Fructose-1,6-bisphosphatase 1 dephosphorylates and inhibits TERT for tumor suppression.

Telomere dysfunction is intricately linked to the aging process and stands out as a prominent cancer hallmark. Here we demonstrate that telomerase activity is differentially regulated in cancer and normal cells depending on the expression status of fructose-1,6-bisphosphatase 1 (FBP1). In FBP1-expressing cells, FBP1 directly interacts with and dephosphorylates telomerase reverse transcriptase (TERT) at Ser227. Dephosphorylated TERT fails to translocate into the nucleus, leading to the inhibition of telomerase activity, reduction in telomere lengths, enhanced senescence and suppressed tumor cell proliferation and growth in mice. Lipid nanoparticle-mediated delivery of FBP1 mRNA inhibits liver tumor growth. Additionally, FBP1 expression levels inversely correlate with TERT pSer227 levels in renal and hepatocellular carcinoma specimens and with poor prognosis of the patients. These findings demonstrate that FBP1 governs cell immortality through its protein phosphatase activity and uncover a unique telomerase regulation in tumor cells attributed to the downregulation or deficiency of FBP1 expression.

VHL suppresses autophagy and tumor growth through PHD1-dependent Beclin1 hydroxylation.

The Von Hippel-Lindau (VHL) protein, which is frequently mutated in clear-cell renal cell carcinoma (ccRCC), is a master regulator of hypoxia-inducible factor (HIF) that is involved in oxidative stresses. However, whether VHL possesses HIF-independent tumor-suppressing activity remains largely unclear. Here, we demonstrate that VHL suppresses nutrient stress-induced autophagy, and its deficiency in sporadic ccRCC specimens is linked to substantially elevated levels of autophagy and correlates with poorer patient prognosis. Mechanistically, VHL directly binds to the autophagy regulator Beclin1, after its PHD1-mediated hydroxylation on Pro54. This binding inhibits the association of Beclin1-VPS34 complexes with ATG14L, thereby inhibiting autophagy initiation in response to nutrient deficiency. Expression of non-hydroxylatable Beclin1 P54A abrogates VHL-mediated autophagy inhibition and significantly reduces the tumor-suppressing effect of VHL. In addition, Beclin1 P54-OH levels are inversely correlated with autophagy levels in wild-type VHL-expressing human ccRCC specimens, and with poor patient prognosis. Furthermore, combined treatment of VHL-deficient mouse tumors with autophagy inhibitors and HIF2α inhibitors suppresses tumor growth. These findings reveal an unexpected mechanism by which VHL suppresses tumor growth, and suggest a potential treatment for ccRCC through combined inhibition of both autophagy and HIF2α.

AMPK phosphorylation of FNIP1 (S220) controls mitochondrial function and muscle fuel utilization during exercise.

Exercise-induced activation of adenosine monophosphate-activated protein kinase (AMPK) and substrate phosphorylation modulate the metabolic capacity of mitochondria in skeletal muscle. However, the key effector(s) of AMPK and the regulatory mechanisms remain unclear. Here, we showed that AMPK phosphorylation of the folliculin interacting protein 1 (FNIP1) serine-220 (S220) controls mitochondrial function and muscle fuel utilization during exercise. Loss of FNIP1 in skeletal muscle resulted in increased mitochondrial content and augmented metabolic capacity, leading to enhanced exercise endurance in mice. Using skeletal muscle-specific nonphosphorylatable FNIP1 (S220A) and phosphomimic (S220D) transgenic mouse models as well as biochemical analysis in primary skeletal muscle cells, we demonstrated that exercise-induced FNIP1 (S220) phosphorylation by AMPK in muscle regulates mitochondrial electron transfer chain complex assembly, fuel utilization, and exercise performance without affecting mechanistic target of rapamycin complex 1-transcription factor EB signaling. Therefore, FNIP1 is a multifunctional AMPK effector for mitochondrial adaptation to exercise, implicating a mechanism for exercise tolerance in health and disease.

Characterization of hypoxia-responsive states in ovarian cancer to identify hot tumors and aid adjuvant therapy.

