Real-world study for identifying the predictive factors of surgical intervention and the value of magnetic resonance imaging in patients with low back pain

BACKGROUND

Low back pain (LBP) is a prevalent disease and can be disabling. Currently, many patients with LBP with or without radiculopathy commonly undergo magnetic resonance imaging (MRI) for diagnosis and therapeutic assessment, yet the final intervention is mainly centered around nonoperative treatment. This study's aim was to identify the predictive factors of surgical treatment and the value of MRI in patients with LBP with or without radiculopathy.

METHODS

The study included a training cohort that consisted of 461 patients with MRI from January 2014 to December 2018. Demographic characteristics and MRI findings were collected from our medical records. We developed and validated 2 nomograms to predict the possibility of receiving surgical treatment in LBP patients, based on multivariable logistic regression analysis. The performance of the 2 nomograms was assessed in terms of their calibration, discrimination, and clinical usefulness. An independent validation cohort containing 163 patients was comparatively analyzed.

RESULTS

The baseline model incorporated 6 clinicopathological variables, while the MRI model consisted of 9 variables including several MRI findings. Internal validation revealed the good performance of the 2 nomograms in discrimination and calibration, with a concordance index (C-index) of 0.799 (95% CI: 0.743-0.855) for the baseline model and 0.834 (95% CI: 0.783-0.884) for the MRI model, which showed that the addition of MRI findings to the nomogram failed to achieve better prognostic value (Z statistic =-1.509; P=0.131). Application of the 2 models in the validation cohort also showed good discrimination (baseline model: C-index 0.75, 95% CI: 0.671-0.829; MRI model: C-index 0.777, 95% CI: 0.696-0.857) and calibration. No significant predictive benefit was found in the MRI model in the validation cohort (Z statistic =-0.588; P=0.557).

CONCLUSIONS

This study showed that clinical demographic characteristics provide good prognostic value to determine whether LBP patients with or without radiculopathy require surgical treatment. The addition of MRI findings yielded no significantly incremental prognostic value.

Active or Autoclaved Akkermansia muciniphila Relieves TNF-α-Induced Inflammation in Intestinal Epithelial Cells Through Distinct Pathways

Intestinal inflammation is a major threat to the health and growth of young animals such as piglets. As a next-generation probiotics, limited studies have shown that Akkermansia muciniphila could alleviate inflammation of intestinal epithelial cells (IECs). In this study, a TNF-α-induced inflammatory model of IPEC-J2 cells, the intestinal porcine enterocytes, was built to evaluate the effects of active or inactive A. muciniphila on the inflammation of IECs. The viability of IPEC-J2 cells was the highest when treated with active (10⁸ copies/mL) or inactive (10⁹ copies/mL) A. muciniphila for 7.5 h (P < 0.01). Treated with 20 ng/mL of TNF-α and followed by a treatment of A. muciniphila, the mRNA level of proinflammatory cytokines (IL-8, IL-1β, IL-6 and TNF-α) was remarkably reduced (P < 0.05) along with the increased mRNA level of tight junction proteins (ZO-1 and Occludin, P < 0.05). Flow cytometry analysis showed that active or inactive A. muciniphila significantly suppressed the rate of the early and total apoptotic of the inflammatory IPEC-J2 cells (P < 0.05). According to results of transcriptome sequencing, active and inactive A. muciniphila may decline cell apoptosis by down-regulating the expression of key genes in calcium signaling pathway, or up-regulating the expression of key genes in cell cycle signaling pathway. And the bacterium may alleviate the inflammation of IECs by down-regulating the expression of PI3K upstream receptor genes. Our results indicate that A. muciniphila may be a promising NGP targeting intestinal inflammation.

Apigenin Alleviates Intervertebral Disc Degeneration via Restoring Autophagy Flux in Nucleus Pulposus Cells

Oxidative stress–induced apoptosis and senescence of nucleus pulposus (NP) cells play a crucial role in the progression of intervertebral disc degeneration (IVDD). Accumulation of studies has shown that activated autophagy and enhanced autophagic flux can alleviate IVDD. In this study, we explored the effects of apigenin on IVDD in vitro and in vivo. Apigenin was found to inhibit tert-butyl hydroperoxide (TBHP)–induced apoptosis, senescence, and ECM degradation in NP cells. In addition, apigenin treatment can restore the autophagic flux blockage caused by TBHP. Mechanistically, we found that TBHP may induce autophagosome and lysosome fusion interruption and lysosomal dysfunction, while apigenin alleviates these phenomena by promoting the nuclear translocation of TFEB via the AMPK/mTOR signaling pathway. Furthermore, apigenin also exerts a protective effect against the progression of IVDD in the puncture-induced rat model. Taken together, these findings indicate that apigenin protects NP cells against TBHP-induced apoptosis, senescence, and ECM degradation via restoration of autophagic flux in vitro, and it also ameliorates IVDD progression in rats in vivo, demonstrating its potential for serving as an effective therapeutic agent for IVDD.

