Controls of uranyl species and metabolism on Bacillus subtilis-enhanced uranium bio-immobilization.

Ectophosphatase activities and phosphate transport mechanisms in Tritrichomonas foetus and their impact on parasite proliferation.

Fungi deploy host phosphate signaling disrupter.

An 85-year-old woman with diffuse large B-cell lymphoma developed severe hypophosphatemia (serum phosphate 0.3 mg/dL) concomitant with acute kidney injury (serum creatinine 2.05 mg/dL) following chemotherapy. Because urine phosphate was undetectable, hypophosphatemia was likely due to the vigorous uptake of phosphate into the rapidly proliferating tumor cells, also known as tumor genesis syndrome (TGS), and acute kidney injury was potentially attributed to the antibiotics sulfamethoxazole/trimethoprim. Oral phosphate supplementation and antibiotic discontinuation alleviated both the abnormalities. This case was unusual, as tumorigenesis syndrome is seldom seen in patients with lymphoma, and acute kidney injury usually leads to hyperphosphatemia. The present case emphasizes the importance of vigilance in hypophosphatemia due to TGS during chemotherapy.

Imbalance of phosphoric acid homeostasis in alveolar macrophages mediates lung toxicity of rare earth oxide nanoparticles.

Lysine acetylation has been shown to be an abundant and vital post-translational modification (PTM) that utilizes acetyl phosphate (AcP) as one of the acetyl group donors in bacteria. The pyruvate dehydrogenase (PDH) complex catalyzes the conversion from pyruvate to acetyl coenzyme A (acetyl-CoA). Thus far, the connection between lysine acetylation and pyruvate metabolism has not been thoroughly investigated. In this study, we show that AcP could acetylateEscherichia coli pyruvate dehydrogenase (AceE)in vitro andin vivo, which could be reversed by protein lysine deacetylase (CobB).In vitro treatment of AceE with AcP also causes increased phosphorylation of the protein, whereas deletingackA does not affect the phosphorylation of the protein. As a result,in vitro treatment of AceE by AcP leads to decreased enzymatic activity. In contrast, deletingackA leads to increased acetylation and enzymatic activity of AceE, and deletingpta results in the decreased acetylation and enzymatic activity of AceE. As expected, deletingpta inE.coli causes pyruvate accumulation. Although deletingackA also causes pyruvate accumulation, decreased expression of the two genes involved in pyruvate metabolism (ldhA andpoxB) is observed in the mutant, indicating that AcP could affect pyruvate metabolism by other routes in addition to modulating the AceE activity. Thus, our results demonstrate that intracellular AcP could modulate pyruvate metabolism inE.coli. For the first time, a linkage between AcP-mediated protein lysine acetylation, pyruvate dehydrogenase activity, and pyruvate metabolism is established.

Abstract SLC34A2 is overexpressed in 61% of ovarian cancer and 18% of uterine cancer tumors. SLC34A2 overexpression is believed to be driven by the aberrant activity of the essential PAX8 transcription factor in these tumors. Overexpression of SLC34A2, a phosphate importer, sensitizes the cells to the genetic depletion of XPR1, the sole phosphate exporter. Importantly, pharmacologic inhibition of XPR1 by XRBD, a peptide molecule that binds the extracellular domain 3 (ECL3) of XPR1 to antagonize its function, phenocopies the lethal impact of XPR1 knockdown on SLC34A2 overexpressing cancer cells. This observation supported the hypothesis that an antibody that binds to XPR1 will antagonize its function and selectively kill cancer cells that overexpress SLC34A2. There are no XPR1 therapeutics reported in clinical development indicating a first-in-class opportunity for an XPR1 therapeutic antibody. The goal of this program was to identify an antagonist antibody that inhibits XPR1 phosphate export function as a novel therapy for ovarian and uterine cancers patients with tumors that overexpress SLC34A2 (SLC34A2-high). We utilized XRBD to understand XPR1 biology in SLC34A2- high and low expressing cancer cell line models. Mechanistically, in SLC34A2-high expressing cell lines, genetic or pharmacologic inhibition of XPR1-dependent phosphate efflux led to the toxic accumulation of intracellular phosphate. XPR1 inhibition in these cell lines also resulted in increased cellular nucleotide triphosphate levels. Interestingly, we found altered mitochondrial gene expression and metabolism upon XPR1 inhibition and/or loss. Further, XPR1 inhibition induced gamma H2AX suggesting increased DNA damage. This finding was also supported by synergistic growth inhibition and cytotoxicity when XPR1 inhibitor was combined with cisplatin. On our path to therapeutic XPR1 antibody discovery, we identified antibodies that bound to overexpressed and endogenous XPR1, however they did not induce expected pharmacodynamic responses or efficacy against SLC34A2 -high expressing cancer cell lines. These results indicate that the binding of these antibodies to XPR1 does not recapitulate the antagonistic activity of XRBD against the viability of SLC34A2 overexpressing cancer cells. Citation Format: Mansi Babbar, Dion Daniels, Katie Vowell, Rajesh Sundaresan, Shuzhen Wu, Feng Wang, James Lin, Jenny Laraio, Justin Munro, Joseph Kozole, John Kreeger, Geeta Sharma, Bryan Joosse, Florence Patel, Joseph Tomlinson, Katherine Welbeck, Richard Priest, Jennifer Percival-Alwyn, Trevor Wattam, Gurjinder Heer, Iain Moal, Sreenivas Nannapaneni, Benjamin Schwartz, Biju Mangatt, Anthony Mazurek. XPR1 and SLC34A2 (NaPi2B)- A tale of targeting the phosphate homeostasis in cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2976.