BACKGROUNDS: The hypoxia-responsive state of cancer is a complex pathophysiological process involving numerous genes playing different roles. Due to the rapid proliferation of cancer cells and chaotic angiogenesis, the clinical features of hypoxia-responsive states are not yet clear in patients with ovarian cancer. METHODS: Based on the RNA expression levels of 14 hypoxic markers, our study screened out hypoxia-related genes and construct a hypoxic score pattern to quantify the hypoxia-responsive states of a single tumor. Combining clinical prognosis, tumor mutation burden, microsatellite instability, the expression level of the immune checkpoint, IC50, and other indicators to evaluate the impact of different hypoxia-responsive states on clinical prognosis and therapeutic sensitivity. RESULTS: Our study identified a subgroup with an active hypoxia-responsive state and they have a worse clinical prognosis but exhibit higher immunogenicity and higher sensitivity to immunotherapy. CONCLUSIONS: This work revealed that hypoxia-responsive states played an important role in formation of tumor immunogenicity. Evaluating the hypoxia-responsive state will contribute to guiding more effective immunotherapy strategies.

Therapeutic effects of orthokeratology lens combined with 0.01% atropine eye drops on juvenile myopia / Efeitos terapêuticos da lente de ortoceratologia combinados com colírio atropina 0,01% em miopia juvenil

ABSTRACT Purpose: To explore the therapeutic effects of orthokeratology lens combined with 0.01% atropine eye drops on juvenile myopia. Methods: A total of 340 patients with juvenile myopia (340 eyes) treated from 2018 to December 2020 were divided into the control group (170 cases with 170 eyes, orthokeratology lens) and observation group (170 cases with 170 eyes, orthokeratology lens combined with 0.01% atropine eye drops). The best-corrected distance visual acuity, best-corrected near visual acuity, diopter, axial length, amplitude of accommodation, bright pupil diameter, dark pupil diameter, tear-film lipid layer thickness, and tear break-up time were measured before treatment and after 1 year of treatment. The incidence of adverse reactions was observed. Results: Compared with the values before treatment, the spherical equivalent degree was significantly improved by 0.22 (0.06, 0.55) D and 0.40 (0.15, 0.72) D in the observation and control groups after the treatment, respectively (p<0.01). After the treatment, the axial length was significantly increased by (0.15 ± 0.12) mm and (0.24 ± 0.11) mm in the observation and control groups, respectively, (p<0.01). After the treatment, the amplitude of accommodation significantly declined in the observation group and was lower than that in the control group, whereas both bright and dark pupil diameters significantly increase and were larger than those in the control group (p<0.01). After the treatment, the tear-film lipid layer thickness and tear break-up time significantly declined in the two groups (p<0.01). Conclusions: Orthokeratology lens combined with 0.01% atropine eye drops can synergistically enhance the control effect on juvenile myopia with high safety.

RESUMO Objetivo: Explorar os efeitos terapêuticos das lentes de ortoceratologia combinados com colírio atropina 0,01% em miopia juvenil. Métodos: Um total de 340 pacientes com miopia juvenil (340 olhos) tratados entre 2018 e Dezembro de 2020 foram divididos em Grupo Controle (170 casos com 170 olhos, lentes de ortoceratologia) e Grupo Observação (170 casos com 170 olhos, lentes de ortoceratologia combinadas com colírio atropina 0,01%). A acuidade visual melhor corrigida para longe, acuidade visual melhor corrigida para perto, dioptria, comprimento axial, amplitude de acomodação, diâmetro da pupila brilhante, diâmetro da pupila escura, espessura da camada lipídica da película lacrimal e tempo de ruptura do rasgo foram medidos antes do tratamento e 1 ano depois. A incidência de reações adversas foi observada. Resultados: Antes do tratamento, o grau esférico equivalente foi significativamente melhorado em 0,22 (0,06, 0,55) D e 0,40 (0,15, 0,72) D respectivamente no Grupo Observação e no Grupo Controle após o tratamento (p<0,01). Após tratamento, o comprimento axial foi significativamente aumentado em (0,15 ± 0,12) mm e (0,24 ± 0,11) mm respectivamente nos Grupos Observação e controle (p<0,01), enquanto, no grupo de observação, a amplitude de acomodação diminuiu significativamente e foi inferior a do Grupo Controle, e o diâmetro da pupila brilhante e o diâmetro da pupila escura aumentaram significativamente e foram maiores do que os do Grupo Controle (p<0,01). A espessura da camada lipídica da película lacrimal e o tempo de ruptura do rasgo diminuíram significativamente nos dois grupos (p<0,01) após o tratamento. Conclusões: As lentes de ortoceratologia combinadas com colírio atropina 0,01% podem melhorar significativamente o efeito controle em miopia juvenil com elevada segurança.

FNIP1 abrogation promotes functional revascularization of ischemic skeletal muscle by driving macrophage recruitment.