High energy irradiation effects on silicon photonic passive devices

In this work, the radiation responses of silicon photonic passive devices built in silicon-on-insulator (SOI) technology are investigated through high energy neutron and ⁶⁰Co γ-ray irradiation. The wavelengths of both micro-ring resonators (MRRs) and Mach-Zehnder interferometers (MZIs) exhibit blue shifts after high-energy neutron irradiation to a fluence of 1×10¹² n/cm²; the blue shift is smaller in MZI devices than in MRRs due to different waveguide widths. Devices with SiO₂ upper cladding layer show strong tolerance to irradiation. Neutron irradiation leads to slight changes in the crystal symmetry in the Si cores of the optical devices and accelerated oxidization for devices without SiO₂ cladding. A 2-µm top cladding of SiO₂ layer significantly improves the radiation tolerance of these passive photonic devices.

Integrative transcriptomic and metabolomic data provide insights into gene networks associated with lignification in postharvest Lei bamboo shoots under low temperature

Lei bamboo (Phyllostachys violascens) shoots are delicious food in Asia. Here, the molecular basis of lignification in postharvest Lei bamboo shoots under low temperature (LT) is revealed by transcriptomic and metabolomics analyses for the first time. We identified substantial accumulations of jasmonates (JAs) and major lignin biosynthesis precursors (coumarin, trans-4-coumaric acid, trans-ferulic acid and L-phenylalanine). Transcriptome analysis indicated that some regulatory genes were significantly differentially expressed, and the expression patterns of them were highly consistent with the changes in the key lignin precursors or JA profiles. Co-expression analysis showed that the LT responsive genes PvCRPK-4/-5, PvICE2-1/2, PvDREB2B might form a network module with the lignin (PvC3H-2/3, PvC4H-2/4, PvCAD-1/2/3/4, etc.) or JA biosynthesis genes (PvOPR2, PvJAZ-4 and PvPEX5, etc.), indicating a LT-lignification or LT-JA-lignification regulatory pathway in Lei bamboo shoots. Above all, our findings provide new an insight into the LT-associated lignification in postharvest bamboo shoots.

Itaconate attenuates osteoarthritis by inhibiting STING/NF-κB axis in chondrocytes and promoting M2 polarization in macrophages

Osteoarthritis (OA) is a progressive joint disease characterized by the degradation and destruction of articular cartilage, which is involved with pathological microenvironmental alterations induced by damaged chondrocytes and inflammatory macrophages. However, the current therapies cannot effectively alleviate the progression of OA. Our previous studies have shown that the pathological process of OA progression is accompanied by DNA damage, and inhibition of STING, a key molecule in DNA damage, may become a potential method for the treatment of OA. Itaconate, a metabolite highly expressed in macrophages under inflammatory conditions, has shown a wide range of anti-inflammatory effects, but its effect on OA and its underlying mechanism has not yet been studied. In this study, we found that exogenous supplementation of itaconate can activate Nrf2, and accordingly inhibit the STING-dependent NF-κB pathway, thereby alleviating the inflammation, ECM degeneration and senescence of chondrocytes stimulated by IL-1β. In addition, itaconate can regulate the polarization of RAW264.7 macrophages, further reducing the apoptosis of chondrocytes. In vivo, intra-articular injection of itaconate reduces the degradation of cartilage and inflammation of synovial membrane in the mouse OA model. In conclusion, the present work suggests that exogenous supplementation of itaconate inhibits the inflammation, senescence and ECM degeneration of chondrocytes through the Nrf2/STING/NF-κB axis and regulates the polarization of synovial macrophages, thereby ameliorating the progression of OA, which supports that itaconate as a potential drug for the treatment of OA.

QTL and candidate gene identification of the node of the first fruiting branch (NFFB) by QTL-seq in upland cotton (Gossypium hirsutum L.)

Background

The node of the first fruiting branch (NFFB) is an important precocious trait in cotton. Many studies have been conducted on the localization of quantitative trait loci (QTLs) and genes related to fiber quality and yield, but there has been little attention to traits related to early maturity, especially the NFFB, in cotton.

