1.Intra-articular injection of different concentrations of silicon-based bioceramics in treatment of knee osteoarthritis in rats
Jingwen GUO ; Qingwei WANG ; Zijun HE ; Zihang HU ; Zhi CHEN ; Rong ZHU ; Yuming WANG ; Wenfei LIU ; Qinglu LUO
Chinese Journal of Tissue Engineering Research 2026;30(2):288-295
BACKGROUND:Currently,treatment method for knee osteoarthritis includes oral medicine,joint cavity drug injection,and physiotherapy,but the curative effect is limited.Existing studies have confirmed that silicon-based bioceramics can promote cartilage and subchondral bone repair and vascular regeneration.OBJECTIVE:To explore the effect of different concentrations of silicon-based bioceramics injected into the knee joint cavity in the treatment of knee osteoarthritis in rats.METHODS:Silicon-based bioceramics-calcium silicate was prepared.Twenty-five SD rats were randomly divided into five groups,with five rats in each group.The healthy group did not receive any intervention,and the modeling group,low-dose calcium silicate group,high-dose calcium silicate group,and saline group used anterior cruciate ligament transection to establish bilateral knee osteoarthritis models.Four weeks after modeling,0.05 mL of 50 and 100 mg/mL calcium silicate solution were injected into the knee joint cavity in the low-dose calcium silicate group and high-dose calcium silicate group,respectively,and 0.05 mL of saline was injected into the knee joint cavity in the saline group,once a week for 4 consecutive weeks.In the fifth week of administration,bilateral knee joint Micro-CT detection,knee joint cartilage hematoxylin-eosin staining,and modified Mankin score were performed.RESULTS AND CONCLUSION:(1)Micro-CT quantitative analysis showed that compared with the healthy group,the volume fraction and number of trabeculae of the medial tibial plateau in the modeling group decreased(P<0.05),and the separation of trabeculae increased(P<0.05).Compared with the modeling group,the volume fraction and number of trabeculae of the medial tibial plateau in the low-dose calcium silicate group and the saline group increased(P<0.05),and the separation of trabeculae decreased(P<0.05).(2)Hematoxylin-eosin staining showed that the cartilage surface of the healthy group and the low-dose calcium silicate group was relatively smooth and flat,the chondrocytes were evenly distributed,without clustered chondrocytes,the tide line was complete,and the staining was uniform;the cartilage surface of the high-dose calcium silicate group was slightly uneven,the middle and deep cells were disordered,with a small number of clustered chondrocytes,the tide line was discontinuous,and the staining was uneven;the cartilage surface of the saline group and the modeling group was obviously rough,the cells were disordered,with a large number of clustered chondrocytes,the tide line disappeared,and the staining was uneven.The modified Mankin score of the healthy group was lower than that of the high-dose calcium silicate group,the saline group,and the modeling group(P<0.05).The modified Mankin score of the high-dose calcium silicate group and the low-dose calcium silicate group was lower than that of the saline group and the modeling group(P<0.05).(3)The results show that calcium silicate knee joint injection has a certain effect in the treatment of knee osteoarthritis.Compared with 100 mg/mL calcium silicate solution,50 mg/mL calcium silicate solution can promote the recovery of subchondral bone and cartilage.