Ischaemia of the heart and limbs attributable to compromised blood supply is a major cause of mortality and morbidity. The mechanisms of functional angiogenesis remain poorly understood, however. Here we show that FNIP1 plays a critical role in controlling skeletal muscle functional angiogenesis, a process pivotal for muscle revascularization during ischemia. Muscle FNIP1 expression is down-regulated by exercise. Genetic overexpression of FNIP1 in myofiber causes limited angiogenesis in mice, whereas its myofiber-specific ablation markedly promotes the formation of functional blood vessels. Interestingly, the increased muscle angiogenesis is independent of AMPK but due to enhanced macrophage recruitment in FNIP1-depleted muscles. Mechanistically, myofiber FNIP1 deficiency induces PGC-1α to activate chemokine gene transcription, thereby driving macrophage recruitment and muscle angiogenesis program. Furthermore, in a mouse hindlimb ischemia model of peripheral artery disease, the loss of myofiber FNIP1 significantly improved the recovery of blood flow. Thus, these results reveal a pivotal role of FNIP1 as a negative regulator of functional angiogenesis in muscle, offering insight into potential therapeutic strategies for ischemic diseases.

Creatine kinase B suppresses ferroptosis by phosphorylating GPX4 through a moonlighting function.

Activation of receptor protein kinases is prevalent in various cancers with unknown impact on ferroptosis. Here we demonstrated that AKT activated by insulin-like growth factor 1 receptor signalling phosphorylates creatine kinase B (CKB) T133, reduces metabolic activity of CKB and increases CKB binding to glutathione peroxidase 4 (GPX4). Importantly, CKB acts as a protein kinase and phosphorylates GPX4 S104. This phosphorylation prevents HSC70 binding to GPX4, thereby abrogating the GPX4 degradation regulated by chaperone-mediated autophagy, alleviating ferroptosis and promoting tumour growth in mice. In addition, the levels of GPX4 are positively correlated with the phosphorylation levels of CKB T133 and GPX4 S104 in human hepatocellular carcinoma specimens and associated with poor prognosis of patients with hepatocellular carcinoma. These findings reveal a critical mechanism by which tumour cells counteract ferroptosis by non-metabolic function of CKB-enhanced GPX4 stability and underscore the potential to target the protein kinase activity of CKB for cancer treatment.

Proteolytic rewiring of mitochondria by LONP1 directs cell identity switching of adipocytes.

Mitochondrial proteases are emerging as key regulators of mitochondrial plasticity and acting as both protein quality surveillance and regulatory enzymes by performing highly regulated proteolytic reactions. However, it remains unclear whether the regulated mitochondrial proteolysis is mechanistically linked to cell identity switching. Here we report that cold-responsive mitochondrial proteolysis is a prerequisite for white-to-beige adipocyte cell fate programming during adipocyte thermogenic remodelling. Thermogenic stimulation selectively promotes mitochondrial proteostasis in mature white adipocytes via the mitochondrial protease LONP1. Disruption of LONP1-dependent proteolysis substantially impairs cold- or ß3 adrenergic agonist-induced white-to-beige identity switching of mature adipocytes. Mechanistically, LONP1 selectively degrades succinate dehydrogenase complex iron sulfur subunit B and ensures adequate intracellular succinate levels. This alters the histone methylation status on thermogenic genes and thereby enables adipocyte cell fate programming. Finally, augmented LONP1 expression raises succinate levels and corrects ageing-related impairments in white-to-beige adipocyte conversion and adipocyte thermogenic capacity. Together, these findings reveal that LONP1 links proteolytic surveillance to mitochondrial metabolic rewiring and directs cell identity conversion during adipocyte thermogenic remodelling.

Therapeutic effects of orthokeratology lens combined with 0.01% atropine eye drops on juvenile myopia.