Results

To identify the QTL associated with the NFFB in cotton, a BC₄F₂ population comprising 278 individual plants was constructed. The parents and two DNA bulks for high and low NFFB were whole genome sequenced, and 243.8 Gb of clean nucleotide data were generated. A total of 449,302 polymorphic SNPs and 135,353 Indels between two bulks were identified for QTL-seq. Seventeen QTLs were detected and localized on 11 chromosomes in the cotton genome, among which two QTLs (qNFFB-Dt2–1 and qNFFB-Dt3–3) were located in hotspots. Two candidate genes (GhAPL and GhHDA5) related to the NFFB were identified using quantitative real-time PCR (qRT-PCR) and virus-induced gene silencing (VIGS) experiments in this study. Both genes exhibited higher expression levels in the early-maturing cotton material RIL182 during flower bud differentiation, and the silencing of GhAPL and GhHDA5 delayed the flowering time and increased the NFFB compared to those of VA plants in cotton.

Conclusions

Our study preliminarily found that GhAPL and GhHDA5 are related to the early maturity in cotton. The findings provide a basis for the further functional verification of candidate genes related to the NFFB and contribute to the study of early maturity in cotton.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08164-2.

Bloch Surface Waves Mediated Micro-Spectroscopy

Micro-spectroscopy is a critical instrument for spectrum analysis in various applications such as chemical and biological analysis, environment detection, and hyperspectral imaging. However, current micro-spectral technique requires bulky and costly spectrometer. In this report, a new type of Bloch surface wave (BSW) based micro-spectrometer is proposed. A single silicon nanoparticle sitting on a dielectric multilayer substrate is used to excite the BSW which acts as a nanoscale unknown source. Taking advantage of the dispersion relations of BSWs, an abundant spectrally related database is formed that is useful for spectrum retrieval applications. Back-focal plane images are used to monitor the change of angular spectrum corresponding to the dispersion relationship of Bloch surface waves. Combined with an iterative algorithm, experimental retrieval of visible-range monochromatic and broadband light spectrums can be obtained. The resolution of the spectrometers can reach 2 nm across a wavelength range of 130 nm. The method in this work is CMOS compatible, enabling spectra retrieval for nanoscale radiators and can also be used to measure and retrieve the microscopic spectrum signal rapidly and timely without conventional scanning monochromator spectrometer.

Homo- and Hetero-Dimers of CAD Enzymes Regulate Lignification and Abiotic Stress Response in Moso Bamboo

Lignin biosynthesis enzymes form complexes for metabolic channelling during lignification and these enzymes also play an essential role in biotic and abiotic stress response. Cinnamyl alcohol dehydrogenase (CAD) is a vital enzyme that catalyses the reduction of aldehydes to alcohols, which is the final step in the lignin biosynthesis pathway. In the present study, we identified 49 CAD enzymes in five Bambusoideae species and analysed their phylogenetic relationships and conserved domains. Expression analysis of Moso bamboo PheCAD genes in several developmental tissues and stages revealed that among the PheCAD genes, PheCAD2 has the highest expression level and is expressed in many tissues and PheCAD1, PheCAD6, PheCAD8 and PheCAD12 were also expressed in most of the tissues studied. Co-expression analysis identified that the PheCAD2 positively correlates with most lignin biosynthesis enzymes, indicating that PheCAD2 might be the key enzyme involved in lignin biosynthesis. Further, more than 35% of the co-expressed genes with PheCADs were involved in biotic or abiotic stress responses. Abiotic stress transcriptomic data (SA, ABA, drought, and salt) analysis identified that PheCAD2, PheCAD3 and PheCAD5 genes were highly upregulated, confirming their involvement in abiotic stress response. Through yeast two-hybrid analysis, we found that PheCAD1, PheCAD2 and PheCAD8 form homo-dimers. Interestingly, BiFC and pull-down experiments identified that these enzymes form both homo- and hetero- dimers. These data suggest that PheCAD genes are involved in abiotic stress response and PheCAD2 might be a key lignin biosynthesis pathway enzyme. Moreover, this is the first report to show that three PheCAD enzymes form complexes and that the formation of PheCAD homo- and hetero- dimers might be tissue specific.

