Immunohistochemical localization of Phosphoglycerate mutase in capillary endothelium of the brain and periphery

Comparative proteomics reveals Cryptosporidium parvum manipulation of the host cell molecular expression and immune response

Cryptosporidium is a life-threating protozoan parasite belonging to the phylum Apicomplexa, which mainly causes gastroenteritis in a variety of vertebrate hosts. Currently, there is a re-emergence of Cryptosporidium infection; however, no fully effective drug or vaccine is available to treat Cryptosporidiosis. In the present study, to better understand the detailed interaction between the host and Cryptosporidium parvum, a large-scale label-free proteomics study was conducted to characterize the changes to the proteome induced by C. parvum infection. Among 4406 proteins identified, 121 proteins were identified as differentially abundant (> 1.5-fold cutoff, P < 0.05) in C. parvum infected HCT-8 cells compared with uninfected cells. Among them, 67 proteins were upregulated, and 54 proteins were downregulated at 36 h post infection. Analysis of the differentially abundant proteins revealed an interferon-centered immune response of the host cells against C. parvum infection and extensive inhibition of metabolism-related enzymes in the host cells caused by infection. Several proteins were further verified using quantitative real-time reverse transcription polymerase chain reaction and western blotting. This systematic analysis of the proteomics of C. parvum-infected HCT-8 cells identified a wide range of functional proteins that participate in host anti-parasite immunity or act as potential targets during infection, providing new insights into the molecular mechanism of C. parvum infection.

Cryptosporidium parvum is an emerging zoonotic pathogen transmitted via the fecal–oral route, and is considered a leading cause of moderate-to-severe diarrheal disease in young children in resource limited areas. After infection, C. parvum parasitizes intestinal epithelial cells and evokes an inflammatory immune response, leading to severe damage of the intestinal mucosa. The infection can be lethal to immunosuppressed individuals. However, no fully effective drug or vaccine is available for cryptosporidiosis, and the pathogenesis and immune mechanisms during C. parvum infection are obscure. Thus, an in-depth understanding of host-parasite interaction is needed. Hence, we established a C. parvum-infected HCT-8 cell model and performed comparative quantitative proteomic analyses to profile global host-parasite interactions and determine the molecular mechanisms that are activated during infection, aiming to offer new insights into the treatment of Cryptosporidium.

Proteomic analysis of TGFβ-induced A549 secretome identifies putative regulators of epithelial-mesenchymal transition

Imparting epithelial to mesenchymal transition (EMT) during cellular transformation, a major driving force behind tumor progression, is one of the notorious oncogenic activities of transforming growth factor β (TGFβ); however, the secretary factors released during TGFβ-induced EMT that may have role in potentiating EMT and tumor progression are poorly known. This study was undertaken to identify such secreted protein factors from TGFβ-induced A549 cells cultured in serum-free chemically defined medium (Freestyle^TM ) using Matrix Assisted Laser Desorption Ionization-Time of flight/Time of flight (MALDI-TOF/TOF) mass spectrometry. We identified some of the potential factors such as ESR, ANXA2, ALDH1A, TGFβ-induced protein ig-h3, and PAI-1 that were not only secreted but some were also elevated in TGFβ-induced A549 cells. Interestingly, these factors are widely reported to play crucial role in EMT induction and progression, which not only validates our findings but also opens avenues for further investigation, if upon secretion they act exogenously through certain receptors to potentiate cellular signaling involved in EMT induction and tumor progression.

Phosphoglycerate Mutase 1: Its Glycolytic and Non-Glycolytic Roles in Tumor Malignant Behaviors and Potential Therapeutic Significance

Phosphoglycerate mutase 1 (PGAM1) is an important enzyme that catalyzes the reversible conversion of 3-phosphoglycerate and 2-phosphoglycerate during the process of glycolysis. Increasing evidence suggests that PGAM1 is widely overexpressed in various cancer tissues and plays a significant role in promoting cancer progression and metastasis. Although PGAM1 is a potential target in cancer therapy, the specific mechanisms of action remain unknown. This review introduces the basic structure and functions of PGAM1 and its family members and summarizes recent advances in the role of PGAM1 and various inhibitors of cancer cell proliferation and metastasis from a glycolytic and non-glycolytic perspective. Recent studies have highlighted a correlation between PGAM1 and clinical features and prognosis of cancer as well as the development of target drugs for PGAM1. The integrated information in this review will help better understand the specific roles of PGAM1 in cancer progression. Furthermore, the information highlights the non-glycolytic functions of PGAM1 in tumor metastasis, providing an innovative basis and direction for clinical drug research.