PURPOSE: To explore the therapeutic effects of orthokeratology lens combined with 0.01% atropine eye drops on juvenile myopia. METHODS: A total of 340 patients with juvenile myopia (340 eyes) treated from 2018 to December 2020 were divided into the control group (170 cases with 170 eyes, orthokeratology lens) and observation group (170 cases with 170 eyes, orthokeratology lens combined with 0.01% atropine eye drops). The best-corrected distance visual acuity, best-corrected near visual acuity, diopter, axial length, amplitude of accommodation, bright pupil diameter, dark pupil diameter, tear-film lipid layer thickness, and tear break-up time were measured before treatment and after 1 year of treatment. The incidence of adverse reactions was observed. RESULTS: Compared with the values before treatment, the spherical equivalent degree was significantly improved by 0.22 (0.06, 0.55) D and 0.40 (0.15, 0.72) D in the observation and control groups after the treatment, respectively (p<0.01). After the treatment, the axial length was significantly increased by (0.15 ± 0.12) mm and (0.24 ± 0.11) mm in the observation and control groups, respectively, (p<0.01). After the treatment, the amplitude of accommodation significantly declined in the observation group and was lower than that in the control group, whereas both bright and dark pupil diameters significantly increase and were larger than those in the control group (p<0.01). After the treatment, the tear-film lipid layer thickness and tear break-up time significantly declined in the two groups (p<0.01). CONCLUSIONS: Orthokeratology lens combined with 0.01% atropine eye drops can synergistically enhance the control effect on juvenile myopia with high safety.

Nucleus-exported CLOCK acetylates PRPS to promote de novo nucleotide synthesis and liver tumour growth.

Impairment of the circadian clock is linked to cancer development. However, whether the circadian clock is modulated by oncogenic receptor tyrosine kinases remains unclear. Here we demonstrated that receptor tyrosine kinase activation promotes CK2-mediated CLOCK S106 phosphorylation and subsequent disassembly of the CLOCK-BMAL1 dimer and suppression of the downstream gene expression in hepatocellular carcinoma (HCC) cells. In addition, CLOCK S106 phosphorylation exposes its nuclear export signal to bind Exportin1 for nuclear exportation. Cytosolic CLOCK acetylates PRPS1/2 K29 and blocks HSC70-mediated and lysosome-dependent PRPS1/2 degradation. Stabilized PRPS1/2 promote de novo nucleotide synthesis and HCC cell proliferation and liver tumour growth. Furthermore, CLOCK S106 phosphorylation and PRPS1/2 K29 acetylation are positively correlated in human HCC specimens and with HCC poor prognosis. These findings delineate a critical mechanism by which oncogenic signalling inhibits canonical CLOCK transcriptional activity and simultaneously confers CLOCK with instrumental moonlighting functions to promote nucleotide synthesis and tumour growth.

The contributions of ammonia oxidizing bacteria and archaea to nitrification-dependent N2O emission in alkaline and neutral purple soils.

Nitrification is believed to be one of the primary processes of N2O emission in the agroecological system, which is controlled by soil microbes and mainly regulated by soil pH, oxygen content and NH4+ availability. Previous studies have proved that the relative contributions of ammonia oxidizing bacteria (AOB) and archaea (AOA) to N2O production were varied with soil pH, however, there is still no consensus on the regulating mechanism of nitrification-derived N2O production by soil pH. In this study, 1-octyne (a selective inhibitor of AOB) and acetylene (an inhibitor of AOB and AOA) were used in a microcosm incubation experiment to differentiate the relative contribution of AOA and AOB to N2O emissions in a neutral (pH = 6.75) and an alkaline (pH = 8.35) soils. We found that the amendment of ammonium (NH4+) observably stimulated the production of both AOA and AOB-related N2O and increased the ammonia monooxygenase (AMO) gene abundances of AOA and AOB in the two test soils. Among which, AOB dominated the process of ammonia oxidation in the alkaline soil, contributing 70.8% of N2O production derived from nitrification. By contrast, the contribution of AOA and AOB accounted for about one-third of nitrification-related N2O in acidic soil, respectively. The results indicated that pH was a key factor to change abundance and activity of AOA and AOB, which led to the differentiation of derivation of N2O production in purple soils. We speculate that both NH4+ content and soil pH mediated specialization of ammonia-oxidizing microorganisms together; and both specialization results and N2O yield led to the different N2O emission characteristics in purple soils. These results may help inform the development of N2O reduction strategies in the future.

Silencing EGFR-upregulated expression of CD55 and CD59 activates the complement system and sensitizes lung cancer to checkpoint blockade.