A Comprehensive Study on the Dynamic Change of Thermal Behavior During Lignocellulose Pyrolysis Catalyzed by Plant-Rich Metallic Elements

Evaluating the pyrolysis of lignocellulose via theoretical and computational approaches is of great importance for the efficient utilization of biomass. In this work, the dynamic changes in physicochemical properties of eucalyptus and bamboo during plant-rich metallic element-catalyzed pyrolysis process were investigated, and their thermal decomposition behaviors were explored by kinetic analysis. Results showed that the metal absorption capacity and thermal stability of eucalyptus were better than those of bamboo. The temperatures corresponding to the initial devolatilization and the highest weight loss value of eucalyptus/bamboo decreased in the catalysis order of Mg > Fe > Ca > Cu > K > Na. Fourier-transform infrared (FT-IR) results showed that the thermal stability of ester bond of glucuronoarabinoxylan was higher than that of acetyl groups. The maximum weight loss rate could be observed for samples with the lowest metal-loaded concentration (5%). Moreover, Mg and Fe presented the better catalytic performance for facilitating the lignocellulose pyrolysis in comparison with other investigated metallic elements.

Fibroblast growth factor 21 attenuates iron overload-induced liver injury and fibrosis by inhibiting ferroptosis

Ferroptosis plays a role in several diseases such as iron overload-induced liver diseases. Manipulation of ferroptosis has been explored as a potential therapeutic strategy to treat related diseases. Numerous antioxidants have been identified to control ferroptosis but the cell-autonomous mechanisms responsible for regulating ferroptosis remain elusive. In the present study, we found that iron overload promoted ferroptosis in hepatocytes by excessively inducing HO-1 expression, which contributed to the progression of liver injury and fibrosis, accompanied by the upregulation of the FGF21 protein level in vitro and in vivo. Interestingly, both recombinant FGF21 and Fgf21 overexpression significantly protected against iron overload-induced hepatocytes mitochondria damage, liver injury and fibrosis by inhibiting ferroptosis. In contrast, the loss of FGF21 aggravated iron overload-induced ferroptosis. Notably, FGF21-induced HO-1 inhibition (via the promotion of HO-1 ubiquitination and degradation) and NRF2 activation provide a mechanistic explanation for this phenomenon. Taken together, we identified FGF21 as a novel ferroptosis suppressor. Thus, FGF21 activation may provide an effective strategy for the potential treatment of iron overload-induced ferroptosis-related diseases, such as hereditary haemochromatosis (HH).

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Iron overload robustly induces hepatic FGF21 expression both in vitro and in vivo.

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FGF21 suppresses iron overload-induced hepatocytes ferroptosis.

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Constitutive HO-1 activation contributes to iron overload-induced ferroptosis in hepatocytes.

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FGF21 protects hepatocytes from iron overload-induced ferroptosis by stimulating HO-1 ubiquitination and degradation.

GhLUX1 and GhELF3 Are Two Components of the Circadian Clock That Regulate Flowering Time of Gossypium hirsutum

Photoperiod is an important external factor that regulates flowering time, the core mechanism of which lies in the circadian clock-controlled expression of FLOWERING LOCUS T (FT) and its upstream regulators. However, the roles of the circadian clock in regulating cotton flowering time are largely unknown. In this study, we cloned two circadian clock genes in cotton, GhLUX1 and GhELF3. The physicochemical and structural properties of their putative proteins could satisfy the prerequisites for the interaction between them, which was proved by yeast two-hybrid (Y2H) and Bimolecular Fluorescent Complimentary (BiFC) assays. Phylogenetic analysis of LUXs and ELF3s indicated that the origin of LUXs was earlier than that of ELF3s, but ELF3s were more divergent and might perform more diverse functions. GhLUX1, GhELF3, GhCOL1, and GhFT exhibited rhythmic expression and were differentially expressed in the early flowering and late-flowering cotton varieties under different photoperiod conditions. Both overexpression of GhLUX1 and overexpression of GhELF3 in Arabidopsis delayed flowering probably by changing the oscillation phases and amplitudes of the key genes in the photoperiodic flowering pathway. Both silencing of GhLUX1 and silencing of GhELF3 in cotton increased the expression of GhCOL1 and GhFT and resulted in early flowering. In summary, the circadian clock genes were involved in regulating cotton flowering time and could be the candidate targets for breeding early maturing cotton varieties.