PGAM1 knockdown is associated with busulfan‑induced hypospermatogenesis and spermatogenic cell apoptosis

Phosphoglycerate mutase 1 (PGAM1) is reported to be involved in spermatogenic dysfunction. However, the association between PGAM1 and busulfan-induced hypospermatogenesis and spermatogenic cell apoptosis remains unclear. The aim of the current study was to investigate the association between PGAM1 expression and busulfan-induced hypospermatogenesis, and the effect of PGAM1 expression on spermatogenic cell apoptosis. PGAM1 expression was detected in mouse models of busulfan-induced hypospermatogenesis by western blotting, reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. Then, spermatogenic cell apoptosis in mouse models of busulfan-induced hypospermatogenesis was assessed by TUNEL assay. The effect and potential mechanism of PGAM1 downregulation on spermatogenic cells were further investigated. The results indicated that PGAM1 expression was significantly downregulated in the mouse models of busulfan-induced hypospermatogenesis, compared with those with normal spermatogenesis (P<0.05). Furthermore, the TUNEL assay revealed that the apoptosis of spermatogenic cells was accelerated in the mouse model of busulfan-induced hypospermatogenesis. In addition, PGAM1 knockdown promoted the apoptosis of spermatogenic cells in vitro, which was associated with the P53/Caspase 3/Caspase 6/Caspase 9 signaling pathway. In conclusion, these data indicate that PGAM1 knockdown is associated with busulfan-induced hypospermatogenesis and contributes to spermatogenic cell apoptosis by regulating the P53/Caspase 3/Caspase 6/Caspase 9 signaling pathway.

Phosphoglycerate Mutase 1 Promotes Cell Proliferation and Neuroblast Differentiation in the Dentate Gyrus by Facilitating the Phosphorylation of cAMP Response Element-Binding Protein

In a previous study, we observed a significant increase in phosphoglycerate mutase 1 (PGAM1) levels after pyridoxine treatment. In the present study, we investigated the effects of PGAM1 on novel object recognition, cell proliferation, and neuroblast differentiation in the dentate gyrus. We generated a Tat-PGAM1 fusion protein to cross the blood-brain barrier and neuronal plasma membrane. We administered the Tat peptide, control-PGAM1, or Tat-PGAM1 fusion protein to 8-week-old mice once a day for 3 weeks and tested novel object recognition memory. The mice were then euthanized to conduct western blot analysis for polyhistidine expression and immunohistochemical analysis for Ki67, doublecortin, and phosphorylated cAMP response element-binding protein. Mice treated with Tat peptide showed similar exploration times for familiar and new objects and the discrimination index was significantly lower in this group than in the control group. Tat-PGAM1 moderately increased the exploration time of new objects when compared to familiar objects, while the discrimination index was significantly higher in the Tat-PGAM1-treated group, but not in the control-PGAM1-treated group, when compared with the control group. Higher PGAM1 protein expression was observed in the hippocampus of Tat-PGAM1-treated mice when compared with the hippocampi of control, Tat peptide-, and control-PGAM1-treated mice, using western blot analysis. In addition, the numbers of proliferating cells and differentiated neuroblasts were significantly lower in the Tat peptide-treated group than in the control group. In contrast, the numbers of proliferating cells and differentiated neuroblasts in the dentate gyrus were higher in the Tat-PGAM1-treated group than in the control group. Administration of Tat-PGAM1 significantly facilitated the phosphorylation of cAMP response element-binding protein in the dentate gyrus. Administration of control-PGAM1 did not show any significant effects on novel object recognition, cell proliferation, and neuroblast differentiation in the dentate gyrus. These results suggest that PGAM1 plays a role in cell proliferation and neuroblast differentiation in the dentate gyrus via the phosphorylation of cAMP response element-binding protein in the hippocampus.

PGAM1 is Involved in Spermatogenic Dysfunction and Affects Cell Proliferation, Apoptosis, and Migration

OBJECTIVE

To investigate the correlation between PGAM1 and spermatogenic dysfunction and to evaluate the effect of expression of PGAM1 on the function of germ cells.

METHODS

Expression of PGAM1 was detected in 40 cases of infertile males with definite pathological diagnosis and 12 cases of mouse models with spermatogenic dysfunction by immunohistochemistry. Then, cell proliferation, apoptosis, and migration were evaluated when expression of PGAM1 was knocked down by a specific small interfering RNA in GC1 and TM4 cells.

RESULTS

The positive rates of PGAM1 in patients with normal spermatogenesis, mild hypospermatogenesis, severe hypospermatogenesis, and Sertoli cell-only syndrome were 90%, 80%, 10%, 100%, respectively, and the difference was significant (P < .001). Meanwhile, expression of PGAM1 was found to be significantly decreased in mouse models with spermatogenic dysfunction. Moreover, when expression of PGAM1 was knocked down in GC1 cells, the proliferation and migration were significantly inhibited, but the rate of apoptosis was significantly increased. Furthermore, PGAM1 downregulation in TM4 cells significantly inhibited proliferation and promoted apoptosis but didn't affect migration.

CONCLUSION

PGAM1 correlates with spermatogenic distinction and affects the function of cell proliferation, apoptosis and migration.