IGF2BP3 regulates the expression of RRM2 and promotes the progression of rheumatoid arthritis via RRM2/Akt/MMP-9 pathway.

BACKGROUND: Rheumatoid arthritis (RA) is a common inflammatory and autoimmune disease. Ribonucleotide Reductase Regulatory Subunit M2 (RRM2) is a crucial and a rate-limiting enzyme responsible for deoxynucleotide triphosphate(dNTP) production. We have found a high expression level of RRM2 in patients with RA, but the molecular mechanism of its action remains unclear. METHODS: We analyzed the expression of hub genes in RA using GSE77298 datasets downloaded from Gene Expression Omnibus database. RRM2 and insulin-like growth factor-2 messenger ribonucleic acid (mRNA)-binding protein 3 (IGF2BP3) gene knockdown was achieved by infection with lentiviruses. The expression of RRM2, IGF2BP3, matrix metalloproteinase (MMP)-1, and MMP-9 were detected via western blotting assay. Cell viability was detected via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. MeRIP-qRT-PCR was performed to test the interaction of IGF2BP3 and RRM2 mRNA via m6A modification. Cell proliferation was determined by clone formation assay. Migration and invasion assays were performed using transwell Boyden chamber. RESULTS: RRM2 and IGF2BP3 were highly expressed in clinical specimens and tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1ß-stimulated synovial cells. RRM2 and IGF2BP3 knockdown inhibited the proliferation, migration, and invasion of MH7A cells. The inhibitory effects of IGF2BP3 knockdown were effectively reversed by simultaneously overexpressing RRM2 in MH7A cells. By analyzing N6-methyladenosine (m6A)2Target database, five m6A regulatory target binding sites for IGF2BP3 were identified in RRM2 mRNA, suggesting a direct relationship between IGF2BP3 and RRM2 mRNA. Additionally, in RRM2 small hairpin (sh)RNA lentivirus-infected cells, the levels of phosphorylated Akt and MMP-9 were significantly decreased compared with control shRNA lentivirus-infected cells. CONCLUSION: The present study demonstrated that RRM2 promoted the Akt phosphorylation leading to high expression of MMP-9 to promote the migration and invasive capacities of MH7A cells. Overall, IGF2BP promotes the expression of RRM2, and regulates the migration and invasion of MH7A cells via Akt/MMP-9 pathway to promote RA progression.

Revision total hip arthroplasty using a fluted, tapered, modular stem follow-up method for a mean of three years: A preliminary study.

Objective: This study aimed to evaluate the results and complications related to revision total hip arthroplasty within a short-to-medium follow up period. Methods: From January 2016 to January 2020, we reviewed 31 prosthetic hip arthroplasty stem revisions using a fluted, tapered modular stem with distal fixation. The median age of the patients was 74.55-79 years. The survival rate was 100%, and there were no re-revisions. The Harris hip score improved from an average of 36.5 ± 7.8 before surgery to 81.8 ± 6.2 at the final follow-up. Results: The average final follow-up was 36 (24-60) months. During this time, there was no periprosthetic infection, no prosthesis loosening or breakage, and no sciatic nerve injury. Complications included four (12.9%) intraoperative fractures and eight (25.8%) dislocations that had no stem fractures. The postoperative limb was lengthened by 17.8 ± 9.8 mm. In most cases, bone regeneration was an early and important finding. Three cases underwent extended trochanteric osteotomy, and bone healing was achieved by the final follow-up. Conclusion: The modular tapered stem reviewed in this study was very versatile, could be used in most femoral revision cases, and allowed for rapid bone reconstruction. However, a long-term follow-up study is needed to confirm these results.

PROSER2 is a poor prognostic biomarker for patients with osteosarcoma and promotes proliferation, migration and invasion of osteosarcoma cells.

