylation, establishing a regulatory loop between metabolites and epigenetic control. Interestingly, inhibition of this loop by targeting bromodomains histone acetylation readers suppresses the expression of perilipin-2 (PLIN2), a crucial component of LDs, disrupting the lactate-dependent lipid metabolic rewiring. Since this metabolic-epigenetic regulatory loop sustains PCa metastatic potential, its targeting is of clinical relevance as demonstrated by the inhibition of PCa invasive potential in vivo. Overall, our findings show that lactate has both a metabolic and an epigenetic role in promoting PCa progression.
Project description:Corynebacterium glutamicum is able to grow with lactate as sole or combined carbon and energy source. Quinone-dependent L-lactate dehydrogenase LldD is known to be essential for utilization of L-lactate by C. glutamicum. D-lactate also serves as sole carbon source for C. glutamicum ATCC 13032. Here, the gene cg1027 was shown to encode the quinone-dependent D-lactate dehydrogenase (Dld) by enzymatic analysis of the protein purified from recombinant E. coli. The absorption spectrum of purified Dld indicated the presence of FAD as bound cofactor. Inactivation of dld resulted in the loss of the ability to grow with D-lactate, which could be restored by plasmid-borne expression of dld. Heterologous expression of dld from C. glutamicum ATCC 13032 in C. efficiens enabled this species to grow with D-lactate as sole carbon source. Homologs of dld of C. glutamicum ATCC 13032 are not encoded in the sequenced genomes of other corynebacteria and mycobacteria. However, the dld locus of C. glutamicum ATCC 13032 shares 2367 bp of 2372 bp identical nucleotides with the dld locus of Propionibacterium freudenreichii subsp. shermanii, a bacterium used in Swiss-type cheese making. Both loci are flanked by insertion sequences of the same family suggesting a possible event of horizontal gene transfer.
Project description:Eubacterium limosum is a dominant member of the human gut microbiome and produces short-chain fatty acids (SCFAs). These promote immune system function and inhibit inflammation, making this microbe important for human health. Lactate is a primary source of gut SCFAs but its utilization by E. limosum has not been explored. We show that E. limosum growing on lactate takes up added tungstate rather than molybdate and produces the SCFAs acetate and butyrate, but not propionate. The genes encoding an electron bifurcating, tungsten-containing oxidoreductase (WOR1) and a tungsten-containing formate dehydrogenase (FDH), along with an electron bifurcating lactate dehydrogenase (LCT), lactate permease and enzymes of the propanediol pathway, are all up-regulated on lactate compared to growth on glucose. Lactate metabolism is controlled by a GntR-family repressor (LctR) and two global regulators, Rex and CcpA, where Rex in part controls W storage and tungstopyranopterin (Tuco) biosynthesis. Tuco-dependent riboswitches, along with CcpA, also control two iron transporters, consistent with the increased iron demand for many iron-containing enzymes, including WOR1 and FDH, involved in SCFA production. From intracellular aldehyde concentrations and the substrate specificity of WOR1, we propose that WOR1 is involved in detoxifying acetaldehyde produced during lactate degradation. Lactate to SCFA conversion by E. limosum is clearly highly tungstocentric and tungsten might be an overlooked micronutrient in the human microbiome and in overall human health.
Project description:Microglial activation is a central pathological hallmark of Parkinson's disease (PD). Microglia switch metabolism from oxidative phosphorylation (OXPHOS) toward glycolysis upon pro-inflammatory activation. Glycolysis-drived lactylate accumulation contributed to the development and progression of PD. However, the underlying mechanisms remain unclear. Here, after first detecting elevated lactate in PD mice, we also observed that up-regulated lactylation was accompanied by increased microglia activation. Furthermore, endogenous lactate-derived lactylation was ultimately involved in the pathological process of PD. Next, the global lactylome revealed that dihydrolipoyl dehydrogenase (Dld) at Lys 127, 277, 410 site were elevated. Further functional verification studies showed that hyperlactylation of Dld at Lys 127 inhibited pyruvate dehydrogenase (PDH) enzyme activity and promoted the metabolism of lactate-pyruvate transition, ultimately alleviating dopamine (DA) neuronal damage. Meanwhile, p300 (lactylation writer) was increased in PD mice and pharmacologic inhibition of p300 could attenuate PD. Together, this work demonstrated a lactate/Dld-K127/pyruvate positive feedback loop that drived DA neuronal damage in “metabolism - epigenetic” level and suggested that suppressing this vicious feedback circle as a promising therapeutic target for PD.
Project description:Protein lactylation is a process that is fueled by lactate, generated by the enzyme lactate dehydrogenase (Ldh) from pyruvate. Despite prior research, the precise role of protein lactylation in controlling the identity of mouse embryonic stem cells (ESCs) is still not fully understood. We observed that inhibiting or eliminating Ldha causes a reduction in global protein lactylation in ESCs, and RNA-seq analysis suggests that Ldha inhibition induces a 2-cell-like cell (2CLC) signature in ESCs. To probe the underlying mechanisms, we performed quantitative lactylation proteomics analysis, we discovered that Hdac1, a gene with significant regulatory roles during the 2-cell stage (2C), undergoes lactylation modification. Additionally, we observed that treatment with an Ldh (lactate dehydrogenase) inhibitor can decrease the lactylation levels of Hdac1. Mechanistically, we discovered that Ldha positively regulates the lactylation of Hdac1, promoting its direct binding to zygotic genome activation (ZGA) gene promoters and has stronger deacetylase activity. This leads to the removal of acetyl groups from H3K27 on these loci, effectively suppressing the expression of 2C genes. Our study presents novel evidence supporting protein lactylation's potential as a means of inhibiting the generation of 2CLCs and modulating acetylation activity.
Project description:Previous findings have demonstrated that the NADH/NAD+ ratio has a strong impact on the glycolytic flux in C. glutamicum under anaerobic conditions in the absence of external electron acceptors. During an attempt to rewire anaerobic metabolism to achieve high yield formation of ethanol, we inactivated the malate dehydrogenase and lactate dehydrogenase in a C. glutamicum strain expressing pyruvate decarboxylase and alcohol dehydrogenase, to eliminate formation of the by-products succinate and lactate, respectively. This modification increased the yield of ethanol but had a negative effect on glycolysis, which we found to correlate with an elevated NADH/NAD+ ratio. The pyruvate dehydrogenase (PDH) of C. glutamicum is active under anaerobic conditions, and can potentially exacerbate the negative effect on glycolysis, due to NADH formation. To reduce PDH activity under anaerobic conditions, we decided to replace the gene encoding the E3 subunit of PDH with its Escherichia coli counterpart, as E. coli PDH has been reported to be functional under aerobic conditions only. The resultant strain JS133 produced far less acetate with a further increased ethanol production, however, the glycolytic flux was still low. After observing differences in glycolytic flux for JS133 on glucose and fructose, we speculated that the pentose phosphate pathway (PPP) might be involved in the reduced flux on glucose. To prove this, we deleted the zwf gene, encoding glucose-6-phosphate dehydrogenase, which is the entry point into PPP, and immediately observed a stimulating effect on glycolysis. Subsequent characterization revealed a direct correlation between the intracellular NADH/NAD+ and NADPH/NADP+ ratios under anoxic conditions. Based on these findings we managed to re-channel the metabolism of C. glutamicum successfully towards either to ethanol or D-lactate with 92% and 98% of the theoretical yield respectively, which is the highest yields for D-lactate production thus far reported in the literature.