2.Plasma metabolites,immune cells,and hip osteoarthritis:causal inference based on GWAS data from European populations
Xiangbin RONG ; Haibo ZHENG ; Xueshen MO ; Kun HOU ; Ping ZENG
Chinese Journal of Tissue Engineering Research 2026;30(4):1028-1035
BACKGROUND:Some studies have confirmed the changes in the function of immune cell subsets such as monocytes,T cells,B cells,and natural killer cells(NK cells)in patients with osteoarthritis,but the specific regulatory mechanisms are unclear.OBJECTIVE:To explore the causal relationship between plasma metabolite-mediated immune cells and hip osteoarthritis.METHODS:The Genome-Wide Association Studies(GWAS)data of 731 immune cells were used as the exposure,the GWAS data of hip osteoarthritis were used as the outcome,and 1 400 plasma metabolites were selected as mediating factors.The GWAS database is an important database for genetic association studies,maintained by international organizations with no country-specific affiliation.The inverse variance weighting method in the two-sample Mendelian randomization method was the main method,and the Bayesian weighted Mendelian randomization method was used to analyze the prior distribution,sample data and weights,which were then used to calculate the posterior distribution.The accuracy and reliability of the inverse variance weighting results were evaluated according to the posterior distribution,supplemented by MR-Egger,weighted median,simple model,and weighted mode methods.The pliotropy test and heterogeneity test were used to ensure the robustness of the process.The results of the inverse variance weighting method were used for subsequent mediating effect analysis.RESULTS AND CONCLUSION:(1)The inverse variance weighting method identified 4 immune cells strongly correlated with hip osteoarthritis,and 20 metabolites strongly associated with hip osteoarthritis,all of which had no reverse causal relationship.At the same time,the validation results of Bayesian weighted Mendelian randomization method showed that the posterior mean value was similar to the estimated value of the inverse variance weighting,and the posterior variance was relatively lower.One monocyte subtype(PDL-1 on CD14-CD16+)was finally screened out to have a causal relationship with hip osteoarthritis,with a total effect of-0.047(odds ratio=0.954,95%confidence interval:0.926-0.983),and a mediating effect of-0.004(odds ratio=0.939,95%confidence interval:0.902-0.978)mediated by alliin levels,accounting for 8.5%of the total effect.It was concluded that alliin is a protective factor in the progression of hip osteoarthritis,in which this metabolite plays a mediating role.(2)The large amount of data from international databases and European population analysis is of great significance to Chinese biomedicine,which can provide clues for research on the genetic susceptibility to similar diseases in the Chinese population,aiding in discovering the unique associations.The pharmacogenomic approaches used can be adapted to screen for drug response genes in the Chinese population,enhancing the precision of personalized medicine.Additionally,the advanced high-throughput technologies and statistical methods employed can be learned and applied to disease prevention and treatment research.
3.Macrophage autophagy in lung diseases:two-sided effects
Huijuan YOU ; Shuzhen WU ; Rong RONG ; Liyuan CHEN ; Yuqing ZHAO ; Qinglu WANG ; Xiaowei OU ; Fengying YANG
Chinese Journal of Tissue Engineering Research 2026;30(6):1516-1526
BACKGROUND:Macrophages play a key role in the occurrence and progression of lung diseases,and autophagy plays an important role in maintaining environmental homeostasis and functional stability in macrophages.It has been suggested that macrophage autophagic activity has two sides in lung inflammatory diseases.OBJECTIVE:To summarize the relationship between macrophage autophagy and lung diseases,thereby providing reference for exploring the prevention and treatment strategies of lung inflammatory diseases by targeting macrophage autophagy.METHODS:Literature retrieval was performed in CNKI and PubMed for relevant literature published from database inception to September 2024.The search terms were"macrophage autophagy,efferocytosis,macrophage polarization,acute lung injury,pneumonia,chronic obstructive pulmonary disease,pulmonary fibrosis,asthma"in Chinese and English,respectively.The search results were included or excluded based on the selection criteria,and 100 papers that met the criteria were finally included in the review.RESULTS AND CONCLUSION:(1)The obstruction of autophagy flow will induce the polarization imbalance of macrophages and impair their efferocytosis,resulting in the increase of M1 macrophages and aggravating inflammation.(2)The judgment of autophagic activity should be based on whether the autophagy flow is smooth or not,and it is essential to evaluate the degradation ability of autophagy.Some studies failed to comprehensively detect the degradation ability of autophagy lysosomes to assess whether the autophagy flow is unobtrusive.As a result,the so-called two-sided view of pulmonary macrophage autophagy in pulmonary inflammatory diseases in such studies is actually related to the one-sided judgment of autophagy activity.(3)The pathological manifestations vary across different pulmonary diseases and even at different stages of the same disease.Activation of macrophage autophagy plays a positive role in regulating pulmonary inflammatory homeostasis in conditions such as acute lung injury,infectious pneumonia,mild chronic obstructive pulmonary disease,early-stage pulmonary fibrosis,and secondary asthma.However,in the severe fibrotic stage of chronic obstructive pulmonary disease and the progressive stage of pulmonary fibrosis,the activation of pulmonary macrophage autophagy aggravates pulmonary fibrosis,reflecting the dual nature of macrophage autophagy.In allergic asthma,autophagy is activated in lung-resident macrophages but suppressed in infiltrating monocyte-derived macrophages from circulation.The former is closely related to airway stenosis,and the latter aggravates pneumonia disorders.Therefore,identifying the types and progression stages of lung diseases,along with accurately assessing autophagic activity,is crucial for future investigations into the relationship between macrophage autophagy and disease pathogenesis,thereby facilitating the development of therapeutic strategies in the future.