Foraminifera are ubiquitous marine protists that intracellularly accumulate phosphate1, an important macronutrient in marine ecosystems and in fertilizer potentially leaked into the ocean. Intracellular phosphate concentrations can be 100–1,000 times higher than in the surrounding water1. Here we show that phosphate storage in foraminifera is widespread, from tidal flats to the deep sea. The total amount of intracellular phosphate stored in the benthic foraminifer Ammonia confertitesta in the Wadden Sea during a bloom is as high as around 5% of the annual consumption of phosphorus (P) fertilizer in Germany. Budget calculations for the Southern North Sea and the Peruvian Oxygen Minimum Zone indicate that benthic foraminifera may buffer riverine P runoff for approximately 37 days at the Southern North Sea and for about 21 days at the Peruvian margin. This indicates that these organisms are probably relevant for marine P cycling—they potentially buffer anthropogenic eutrophication in coastal environments. Phosphate is stored as polyphosphate in cell organelles that are potentially acidocalcisomes. Their metabolic functions can range from regulation of osmotic pressure and intracellular pH to calcium and energy storage. In addition, storage of energetic P compounds, such as creatine phosphate and polyphosphate, is probably an adaptation of foraminifera to O2 depletion.

Precise regulation of intracellular phosphate (Pi) is critical for cellular function, with xenotropic and polytropic retrovirus receptor 1 (XPR1) serving as the sole Pi exporter in humans. The mechanism of Pi efflux, activated by inositol pyrophosphates (PP-IPs), has remained unclear. This study presents cryo-electron microscopy structures of XPR1 in multiple conformations, revealing a transmembrane pathway for Pi export and a dual-binding activation pattern for PP-IPs. A canonical binding site is located at the dimeric interface of Syg1/Pho81/XPR1 (SPX) domains, and a second site, biased toward PP-IPs, is found between the transmembrane and SPX domains. By integrating structural studies with electrophysiological analyses, we characterized XPR1 as an inositol phosphates (IPs)/PP-IPs-activated phosphate channel. The interplay among its transmembrane domains, SPX domains, and IPs/PP-IPs orchestrates the conformational transition between its closed and open states.

Streptomycetes are bacteria of significant biotechnological interest due to their production of bioactive specialised metabolites used in medicine and agriculture. In these bacteria, specialised metabolism and morphological differentiation are linked and typically repressed under high phosphate conditions. This study characterises a DeoR-like transcriptional regulator, SCO1897, in Streptomyces coelicolor, whose expression increases during sporulation. Disruption of sco1897 results in reduced biosynthesis of specialised metabolites, delayed sporulation, higher spore phosphate content, and impaired germination. Transcriptomic analysis revealed 1420 genes differentially expressed in the sco1897 mutant compared to the S. coelicolor wild-type strain. The sco1897 gene is located upstream and transcribed in the same direction as six genes, including sco1898-1900 encoding sub-units of an ABC transporter annotated as involved in carbohydrate transport. SCO1897 negatively regulates its own expression, that of the sco1898-1900 ABC transporter, and sco4142, encoding the PstS phosphate-binding protein. The overexpression of sco1898-1900 in the S. coelicolor wild-type strain leads to a significant increase in intracellular spore phosphate levels, similar to those observed in the sco1897 mutant. These findings suggest a complex regulatory network involving the sco1897-sco1900 region. Hypotheses are proposed to explain the various phenotypes of the sco1897 mutant and the complex regulation of the genes of the sco1897-sco1900 region.