Proline- and serine-rich 2 (PROSER2) is encoded by the 47th open reading frame on human chromosome 10. Bioinformatic analysis has shown PROSER2 was significantly correlated with prognostic outcome of osteosarcoma patients. Its role in the progression and metastasis of human osteosarcoma has not been elucidated until now. Bioinformatics analysis was performed on 101 patients with osteosarcoma from The Cancer Genome Atlas database. High levels of PROSER2 were associated with a poor prognosis in patients with osteosarcoma. PROSER2 expression was significantly upregulated in clinical specimens from patients with osteosarcoma and osteosarcoma cell lines. MTT assay was performed to test the cell viability and Transwell assay was used to test the migration and invasion of MG63 cells. PROSER2 knockdown inhibited the viability, migration and invasion of MG63 cells. Gene Set Enrichment Analysis and Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analysis showed that the differentially expressed genes were primarily involved in 'calcium signaling pathway' and 'Wnt signaling' in patients with osteosarcoma and high PROSER2 expression. Western blotting analysis revealed that PROSER2 regulated migration and invasion of osteosarcoma via the Wnt/nuclear factor of activated T-cells (NFAT)c1 signaling pathway. In conclusion, PROSER2 promoted the proliferation, migration and invasion of osteosarcoma cells via the Wnt/Ca2+/NFATc1 signaling pathway by increasing nuclear localization of NFATc1.

CUL3 E3 ligases in plant development and environmental response.

Thirty years of research have revealed the fundamental role of the ubiquitin-proteasome system in diverse aspects of cellular regulation in eukaryotes. The ubiquitin-protein ligases or E3s are central to the ubiquitin-proteasome system since they determine the specificity of ubiquitylation. The cullin-RING ligases (CRLs) constitute one large class of E3s that can be subdivided based on the cullin isoform and the substrate adapter. SCF complexes, composed of CUL1 and the SKP1/F-box protein substrate adapter, are perhaps the best characterized in plants. More recently, accumulating evidence has demonstrated the essential roles of CRL3 E3s, consisting of a CUL3 protein and a BTB/POZ substrate adaptor. In this Review, we describe the variety of CRL3s functioning in plants and the wide range of processes that they regulate. Furthermore, we illustrate how different classes of E3s may cooperate to regulate specific pathways or processes.

Correlation of serum PTH level and fracture healing speed in elderly patients with hip fracture.

PURPOSE: To access serum parathyroid hormone (PTH) level in elderly patients with hip fracture in relation to fracture healing outcomes. METHODS: This study included 90 elderly male patients with hip fracture and they were defined as the hip fracture group, and they were divided into healing effective group and delayed healing group by final fracture healing outcomes, 45 cases in each group; another 45 male patients older than 70 years without established osteoporosis and hip fracture were included as the control group. The levels of serum PTH level were examined in each group. RESULTS: Serum PTH level was significantly higher in healing effective group patients at the 7 days and 14 days after fracture than the delayed healing patients. CONCLUSIONS: Our results show that serum PTH level may be an effective indicator of hip fracture delayed healing risk in the elderly.

The lysine catabolite saccharopine impairs development by disrupting mitochondrial homeostasis.

Amino acid catabolism is frequently executed in mitochondria; however, it is largely unknown how aberrant amino acid metabolism affects mitochondria. Here we report the requirement for mitochondrial saccharopine degradation in mitochondrial homeostasis and animal development. In Caenorhbditis elegans, mutations in the saccharopine dehydrogenase (SDH) domain of the bi-functional enzyme α-aminoadipic semialdehyde synthase AASS-1 greatly elevate the lysine catabolic intermediate saccharopine, which causes mitochondrial damage by disrupting mitochondrial dynamics, leading to reduced adult animal growth. In mice, failure of mitochondrial saccharopine oxidation causes lethal mitochondrial damage in the liver, leading to postnatal developmental retardation and death. Importantly, genetic inactivation of genes that raise the mitochondrial saccharopine precursors lysine and α-ketoglutarate strongly suppresses SDH mutation-induced saccharopine accumulation and mitochondrial abnormalities in C. elegans Thus, adequate saccharopine catabolism is essential for mitochondrial homeostasis. Our study provides mechanistic and therapeutic insights for understanding and treating hyperlysinemia II (saccharopinuria), an aminoacidopathy with severe developmental defects.

Noncatalytic chalcone isomerase-fold proteins in Humulus lupulus are auxiliary components in prenylated flavonoid biosynthesis.