4.Mechanism of depression-like behavior in chronic social defeat stress mice based on high-throughput sequencing
Di ZHANG ; Jun ZHAO ; Guangyue MA ; Hui SUN ; Rong JIANG
Chinese Journal of Tissue Engineering Research 2026;30(5):1139-1146
BACKGROUND:Stress-induced damage to hippocampal neurons may underlie abnormalities in neuronal structure and function,ultimately leading to mood disorders.G protein-coupled receptors in brain tissue play an important role in mood regulation.OBJECTIVE:To analyze the mechanism of depression-like behavior in chronic social defeat stress mice based on high-throughput sequencing and bioinformatics analysis.METHODS:C57BL/6J mice were randomly divided into control group and model group.There was no special treatment in the control group,while a mouse model of chronic social defeat stress was established in the model group.Depression-like behavior was assessed through the sucrose preference test,tail suspension test,and forced swim test.Anxiety behavior was evaluated using the elevated plus-maze,while social behavior was measured through the social interaction test.Cognitive function was assessed with the Y-maze spontaneous alternation test.Immunofluorescence staining was performed to quantify microglia markers in the mouse hippocampus,and Nissl staining was used to examine neuronal damage in mice.High-throughput sequencing was used to identify differentially expressed genes and gene enrichment in the mouse hippocampus,and qPCR was used to measure the expression of G protein-coupled receptors in the mouse hippocampus.RESULTS AND CONCLUSION:(1)Compared with the control group,chronic social defeat stress mice showed significant behavioral impairments,including increased anxiety,depression,and cognitive deficits.(2)Additionally,the Nissl body light density in hippocampal neurons was significantly reduced in chronic social defeat stress mice.(3)Sequencing results revealed synaptic damage in the neurons after chronic social defeat stress.Microglia activation was also markedly increased in the hippocampus of CSDS mice.Furthermore,the expression of G protein-coupled receptors in the hippocampus was significantly higher in chronic social defeat stress mice compared with the control group.These findings suggest that chronic social defeat stress induces anxiety,depression,and cognitive deficits in mice,accompanied by neuropathological changes in the hippocampus,and that altered G protein-coupled receptors expression may play a key role in these behavioral and neuropathological changes.
5.Intra-articular injection of different concentrations of silicon-based bioceramics in treatment of knee osteoarthritis in rats
Jingwen GUO ; Qingwei WANG ; Zijun HE ; Zihang HU ; Zhi CHEN ; Rong ZHU ; Yuming WANG ; Wenfei LIU ; Qinglu LUO
Chinese Journal of Tissue Engineering Research 2026;30(2):288-295
BACKGROUND:Currently,treatment method for knee osteoarthritis includes oral medicine,joint cavity drug injection,and physiotherapy,but the curative effect is limited.Existing studies have confirmed that silicon-based bioceramics can promote cartilage and subchondral bone repair and vascular regeneration.OBJECTIVE:To explore the effect of different concentrations of silicon-based bioceramics injected into the knee joint cavity in the treatment of knee osteoarthritis in rats.METHODS:Silicon-based bioceramics-calcium silicate was prepared.Twenty-five SD rats were randomly divided into five groups,with five rats in each group.The healthy group did not receive any intervention,and the modeling group,low-dose calcium silicate group,high-dose calcium silicate group,and saline group used anterior cruciate ligament transection to establish bilateral knee osteoarthritis models.Four weeks after modeling,0.05 mL of 50 and 100 mg/mL calcium silicate solution were injected into the knee joint cavity in the low-dose calcium silicate group and high-dose calcium silicate group,respectively,and 0.05 mL of saline was injected into the knee joint cavity in the saline group,once a week for 4 consecutive weeks.In the fifth week of administration,bilateral knee joint Micro-CT detection,knee joint cartilage hematoxylin-eosin staining,and modified Mankin score were performed.RESULTS AND CONCLUSION:(1)Micro-CT quantitative analysis showed that compared with the healthy group,the volume fraction and number of trabeculae of the medial tibial plateau in the modeling group decreased(P<0.05),and the separation of trabeculae increased(P<0.05).Compared with the modeling group,the volume fraction and number of trabeculae of the medial tibial plateau in the low-dose calcium silicate group and the saline group increased(P<0.05),and the separation of trabeculae decreased(P<0.05).