This study explored the generation site and regulation mechanism of reactive oxygen species(ROS) in the apoptosis of colorectal cancer cells induced by furanodienone(Fur). RKO cells were treated with 200 μmol·L~(-1) of Fur, and the changes in intracellular nicotinamide adenine dinucleotide phosphate oxidase(NOX) activity were detected by the NOX activity detection method. The control group, Fur group, diphenyleneiodonium(DPI) inhibitor group for general NOX, mitochondrial-targeted antioxidant(MitoTEMPO) group, Fur+DPI group, Fur+MitoTEMPO group, and H_2O_2 positive control group were set up. Intracellular ROS levels were detected by the ROS fluorescent staining method, and NOX1-NOX5 protein expressions were detected by Western blot. The NOX1-specific inhibitor ML171 and NOX4-specific inhibitor(GLX351322) were further introduced, and the cell activity was determined by cell counting kit-8(CCK-8) assay. The effects of ROS level change on the protein expressions of NOX4 and peroxiredoxin 1(PRDX1) were measured by Western blot. BAY11-7082, which is an inhibitor of the inhibitor of nuclear factor κB protein α(IκBα), was used to explore the effect of the expression of phosphorylated nuclear factor κB(p-NF-κB) in the nucleus after the Fur treatment on the NOX4 protein level. The lentiviral plasmid and empty plasmid for PRDX1 gene silencing were constructed to transfect RKO cells, and stably transfected strains were screened. The impact of PRDX1 gene knockout on Fur-induced apoptosis was further analyzed using the flow cytometry assay. The findings demonstrate a considerable increase in mitochondrial ROS level in response to Fur treatment, with an increase in intracellular NOX activity. However, the mitochondrial ROS level is significantly reduced in the Fur+DPI group. The results from Western blot and CCK-8 analysis suggest that intracellular NOX1 and NOX4 protein expressions are elevated by Fur treatment, and GLX351322 effectively reverses the pro-apoptotic effect of Fur, while ML171 has a minimal impact on apoptosis rate. Meanwhile, Fur significantly boosts the level of p-NF-κB in the nucleus, whereas the protein levels of p-NF-κB and NOX4 are reduced after the BAY treatment. The regulation of Fur on NOX4 and PRDX1 protein expressions is negatively correlated. In the stably transfected cell strain with PRDX1 gene knockout, the apoptosis rate is considerably higher than that of the negative control group after Fur treatment. The above results indicate that Fur can induce the apoptosis of colorectal cancer cells by promoting the signal transduction of NF-κB in the nucleus and increasing the generation of mitochondrial ROS derived from NOX4 to inhibit the PRDX1 protein expression.