Chitosan oligosaccharide attenuates endoplasmic reticulum stress-associated intestinal apoptosis via the Akt/mTOR pathway

Endoplasmic reticulum stress (ERS) and apoptosis are widely considered as essential factors associated with intestinal disorders, whereas nutritional therapeutic approaches targeting ERS may control disease activity. Thus, we focus on the potential benefit of chitosan oligosaccharide (COS) on repressing ERS and ERS-induced apoptosis. In this study, we used the ERS model with tunicamycin (TM)-induced IPEC-J2 cells in vitro and nutrient deprivation-induced ERS in piglets to evaluate the protective mechanism of COS against ERS and ERS-induced apoptosis. The results showed that cells were characterized by activation of the unfolded protein response (UPR) and increased epithelial apoptosis upon exposure to TM. However, these changes were significantly attenuated by COS and the expressions of Akt and mTORC1 were inhibited. Furthermore, a specific inhibitor of mTOR confirmed the suppression of Akt and reduced the activation of the UPR and apoptosis. In vivo, COS protected against nutrient deprivation-induced ERS in the jejunum of piglets, in which the overexpression of the UPR and apoptosis was rescued. Consistently, COS attenuated nutrient deprivation-induced disruption of intestinal barrier integrity and functional capacity. Together, we provided the first evidence that COS could protect against intestinal apoptosis through alleviating severe ERS, which may be related to the inhibition of the Akt/mTOR signaling pathway.

Non-functional GoFLA19s are responsible for the male sterility caused by hybrid breakdown in cotton (Gossypium spp.)

Hybrid breakdown (HB) functions as a common reproductive barrier and reduces hybrid fitness in many species, including cotton. However, the related genes and the underlying genetic mechanisms of HB in cotton remain unknown. Here, we found that the photosensitive genetic male sterile line CCRI9106 was a hybrid progeny of Gossypium hirsutum and Gossypium barbadense and probably a product of HB. Fine mapping with F₂ s (CCRI9106 × G. hirsutum/G. barbadense lines) identified a pair of male sterility genes GoFLA19s (encoding fasciclin-like arabinogalactan family protein) located on chromosomes A12 and D12. Crucial variations occurring in the fasciclin-like domain and the arabinogalactan protein domain were predicted to cause the non-functionalization of GbFLA19-D and GhFLA19-A. CRISPR/Cas9-mediated knockout assay confirmed the effects of GhFLA19s on male sterility. Sequence alignment analyses showed that variations in GbFLA19-D and GhFLA19-A likely occurred after the formation of allotetraploid cotton species. GoFLA19s are specifically expressed in anthers and contribute to tapetal development, exine assembly, intine formation, and pollen grain maturation. RNA-sequencing and quantitative reverse transcriptase-polymerase chain reaction analyses illustrated that genes related to these biological processes were significantly downregulated in the mutant. Our research on male sterility genes, GoFLA19s, improves the understanding of the molecular characteristics and evolutionary significance of HB in interspecific hybrid breeding.

Comparison of Thalamus and Basal Ganglia Signs Between Multiple Sclerosis and Primary Angiitis of the Central Nervous System: An Exploratory Study

Based on the symptoms, especially those affecting small vessels, it is difficult to distinguish multiple sclerosis (MS) from primary angiitis of the central nervous system (PACNS). Magnetic resonance imaging (MRI) helps understand the characteristics of deep gray matter lesions (DGML) in MS and PACNS. We aimed to compare the MRI characteristics of thalamus and basal ganglia lesions between relapsing-remitting MS and PACNS. In our study, 49 relapsing-remitting MS patients and 16 PACNS with MRI-confirmed thalamus or basal ganglia lesions were enrolled. Among the DGMLs in basal ganglia, putamen had significantly higher (P = 0.037) involvement in PACNS than in MS. More importantly, larger lesion sizes in thalamus helps to distinguish PACNS (12.4 ± 4.3 mm) from MS (7.9 ± 3.7 mm) (P = 0.006). But using lesions in basal ganglia, researchers were unable to differentiate the two disorders. Presently, our study shows that MRI performances of deep gray matter differ between MS and PACNS.

Sinensetin Reduces Osteoarthritis Pathology in the Tert-Butyl Hydroperoxide-Treated Chondrocytes and the Destabilization of the Medial Meniscus Model Mice via the AMPK/mTOR Signaling Pathway

As a common degenerative disease, osteoarthritis (OA) usually causes disability in the elderly and socioeconomic burden. Previous studies have shown that proper autophagy has a protective effect on OA. Sinensetin (Sin) is a methylated flavonoid derived from citrus fruits. Studies have shown that Sin is a good autophagy inducer and has shown excellent therapeutic effects in a variety of diseases; however, its role in the treatment of OA is not fully understood. This study proved the protective effect of Sin on OA through a series of in vivo and in vitro experiments. In vitro experiments have shown that Sin may inhibit chondrocyte apoptosis induced by tert-butyl hydroperoxide (TBHP); at the same time, it might also inhibit the production of MMP13 and promote the production of aggrecan and collagen II. Mechanism studies have shown that Sin promotes chondrocyte autophagy by activating AMPK/mTOR signaling pathway. On the contrary, inhibition of autophagy can partially abolish the protective effect of Sin on TBHP-treated chondrocytes. In vivo experiments show that Sin may protect against DMM-induced OA pathogenesis. These results provide evidence that Sin serves as a potential candidate for the treatment of OA.