(2)Hematoxylin-eosin staining showed that the cartilage surface of the healthy group and the low-dose calcium silicate group was relatively smooth and flat,the chondrocytes were evenly distributed,without clustered chondrocytes,the tide line was complete,and the staining was uniform;the cartilage surface of the high-dose calcium silicate group was slightly uneven,the middle and deep cells were disordered,with a small number of clustered chondrocytes,the tide line was discontinuous,and the staining was uneven;the cartilage surface of the saline group and the modeling group was obviously rough,the cells were disordered,with a large number of clustered chondrocytes,the tide line disappeared,and the staining was uneven.The modified Mankin score of the healthy group was lower than that of the high-dose calcium silicate group,the saline group,and the modeling group(P<0.05).The modified Mankin score of the high-dose calcium silicate group and the low-dose calcium silicate group was lower than that of the saline group and the modeling group(P<0.05).(3)The results show that calcium silicate knee joint injection has a certain effect in the treatment of knee osteoarthritis.Compared with 100 mg/mL calcium silicate solution,50 mg/mL calcium silicate solution can promote the recovery of subchondral bone and cartilage.
6.Plasma metabolites,immune cells,and hip osteoarthritis:causal inference based on GWAS data from European populations
Xiangbin RONG ; Haibo ZHENG ; Xueshen MO ; Kun HOU ; Ping ZENG
Chinese Journal of Tissue Engineering Research 2026;30(4):1028-1035
BACKGROUND:Some studies have confirmed the changes in the function of immune cell subsets such as monocytes,T cells,B cells,and natural killer cells(NK cells)in patients with osteoarthritis,but the specific regulatory mechanisms are unclear.OBJECTIVE:To explore the causal relationship between plasma metabolite-mediated immune cells and hip osteoarthritis.METHODS:The Genome-Wide Association Studies(GWAS)data of 731 immune cells were used as the exposure,the GWAS data of hip osteoarthritis were used as the outcome,and 1 400 plasma metabolites were selected as mediating factors.The GWAS database is an important database for genetic association studies,maintained by international organizations with no country-specific affiliation.The inverse variance weighting method in the two-sample Mendelian randomization method was the main method,and the Bayesian weighted Mendelian randomization method was used to analyze the prior distribution,sample data and weights,which were then used to calculate the posterior distribution.The accuracy and reliability of the inverse variance weighting results were evaluated according to the posterior distribution,supplemented by MR-Egger,weighted median,simple model,and weighted mode methods.The pliotropy test and heterogeneity test were used to ensure the robustness of the process.The results of the inverse variance weighting method were used for subsequent mediating effect analysis.RESULTS AND CONCLUSION:(1)The inverse variance weighting method identified 4 immune cells strongly correlated with hip osteoarthritis,and 20 metabolites strongly associated with hip osteoarthritis,all of which had no reverse causal relationship.At the same time,the validation results of Bayesian weighted Mendelian randomization method showed that the posterior mean value was similar to the estimated value of the inverse variance weighting,and the posterior variance was relatively lower.One monocyte subtype(PDL-1 on CD14-CD16+)was finally screened out to have a causal relationship with hip osteoarthritis,with a total effect of-0.047(odds ratio=0.954,95%confidence interval:0.926-0.983),and a mediating effect of-0.004(odds ratio=0.939,95%confidence interval:0.902-0.978)mediated by alliin levels,accounting for 8.5%of the total effect.It was concluded that alliin is a protective factor in the progression of hip osteoarthritis,in which this metabolite plays a mediating role.(2)The large amount of data from international databases and European population analysis is of great significance to Chinese biomedicine,which can provide clues for research on the genetic susceptibility to similar diseases in the Chinese population,aiding in discovering the unique associations.The pharmacogenomic approaches used can be adapted to screen for drug response genes in the Chinese population,enhancing the precision of personalized medicine.Additionally,the advanced high-throughput technologies and statistical methods employed can be learned and applied to disease prevention and treatment research.