Abstract Disclosure: S. Afreen: Research Investigator; Self; Tandem Diabetes Care, Yes. N. Afreen: None. Introduction: Hyperventilation is over-breathing in excess of the metabolic needs of the body, which can result in respiratory alkalosis and a wide range of electrolyte abnormalities. Case: A 38 year old male with a past history of hypertension, OSA and cholecystectomy reported having episodes of palpitations, tachypnea with respiratory rate as high as 80 breaths/ minute, associated with facial numbness and tingling, tetany, progressing to paralysis of his extremities. These episodes started 7 years ago but gradually became more frequent. He denied anxiety or stressors prior to these episodes. The episodes almost always result in emergency room visits. During one of these episodes he was found to have the following labs: ionized calcium-1 mmol/l, serum phosphorus- 0.8 mg/dl, serum potassium- 2.7 mmol/l, 1.25(OH)2D- 44pg/ml, alkaline phosphatase- 60 IU/l, glucose- 94 mg/dl and GFR- 90 ml/min/1.73m2. VBG during this episode: pH - 7.59, PCO2- 23 mm Hg, and bicarbonate - 22 mmol/l. Of note, the electrolytes are normal in between the episodes. Thyroid labs are normal. Off of phosphate supplementation for 3 days, in between episodes, his serum phos- 4.2mg/dl, cr - 0.84 mg/dl. Second morning urine phos - 84 mg/dl and urine cr - 206.81 mg/dl. Tubular phosphate reabsorption was 91.9%. He had negative Holter, nuclear stress testing and MRI of the brain. No mutations were identified on genetic analysis of CACNA15, KCNJ2, RYR1, SCN4A. During his recent endocrine clinic visit, on physical exam: height- 5 feet 11 inches, weight- 366 lbs weight, BMI- 51.1 kg/m2, BP- 129/89 mm Hg, heart rate- 81 bpm and respiratory rate- 18 breaths/minute. He did have one palpable 1.5 cm left thyroid nodule. Otherwise, the exam was unremarkable. The patient was referred to pulmonology to be evaluated for potential diaphragmatic and lung causes of his tachypnea. He was also referred to psychiatry for evaluation of underlying anxiety. Since these episodes of hyperventilation associated electrolyte abnormalities lead to paralysis, he was started on calcitriol 0.25mcg daily along with 1250 mg potassium phosphate daily. Discussion: Hyperventilation can lead to a respiratory alkalosis and corresponding increase in intracellular pH. High intracellular pH can lead to increased phosphofructokinase activity and glycolysis, resulting in increased intracellular phosphate shift. Acute respiratory alkalosis can also result in ionized calcium binding to albumin. Moreover, acute respiratory alkalosis results in reduction in hydrogen ion in the intracellular fluid with extracellular potassium ion shift into cells leading to hypokalemia.These electrolyte abnormalities can cause myopathies, cardiac arrhythmias, respiratory failure, paralysis, seizures, coma and death. Physicians should be aware of the possibility of electrolyte imbalance due to hyperventilation to prevent the development of life threatening complications. Presentation: 6/1/2024

Primary familial brain calcification (PFBC) is a monogenic disorder characterized by bilateral calcifications in the brain. The genetic basis remains unknown in over half of the PFBC patients, indicating the existence of additional novel causative genes. NAA60 was a recently reported novel causative gene for PFBC. The aim was to identify the probable novel causative gene in an autosomal recessive inherited PFBC family. We performed a comprehensive genetic study on a consanguineous Chinese family with 3 siblings diagnosed with PFBC. We evaluated the effect of the variant in a probable novel causative gene on the protein level using Western blot, immunofluorescence, and coimmunoprecipitation. Possible downstream pathogenic mechanisms were further explored in gene knockout (KO) cell lines and animal models. We identified a PFBC co-segregated homozygous variant of c.460_461del (p.D154Lfs*113) in NAA60. Functional assays showed that this variant disrupts NAA60 protein localization to Golgi and accelerated protein degradation. The mutant NAA60 protein alters its interaction with the PFBC-related proteins PiT2 and XPR1, affecting intracellular phosphate homeostasis. Further mass spectrometry analysis in NAA60 KO cell lines revealed decreased expression of multiple brain calcification-associated proteins, including reduced folate carrier (RFC), a folate metabolism-related protein. Our study replicated the identification of NAA60 as a novel causative gene for autosomal recessive PFBC, demonstrating our causative variant leads to NAA60 loss of function. The NAA60 loss of function disrupts not only PFBC-related proteins (eg, PiT2 and XPR1) but also a wide range of other brain calcification-associated membrane protein substrates (eg, RFC), and provided a novel probable pathogenic mechanism for PFBC. © 2024 International Parkinson and Movement Disorder Society.

Phosphates within tumors function as key biomolecules, playing a significant role in sustaining the viability of tumors. To disturb the homeostasis of cancer cells, regulating phosphate within the organism proves to be an effective strategy. Herein, we report single-atom Ce-doped Pt hydrides (Ce/Pt-H) with high phosphatase-like activity for phosphate hydrolysis. The resultant Ce/Pt-H exhibits a 26.90- and 6.25-fold increase in phosphatase-like activity in comparison to Ce/Pt and Pt-H, respectively. Mechanism investigations elucidate that the Ce Lewis acid site facilitates the coordination with phosphate groups, while the surface hydrides enhance the electron density of Pt for promoting catalytic ability in H2O cleavage and subsequent nucleophilic attack of hydroxyl groups. Finally, by leveraging its phosphatase-like activity, Ce/Pt-H can effectively regulate intracellular phosphates to disrupt redox homeostasis and amplify oxidative stress within cancer cells, ultimately leading to tumor apoptosis. This work provides fresh insights into noble-metal-based phosphatase mimics for inducing tumor apoptosis.