The complement system is a critical immune component, yet its role in tumor immune evasion and CD8+ T cell activation is not clearly defined. Here, we demonstrate that epidermal growth factor receptor (EGFR)/Wnt signaling induces ß-catenin-mediated long noncoding RNA (lncRNA) LINC00973 expression to sponge CD55-targeting miR-216b and CD59-targeting miR-150. The consequently upregulated CD55/CD59 expression suppresses the complement system and cytokine secretion required for CD8+ T cell activation. CD55/CD59-neutralizing antibody treatment or mutation of the LINC00973 promoter activates the complement and CD8+ T cells, inhibiting tumor growth. Importantly, combined anti-CD55/CD59 and anti-programmed death 1 (anti-PD-1) antibody treatments elicit a synergistic tumor-inhibiting effect. In addition, CD55/CD59 levels are inversely correlated with infiltration of M1 macrophages and CD8+ T cells in human lung cancer specimens and predict patient outcome. These findings underscore the critical role of EGFR/Wnt/ß-catenin-upregulated CD55/CD59 expression in inhibiting the complement and CD8+ T cell activation for tumor immune evasion and immune checkpoint blockade resistance and identify a potential combination therapy to overcome these effects.

Aerobic glycolysis promotes tumor immune evasion by hexokinase2-mediated phosphorylation of IκBα.

High expression of PD-L1 in tumor cells contributes to tumor immune evasion. However, whether PD-L1 expression in tumor cells is regulated by the availability of nutrients is unknown. Here, we show that in human glioblastoma cells, high glucose promotes hexokinase (HK) 2 dissociation from mitochondria and its subsequent binding and phosphorylation of IκBα at T291. This leads to increased interaction between IκBα and µ-calpain protease and subsequent µ-calpain-mediated IκBα degradation and NF-κB activation-dependent transcriptional upregulation of PD-L1 expression. Expression of IκBα T291A in glioblastoma cells blocked high glucose-induced PD-L1 expression and promoted CD8+ T cell activation and infiltration into the tumor tissue, reducing brain tumor growth. Combined treatment with an HK inhibitor and an anti-PD-1 antibody eliminates tumor immune evasion and remarkably enhances the anti-tumor effect of immune checkpoint blockade. These findings elucidate a novel mechanism underlying the upregulation of PD-L1 expression mediated by aerobic glycolysis and underscore the roles of HK2 as a glucose sensor and a protein kinase in regulation of tumor immune evasion.

Mitochondrial proteostasis stress in muscle drives a long-range protective response to alleviate dietary obesity independently of ATF4.

Mitochondrial quality in skeletal muscle is crucial for maintaining energy homeostasis during metabolic stresses. However, how muscle mitochondrial quality is controlled and its physiological impacts remain unclear. Here, we demonstrate that mitoprotease LONP1 is essential for preserving muscle mitochondrial proteostasis and systemic metabolic homeostasis. Skeletal muscle-specific deletion of Lon protease homolog, mitochondrial (LONP1) impaired mitochondrial protein turnover, leading to muscle mitochondrial proteostasis stress. A benefit of this adaptive response was the complete resistance to diet-induced obesity. These favorable metabolic phenotypes were recapitulated in mice overexpressing LONP1 substrate ΔOTC in muscle mitochondria. Mechanistically, mitochondrial proteostasis imbalance elicits an unfolded protein response (UPRmt) in muscle that acts distally to modulate adipose tissue and liver metabolism. Unexpectedly, contrary to its previously proposed role, ATF4 is dispensable for the long-range protective response of skeletal muscle. Thus, these findings reveal a pivotal role of LONP1-dependent mitochondrial proteostasis in directing muscle UPRmt to regulate systemic metabolism.

FNIP1 regulates adipocyte browning and systemic glucose homeostasis in mice by shaping intracellular calcium dynamics.

Metabolically beneficial beige adipocytes offer tremendous potential to combat metabolic diseases. The folliculin interacting protein 1 (FNIP1) is implicated in controlling cellular metabolism via AMPK and mTORC1. However, whether and how FNIP1 regulates adipocyte browning is unclear. Here, we demonstrate that FNIP1 plays a critical role in controlling adipocyte browning and systemic glucose homeostasis. Adipocyte-specific ablation of FNIP1 promotes a broad thermogenic remodeling of adipocytes, including increased UCP1 levels, high mitochondrial content, and augmented capacity for mitochondrial respiration. Mechanistically, FNIP1 binds to and promotes the activity of SERCA, a main Ca2+ pump responsible for cytosolic Ca2+ removal. Loss of FNIP1 resulted in enhanced intracellular Ca2+ signals and consequential activation of Ca2+-dependent thermogenic program in adipocytes. Furthermore, mice lacking adipocyte FNIP1 were protected against high-fat diet-induced insulin resistance and liver steatosis. Thus, these findings reveal a pivotal role of FNIP1 as a negative regulator of beige adipocyte thermogenesis and unravel an intriguing functional link between intracellular Ca2+ dynamics and adipocyte browning.