7.Macrophage autophagy in lung diseases:two-sided effects
Huijuan YOU ; Shuzhen WU ; Rong RONG ; Liyuan CHEN ; Yuqing ZHAO ; Qinglu WANG ; Xiaowei OU ; Fengying YANG
Chinese Journal of Tissue Engineering Research 2026;30(6):1516-1526
BACKGROUND:Macrophages play a key role in the occurrence and progression of lung diseases,and autophagy plays an important role in maintaining environmental homeostasis and functional stability in macrophages.It has been suggested that macrophage autophagic activity has two sides in lung inflammatory diseases.OBJECTIVE:To summarize the relationship between macrophage autophagy and lung diseases,thereby providing reference for exploring the prevention and treatment strategies of lung inflammatory diseases by targeting macrophage autophagy.METHODS:Literature retrieval was performed in CNKI and PubMed for relevant literature published from database inception to September 2024.The search terms were"macrophage autophagy,efferocytosis,macrophage polarization,acute lung injury,pneumonia,chronic obstructive pulmonary disease,pulmonary fibrosis,asthma"in Chinese and English,respectively.The search results were included or excluded based on the selection criteria,and 100 papers that met the criteria were finally included in the review.RESULTS AND CONCLUSION:(1)The obstruction of autophagy flow will induce the polarization imbalance of macrophages and impair their efferocytosis,resulting in the increase of M1 macrophages and aggravating inflammation.(2)The judgment of autophagic activity should be based on whether the autophagy flow is smooth or not,and it is essential to evaluate the degradation ability of autophagy.Some studies failed to comprehensively detect the degradation ability of autophagy lysosomes to assess whether the autophagy flow is unobtrusive.As a result,the so-called two-sided view of pulmonary macrophage autophagy in pulmonary inflammatory diseases in such studies is actually related to the one-sided judgment of autophagy activity.(3)The pathological manifestations vary across different pulmonary diseases and even at different stages of the same disease.Activation of macrophage autophagy plays a positive role in regulating pulmonary inflammatory homeostasis in conditions such as acute lung injury,infectious pneumonia,mild chronic obstructive pulmonary disease,early-stage pulmonary fibrosis,and secondary asthma.However,in the severe fibrotic stage of chronic obstructive pulmonary disease and the progressive stage of pulmonary fibrosis,the activation of pulmonary macrophage autophagy aggravates pulmonary fibrosis,reflecting the dual nature of macrophage autophagy.In allergic asthma,autophagy is activated in lung-resident macrophages but suppressed in infiltrating monocyte-derived macrophages from circulation.The former is closely related to airway stenosis,and the latter aggravates pneumonia disorders.Therefore,identifying the types and progression stages of lung diseases,along with accurately assessing autophagic activity,is crucial for future investigations into the relationship between macrophage autophagy and disease pathogenesis,thereby facilitating the development of therapeutic strategies in the future.