Directional imbalance of Bloch surface waves for ultrasensitive displacement metrology

Precise position sensing and nanoscale optical rulers are important in many applications in nanometrology, gravitational wave detection and quantum technologies. Several implementations of such nanoscale displacement sensors have been recently developed based on interferometers, nanoantennas, optical field singularities and optical skyrmions. Here, we propose a method for ultrasensitive displacement measurements based on the directional imbalance of the excitation of Bloch surface waves by an asymmetric double slit, which have low propagation loss and provide high detected intensity. The directionality of excitation changes dramatically with a sub-nanometric displacement of the illuminating Gaussian beam across the slit and can be used for displacement and refractive index metrology. We demonstrate a theoretical intensity ratio of the BSW excitation in opposite directions exceeding 890, which provides a displacement sensitivity of up to 2.888 nm^-1 with a resolution below 0.5 nm over a 100 nm linearity range. Experimentally, a directional intensity ratio more than 90 has been achieved, with a displacement sensitivity of 0.122 nm^-1 over a 300 nm linearity range, resulting in a resolution below 8 nm for a 600 nm illumination wavelength. The proposed facile configuration may have potential applications in nanometrology and super-resolution microscopy.

β-Hydroxyisovalerylshikonin inhibits IL-1β-induced chondrocyte inflammation via Nrf2 and retards osteoarthritis in mice

Osteoarthritis is a chronic degenerative disease characterized by cartilage destruction. It is the fourth most disabling disease worldwide and is currently incurable. Inflammation and extracellular matrix (ECM) degradation are considered to be substantial reasons for accelerating the progression of OA. β-Hydroxyisoamylshikonin (β-HIVS) is a natural naphthoquinone compound with anti-inflammatory and antioxidant activity. However, the effect of β-HIVS on OA is still unclear. In this study, we found that β-HIVS can down-regulate the expression of NO, PEG2, IL-6, TNF-α, COX-2, and iNOS, suggesting its anti-inflammatory effects in chondrocytes; we also found that β-HIVS may down-regulate the expression of ADAMTS5 and MMP13 and up-regulate the expression of aggrecan and collagen II to inhibit the degradation of ECM. Mechanistically, β-HIVS inhibited the NFκB pathway by activating the Nrf2/HO-1 axis, thereby exerting its anti-inflammatory and inhibitory effects on ECM degradation. In vivo experiments also proved the therapeutic effects of β-HIVS on OA in mice, and Nrf2 is the target of β-HIVS. These findings indicate that β-HIVS may become a new drug for the treatment of OA.

Genome-Wide Identification of the Early Flowering 4 (ELF4) Gene Family in Cotton and Silent GhELF4-1 and GhEFL3-6 Decreased Cotton Stress Resistance

The early flowering 4 (ELF4) family members play multiple roles in the physiological development of plants. ELF4s participated in the plant biological clock's regulation process, photoperiod, hypocotyl elongation, and flowering time. However, the function in the ELF4s gene is barely known. In this study, 11, 12, 21, and 22 ELF4 genes were identified from the genomes of Gossypium arboreum, Gossypium raimondii, Gossypium hirsutum, and Gossypium barbadense, respectively. There ELF4s genes were classified into four subfamilies, and members from the same subfamily show relatively conservative gene structures. The results of gene chromosome location and gene duplication revealed that segmental duplication promotes gene expansion, and the Ka/Ks indicated that the ELF4 gene family has undergone purification selection during long-term evolution. Spatio-temporal expression patterns and qRT-PCR showed that GhELF4 genes were mainly related to flower, leaf, and fiber development. Cis-acting elements analysis and qRT-PCR showed that GhELF4 genes might be involved in the regulation of abscisic acid (ABA) or light pathways. Silencing of GhELF4-1 and GhEFL3-6 significantly affected the height of cotton seedlings and reduced the resistance of cotton. The identification and functional analysis of ELF4 genes in upland cotton provide more candidate genes for genetic modification.