Xanthohumol (XN) and demethylxanthohumol (DMX) are specialized prenylated chalconoids with multiple pharmaceutical applications that accumulate to high levels in the glandular trichomes of hops (Humulus lupulus L.). Although all structural enzymes in the XN pathway have been functionally identified, biochemical mechanisms underlying highly efficient production of XN have not been fully resolved. In this study, we characterized two noncatalytic chalcone isomerase (CHI)-like proteins (designated as HlCHIL1 and HlCHIL2) using engineered yeast harboring all genes required for DMX production. HlCHIL2 increased DMX production by 2.3-fold, whereas HlCHIL1 significantly decreased DMX production by 30%. We show that CHIL2 is part of an active DMX biosynthetic metabolon in hop glandular trichomes that encompasses a chalcone synthase (CHS) and a membrane-bound prenyltransferase, and that type IV CHI-fold proteins of representative land plants contain conserved function to bind with CHS and enhance its activity. Binding assays and structural docking uncover a function of HlCHIL1 to bind DMX and naringenin chalcone to stabilize the ring-open configuration of these chalconoids. This study reveals the role of two HlCHILs in DMX biosynthesis in hops, and provides insight into their evolutionary development from the ancestral fatty acid-binding CHI-fold proteins to specialized auxiliary proteins supporting flavonoid biosynthesis in plants.

A heteromeric membrane-bound prenyltransferase complex from hop catalyzes three sequential aromatic prenylations in the bitter acid pathway.

Bitter acids (α and ß types) account for more than 30% of the fresh weight of hop (Humulus lupulus) glandular trichomes and are well known for their contribution to the bitter taste of beer. These multiprenylated chemicals also show diverse biological activities, some of which have potential benefits to human health. The bitter acid biosynthetic pathway has been investigated extensively, and the genes for the early steps of bitter acid synthesis have been cloned and functionally characterized. However, little is known about the enzyme(s) that catalyze three sequential prenylation steps in the ß-bitter acid pathway. Here, we employed a yeast (Saccharomyces cerevisiae) system for the functional identification of aromatic prenyltransferase (PT) genes. Two PT genes (HlPT1L and HlPT2) obtained from a hop trichome-specific complementary DNA library were functionally characterized using this yeast system. Coexpression of codon-optimized PT1L and PT2 in yeast, together with upstream genes, led to the production of bitter acids, but no bitter acids were detected when either of the PT genes was expressed by itself. Stepwise mutation of the aspartate-rich motifs in PT1L and PT2 further revealed the prenylation sequence of these two enzymes in ß-bitter acid biosynthesis: PT1L catalyzed only the first prenylation step, and PT2 catalyzed the two subsequent prenylation steps. A metabolon formed through interactions between PT1L and PT2 was demonstrated using a yeast two-hybrid system, reciprocal coimmunoprecipitation, and in vitro biochemical assays. These results provide direct evidence of the involvement of a functional metabolon of membrane-bound prenyltransferases in bitter acid biosynthesis in hop.

[Methods of offside reconstruction in total hip arthroplasty for severe osteoarthritis].

OBJECTIVE: To analyze the methods of offside reconstruction in total hip arthroplasty (THA) for severe osteoarthritis. METHODS: Between July 2009 and June 2011, 18 cases (18 hips) of severe osteoarthritis of the hip were treated by THA, including 14 males and 4 females with a mean age of 55.4 years (range; 47-72 years). The disease duration was 11-74 months (mean, 33.6 months). The left hip was involved in 11 cases and the right hip in 7 cases. The hip Harris score was 34.6 ± 5.3. The lower limb discrepency was observed in 15 cases. Thomas sign, Patrick sign, and Trendelenburg sign were positive in all cases. All patients received THA; during operation, standard femoral neck osteotomy was performed and the correct rotation center was chosen to reconstruct offside. RESULTS: All the incisions healed primarily. Common peroneal nerve injury occurred in 1 case and was cured after symptomatic treatment for 3 months, and the other patients had no complication. The mean follow-up period was 43.5 months (range, 30-53 months). All patients achieved pain relief, and returned to normal gait. The X-ray films showed no dislocation of the hip or prosthetic loosening. Lower limb discrepency was observed in 6 cases. The mean offside difference between normal and ipsilateral side was 0.4 mm (range, 0.1-0.7 mm). At last follow-up, the hip Harris score was 83.0 ± 7.1, showing significant difference when compared with preoperative score (t = -22.96, P = 0.01); the hip range of motion was significantly increased when compared with preoperative one (P < 0.05). CONCLUSION: The offside reconstruction can accurately be carried out by making precise template and vernier caliper measurement, selecting suitable prosthesis preoperatively, maintaining the proper femoral calcar length, adjusting the length of the neck and neck-shaft angle, releasing the soft tissue reasonably during THA for severe osteoarthritis, and the short-term effectiveness is satisfactory.