8.Genetic characteristics of influenza A H3N2 virusin Ma'anshan City in 2022 - 2024
Rong WANG ; Zikun YANG ; Zhibin SHEN ; Chen YANG ; Xiaofang ZHU ; Liangliang JIANG ; Ying HONG
Journal of Public Health and Preventive Medicine 2026;37(3):34-38
Objective To analyze the genetic characteristics and variations of influenza A (H3N2) viruses in Ma'anshan from 2022 to 2024, and to provide a scientific basis for local influenza prevention and control. Methods From April 2022 to March 2024, influenza-like illness (ILI) specimens were collected from three national influenza surveillance sentinel hospitals in Ma’anshan. Samples positive for influenza by real-time PCR were subjected to virus culture and identification. A total of 40 representative A/H3N2 strains with hemagglutination titers ≥8 were selected for whole-genome sequencing. Genetic evolution, homology, amino acid variations, and glycosylation sites were analyzed. Results All H3N2 representative strains from the 2022–2023 influenza season belonged to clade 3C.2a1b.2a.1a.1, while those from the 2023–2024 season fell into clade 3C.2a1b.2a.2a.3a.1. The nucleotide and amino acid sequence similarities of HA and NA between the 40 representative strains and the vaccine strain A/Darwin/6/2021 were all above 97.35%. Compared with the vaccine strain, amino acid mutations were identified in antigenic sites A, B, C, and E, as well as in receptor-binding sites of the HA protein. An I222V substitution was detected in the NA protein. The HA protein contained four additional glycosylation sites compared to the vaccine strain, while the glycosylation pattern of the NA protein remained consistent. Conclusion No antigenic drift was observed in the influenza A/H3N2 viruses in Ma'anshan City from 2022 to 2024, but genetic changes such as branching variations, key amino acid substitutions, and an increase in HA glycosylation sites were observed. These findings underscore the importance of sustained molecular surveillance of local influenza viruses.
9.Effect of Acupuncture at Neiguan (PC6) on Improving Autism by Promoting Myelination Through The METTL14/m⁶A/PTEN Axis Based on “Xuanfu-Suiqiao” Theory
Wei-Li DANG ; Lü-Yuan LIANG ; Yu-Xin LI ; Zhi-Yao LI ; Sai-Dan LIU ; Jia-Lei CAO ; Rong-Ze MA ; Yun-Kai WANG ; Xiao-Qing YANG ; Bing-Qi WEI ; Bing-Xiang MA
Progress in Biochemistry and Biophysics 2026;53(5):1165-1177
ObjectiveTo clarify whether METTL14 mediates the core role of acupuncture at Neiguan (PC6) in promoting myelination and improving behavior in young autistic rats through gene intervention technology. MethodsThe ASD model was established by intraperitoneal injection of valproic acid (VPA) in pregnant rats. Male offspring were intracerebroventricularly injected with adenovirus-packaged METTL14 shRNA (sh-METTL14) or its control (sh-NC) on postnatal day 1, with a model group set as well. Subsequently, the juvenile rats were divided into model group, acupuncture group, acupuncture+sh-NC group, and acupuncture+sh-METTL14 group. The acupuncture group received acupuncture at Neiguan (PC6) from postnatal day 7, once daily for 21 consecutive days. Neurobehavioral changes were evaluated by behavioral tests; METTL14 knockdown efficiency and the expression of METTL14, METTL3, and PTEN were detected by quantitative real-time PCR (qRT-PCR) and Western blot (WB); PTEN m6A levels were measured by RNA immunoprecipitation-qPCR (RIP-qPCR); myelin ultrastructure, expression of myelin basic protein (MBP) and neurofascin 155 (NF155), and dendritic spine density were observed using transmission electron microscopy (TEM), enzyme-linked immunosorbent assay (ELISA), immunofluorescence, qRT-PCR, and primary neuron culture. ResultsBehaviorally, knockdown of METTL14 significantly counteracted the beneficial effects of acupuncture in improving self-grooming, open field exploration, three-chamber social interaction, and Morris water maze learning and memory (P<0.05, P<0.01). Compared with the acupuncture+sh-NC group, the acupuncture+sh-METTL14 group showed significantly decreased mRNA and protein expression of hippocampal METTL14 (P<0.01), and the upregulating effects of acupuncture on METTL3 and PTEN expression were reversed (P<0.01). Meanwhile, knockdown of METTL14 significantly inhibited the acupuncture-induced increase in PTEN m6A levels (P<0.01). Morphologically, knockdown of METTL14 attenuated the improvement of myelin structure by acupuncture, reversed the downregulation of MBP and upregulation of NF155 induced by acupuncture, and blocked the increase in dendritic spine density (P<0.05, P<0.01). ConclusionMETTL14 is a key molecule mediating the therapeutic effect of acupuncture at Neiguan. Acupuncture at Neiguan upregulates METTL14, thereby enhancing m6A methylation modification of PTEN mRNA to stabilize its expression, ultimately promoting myelin development and improving behavioral symptoms in ASD juvenile rats. This preliminarily reveals the modern biological connotation of “opening Xuanfu and dredging myelin”.