Every individual at some point encounters the progressive biological process of aging, which is considered one of the major risk factors for common diseases. The main drivers of aging are oxidative stress, senescence, and reactive oxygen species (ROS). The renin-angiotensin-aldosterone system (RAAS) includes several systematic processes for the regulation of blood pressure, which is caused by an imbalance of electrolytes. During activation of the RAAS, binding of angiotensin II (ANG II) to angiotensin II type 1 receptor (AGTR1) activates intracellular nicotinamide adenine dinucleotide phosphate (NADPH) oxidase to generate superoxide anions and promote uncoupling of endothelial nitric oxide (NO) synthase, which in turn decreases NO availability and increases ROS production. Promoting oxidative stress and DNA damage mediated by ANG II is tightly regulated. Individuals with sodium deficiency-associated diseases such as Gitelman syndrome (GS) and Bartter syndrome (BS) show downregulation of inflammation-related processes and have reduced oxidative stress and ROS. Additionally, the histone deacetylase sirtuin-1 (SIRT1) has a significant impact on the aging process, with reduced activity with age. However, GS/BS patients generally sustain higher levels of sirtuin-1 (SIRT1) activity than age-matched healthy individuals. SIRT1 expression in GS/BS patients tends to be higher than in healthy age-matched individuals; therefore, it can be assumed that there will be a trend towards healthy aging in these patients. In this review, we highlight the importance of the hallmarks of aging, inflammation, and the RAAS system in GS/BS patients and how this might impact healthy aging. We further propose future research directions for studying the etiology of GS/BS at the molecular level using patient-derived renal stem cells and induced pluripotent stem cells.

Xenotropic and polytropic retrovirus receptor 1 (XPR1) is the only known transporter associated with Pi efflux in mammals, and its impact on tumor progression is gradually being revealed. However, the role of XPR1 in hepatocellular carcinoma (HCC) is unknown. A bioinformatics screen for the phosphate exporter XPR1 was performed in HCC patients. The expression of XPR1 in clinical specimens was analyzed using quantitative real-time PCR, Western blot analysis, and immunohistochemical assays. Knockdown of the phosphate exporter XPR1 was performed by shRNA transfection to investigate the cellular phenotype and phosphate-related cytotoxicity of the Huh7 and HLF cell lines. In vivo tests were conducted to investigate the tumorigenicity of HCC cells xenografted into immunocompromised mice after silencing XPR1. Compared with that in paracancerous tissue, XPR1 expression in HCC tissues was markedly upregulated. High XPR1 expression significantly correlated with poor patient survival. Silencing of XPR1 leads to decreased proliferation, migration, invasion, and colony formation in HCC cells. Mechanistically, knockdown of XPR1 causes an increase in intracellular phosphate levels; mitochondrial dysfunction characterized by reduced mitochondrial membrane potential and adenosine triphosphate levels; increased reactive oxygen species levels; abnormal mitochondrial morphology; and downregulation of key mitochondrial fusion, fission, and inner membrane genes. This ultimately results in mitochondria-dependent apoptosis. These findings reveal the prognostic value of XPR1 in HCC progression and, more importantly, suggest that XPR1 might be a potential therapeutic target.

Contribution of Cd passivating functional bacterium H27 to tobacco growth under Cd stress

BackgroundLetrozole, an aromatase inhibitor, is used to treat breast cancer in postmenopausal women. Tumor lysis syndrome (TLS) is a complication that can trigger multiple organ failure caused by the release of intracellular nucleic acids, phosphate, and potassium into the blood due to rapid tumor cell disintegration induced by drug therapy. TLS is uncommon in solid tumors and occurs primarily in patients receiving chemotherapy. Herein, we report a rare occurrence of TLS that developed in a patient with locally advanced breast cancer following treatment with letrozole.Case presentationAn 80-year-old woman with increased bleeding from a fist-sized left-sided breast mass presented to our hospital. Histological examination led to a diagnosis of invasive ductal carcinoma of the luminal type. The patient refused chemotherapy and was administered hormonal therapy with letrozole. Seven days after letrozole initiation, she complained of anorexia and diarrhea. Blood test results revealed elevated blood urea nitrogen (BUN) and creatinine (Cr) levels, and she was admitted to our hospital for intravenous infusions. On the second day after admission, marked elevations of LDH, BUN, Cr, potassium, calcium, and uric acid levels were observed. Furthermore, metabolic acidosis and prolonged coagulation capacity were observed. We suspected TLS and discontinued letrozole, and the patient was treated with hydration, febuxostat, and maintenance hemodialysis. On the third day after admission, her respiratory status worsened because of acute respiratory distress syndrome associated with hypercytokinemia, and she was intubated. On the fourth day after admission, her general condition did not improve, and she died.ConclusionsAlthough TLS typically occurs after chemotherapy initiation, the findings from the present case confirm that this syndrome can also occur after hormonal therapy initiation and should be treated with caution.