Disuse-associated loss of the protease LONP1 in muscle impairs mitochondrial function and causes reduced skeletal muscle mass and strength.

Mitochondrial proteolysis is an evolutionarily conserved quality-control mechanism to maintain proper mitochondrial integrity and function. However, the physiological relevance of stress-induced impaired mitochondrial protein quality remains unclear. Here, we demonstrate that LONP1, a major mitochondrial protease resides in the matrix, plays a role in controlling mitochondrial function as well as skeletal muscle mass and strength in response to muscle disuse. In humans and mice, disuse-related muscle loss is associated with decreased mitochondrial LONP1 protein. Skeletal muscle-specific ablation of LONP1 in mice resulted in impaired mitochondrial protein turnover, leading to mitochondrial dysfunction. This caused reduced muscle fiber size and strength. Mechanistically, aberrant accumulation of mitochondrial-retained protein in muscle upon loss of LONP1 induces the activation of autophagy-lysosome degradation program of muscle loss. Overexpressing a mitochondrial-retained mutant ornithine transcarbamylase (ΔOTC), a known protein degraded by LONP1, in skeletal muscle induces mitochondrial dysfunction, autophagy activation, and cause muscle loss and weakness. Thus, these findings reveal a role of LONP1-dependent mitochondrial protein quality-control in safeguarding mitochondrial function and preserving skeletal muscle mass and strength, and unravel a link between mitochondrial protein quality and muscle mass maintenance during muscle disuse.

Displacement and stress distribution of mandibular incisors after orthodontic treatment in the presence of alveolar bone loss under occlusal loads: A finite element analysis.

INTRODUCTION: This study evaluated the initial stress produced in the periodontal ligament (PDL) and the displacements of mandibular incisors under masticatory force in patients with alveolar bone loss (ABL) after orthodontic treatment. METHODS: Four horizontal absorption models (zero, one third, one half, and two thirds of root length) and 2 labiolingual absorption models (labial two thirds, lingual one third of root length, and vice versa) of the mandibular anterior segment were constructed. A total force of 285.3 N was applied vertically to the edges of incisors. The tooth displacement and principal stresses in the PDL were evaluated in a finite element analysis. RESULTS: In all models, the labial movements of the central incisors ascended more significantly, whereas there was obvious compressive stress and tensile stress concentrated in the labial and lingual cervical margins of the PDL, respectively. For the lateral incisors, augmentation of the distal motions was more evident. Compressive stress was apparent in the labial-distal margin, and tensile stress was concentrated in the lingual-mesial cervical margin. With the same proportion of ABL, more significant displacement and stress concentration in the PDL occurred in the central incisors. In labiolingual absorption models, labial ABL caused greater incisors displacement and periodontal stress concentration. When horizontal ABL extended from one half to two thirds of the root length, mobility of the central incisors and stresses in the PDL increased significantly. CONCLUSIONS: Mandibular incisors follow the different movement and stress distribution patterns under occlusal loads. Special consideration should be given to the retention of mandibular incisors when horizontal ABL exceeds half of the root length.

Metformin-loaded ß-TCP/CTS/SBA-15 composite scaffolds promote alveolar bone regeneration in a rat model of periodontitis.

Periodontitis is a progressive infectious inflammatory disease, which leads to alveolar bone resorption and loss of periodontal attachment. It is imperative for us to develop a therapeutic scaffold to repair the alveolar bone defect of periodontitis. In this study, we designed a new composite scaffold loading metformin (MET) by using the freeze-drying method, which was composed of ß-tricalcium phosphate (ß-TCP), chitosan (CTS) and the mesoporous silica (SBA-15). The scaffolds were expected to combine the excellent biocompatibility of CTS, the good bioactivity of ß-TCP, and the anti-inflammatory properties of MET. The MET-loaded ß-TCP/CTS/SBA-15 scaffolds showed improved cell adhesion, appropriate porosity and good biocompatibility in vitro. This MET composite scaffold was implanted in the alveolar bone defects area of rats with periodontitis. After 12 weeks, Micro-CT and histological analysis were performed to evaluate different degrees of healing and mineralization. Results showed that the MET-loaded ß-TCP/CTS/SBA-15 scaffolds promoted alveolar bone regeneration in a rat model of periodontitis. To our knowledge, this is the first report that MET-loaded ß-TCP/CTS/SBA-15 scaffolds have a positive effect on alveolar bone regeneration in periodontitis. Our findings might provide a new and promising strategy for repairing alveolar bone defects under the condition of periodontitis.