10.Effects of SPBC1604.04 Gene Deletion on Mitotic Cell Dynamics in Schizosaccharomyces pombe
Jia-Ni XU ; Jia-Yi HE ; Lang-Lin ZHENG ; Shu-Rong HE ; Shuai MA ; Xiang DING ; Yi-Ling HOU
Progress in Biochemistry and Biophysics 2026;53(5):1471-1484
ObjectiveMitochondria are not only the central organelles responsible for cellular energy metabolism but also play essential roles in regulating cell cycle progression and cytoskeletal dynamics. In recent years, accumulating evidence has demonstrated that mitochondrial homeostasis is closely associated with mitotic progression and cytokinesis. Schizosaccharomyces pombe serves as a classical and well-established model organism. Because its cell cycle regulatory mechanisms are highly conserved throughout evolution, its genetic background is clearly defined, and experimental manipulation is efficient and convenient, it has been extensively applied in studies of cell growth, division, and reproductive mechanisms. The SPBC1604.04 gene encodes a previously uncharacterized mitochondrial carrier protein in Schizosaccharomyces pombe. This gene is located on chromosome II and spans 1 018 base pairs in length. It encodes a protein consisting of 238 amino acids with a predicted molecular mass of approximately 31.03 ku. Bioinformatic analysis predicts that this protein is responsible for the transport of thiamine pyrophosphate (TPP) into mitochondria. However, the effects of SPBC1604.04 gene deletion on mitotic cell dynamics under different temperature conditions have not been fully elucidated. MethodsThe SPBC1604.04 deletion strain of Schizosaccharomyces pombe was used as the experimental model. Fluorescent protein markers were constructed in the deletion background to label mitochondria, microtubules, actin, myosin, the nuclear envelope, and chromosomes. Live-cell imaging was performed using a TCS-SP8 laser scanning confocal microscope under normal temperature conditions (25℃) and heat stress conditions (37℃). Time-lapse microscopy was applied to dynamically monitor mitochondrial morphology and distribution, spindle assembly and elongation, chromosome segregation, as well as the formation and constriction of the actomyosin ring during cytokinesis. ImageJ software was used for quantitative measurements, including microtubule length during mitosis, spindle length at different mitotic stages, mitochondrial fluorescence intensity as an indicator of mitochondrial content, actomyosin ring length, nuclear envelope area, and chromosome segregation timing. Statistical analyses were conducted to compare phenotypic differences between the wild-type and SPBC1604.04 deletion strains at both temperature conditions. Through these analyses, we systematically investigated the impact of SPBC1604.04 deletion on mitotic cell dynamics in fission yeast under both normal physiological conditions and temperature stress. ResultsAt 25℃, compared with wild-type cells, the SPBC1604.04Δ strain exhibited a pronounced tendency toward mitochondrial fragmentation, accompanied by abnormal mitochondrial content and a significant reduction in mitochondrial fluorescence intensity. These observations suggest impaired mitochondrial homeostasis under normal growth conditions. In addition, the constriction time of actomyosin ring during cytokinesis was markedly prolonged, indicating that deletion of SPBC1604.04 affects the dynamics of the contractile machinery. However, no obvious defects were observed in spindle assembly, spindle elongation, or chromosome segregation. Under heat stress at 37℃, mitochondrial morphology in the SPBC1604.04Δ strain showed a tendency to recover toward a continuous tubular network structure. Mitochondrial content was restored, fluorescence intensity increased, and the constriction time of the actomyosin ring returned to levels comparable to those of wild-type cells. These results indicate that the mitotic defects observed at normal temperature are partially or fully alleviated under heat stress conditions. ConclusionThis study demonstrates that deletion of the SPBC1604.04 gene leads to abnormal mitochondrial content in Schizosaccharomyces pombe. The mitochondrial carrier protein SPBC1604.04 participates in regulating actomyosin ring constriction during mitosis but does not appear to be directly involved in the regulation of spindle dynamics or chromosome segregation. Our findings provide key experimental evidence for understanding the functional link between the SPBC1604.04 gene, mitochondrial homeostasis, and mitotic regulation.


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