Disruptions of phosphate homeostasis are associated with a multitude of diseases with insufficient treatments. Our knowledge regarding the mechanisms underlying metazoan phosphate homeostasis and sensing is limited. Here, we highlight four major advancements in this field during the last 12-18 months. First, kidney glycolysis senses filtered phosphate, which results in the release of glycerol 3-phosphate (G-3-P). Circulating G-3-P then stimulates synthesis of the phosphaturic hormone fibroblast growth factor 23 in bone. Second, the liver serves as a postprandial phosphate reservoir to limit serum phosphate excursions. It senses phosphate ingestion and triggers renal excretion of excess phosphate through a nerve-dependent mechanism. Third, phosphate-starvation in cells massively induces the phosphate transporters SLC20A1/PiT1 and SLC20A2/PiT2, implying direct involvement of cellular phosphate sensing. Under basal phosphate-replete conditions, PiT1 is produced but immediately destroyed, which suggests a novel mechanism for the regulation of PiT1 abundance. Fourth, Drosophila melanogaster intestinal cells contain novel organelles called PXo bodies that limit intracellular phosphate excursions. Phosphate starvation leads to PXo body dissolution, which triggers midgut proliferation. These studies have opened novel avenues to dissect the mechanisms that govern metazoan phosphate sensing and homeostasis with the potential to identify urgently needed therapeutic targets.

ObjectiveCarbohydrate Response Element Binding Protein (ChREBP) is a glucose 6-phosphate (G6P)-sensitive transcription factor that acts as a metabolic switch to maintain intracellular glucose and phosphate homeostasis. Hepatic ChREBP is well-known for its regulatory role in glycolysis, the pentose phosphate pathway, and de novo lipogenesis. The physiological role of ChREBP in hepatic glycogen metabolism and blood glucose regulation has not been assessed in detail, and ChREBP's contribution to carbohydrate flux adaptations in hepatic Glycogen Storage Disease type 1 (GSD I) requires further investigation. MethodsThe current study aimed to investigate the role of ChREBP as a regulator of glycogen metabolism in response to hepatic G6P accumulation, using a model for acute hepatic GSD type Ib. The immediate biochemical and regulatory responses to hepatic G6P accumulation were evaluated upon G6P transporter inhibition by the chlorogenic acid S4048 in mice that were either treated with a short hairpin RNA (shRNA) directed against ChREBP (shChREBP) or a scrambled shRNA (shSCR). Complementary stable isotope experiments were performed to quantify hepatic carbohydrate fluxes in vivo. ResultsShChREBP treatment normalized the S4048-mediated induction of hepatic ChREBP target genes to levels observed in vehicle- and shSCR-treated controls. In parallel, hepatic shChREBP treatment in S4048-infused mice resulted in a more pronounced accumulation of hepatic glycogen and further reduction of blood glucose levels compared to shSCR treatment. Hepatic ChREBP knockdown modestly increased glucokinase (GCK) flux in S4048-treated mice while it enhanced UDP-glucose turnover as well as glycogen synthase and phosphorylase fluxes. Hepatic GCK mRNA and protein levels were induced by shChREBP treatment in both vehicle- and S4048-treated mice, while glycogen synthase 2 (GYS2) and glycogen phosphorylase (PYGL) mRNA and protein levels were reduced. Finally, knockdown of hepatic ChREBP expression reduced starch domain binding protein 1 (STBD1) mRNA and protein levels while it inhibited acid alpha-glucosidase (GAA) activity, suggesting reduced capacity for lysosomal glycogen breakdown. ConclusionsOur data show that ChREBP activation controls hepatic glycogen and blood glucose levels in acute hepatic GSD Ib through concomitant regulation of glucose phosphorylation, glycogenesis, and glycogenolysis. ChREBP-mediated control of GCK enzyme levels aligns with corresponding adaptations in GCK flux. In contrast, ChREBP activation in response to acute hepatic GSD Ib exerts opposite effects on GYS2/PYGL enzyme levels and their corresponding fluxes, indicating that GYS2/PYGL expression levels are not limiting to their respective fluxes under these conditions.