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RNA interference (RNAi) and autophagy are two pivotal biological processes that regulate virus replication. This study explored the complex relationship between autophagy and RNAi in controlling influenza virus replication. Initially, we reported that influenza virus (H9N2) infection increases the viral load and the expression of autophagy markers while inhibiting the RNAi pathway. Subsequent studies employing autophagy enhancer and inhibitor treatments confirmed that avian influenza virus (AIV, H9N2) promotes viral replication by enhancing autophagy pathways. Further analysis revealed that ATG7, an autophagy protein, can interact with dicer to affect its antiviral functions. Finally, we discovered that infection with other avian RNA viruses, including infectious bursal disease virus (IBDV) and infectious bronchitis virus (IBV), induced the upregulation of ATG7, which blocked the RNAi pathway to facilitate virus replication. Our findings suggested that virus infection might trigger the upregulation of autophagy and downregulation of the RNAi pathway, revealing a complex interaction between these two biological processes in the defence against viral replication. [ABSTRACT FROM AUTHOR]

Background: Osteoporosis (OP) and osteomalacia (OM) are metabolic bone diseases characterized by mineral and matrix density changes. Quantitative bone matrix density differentiates OM from OP. MRI is a noninvasive and nonionizing imaging technique that can measure bone matrix density quantitatively in ex vivo and in vivo. Purpose: To demonstrate water + fat suppressed 1H MRI to compute bone matrix density in ex vivo rat femurs in the preclinical model. Study Type: Prospective. Animal Model: Fifteen skeletally mature female Sprague–Dawley rats, five per group (normal, ovariectomized (OVX), partially nephrectomized/vitamin D (Vit‐D) deficient), 250–275 g, ∼15 weeks old. Field Strength/Sequence: 7T, zero echo time sequence with water + fat (VAPOR) suppression capability, μCT imaging, and gravimetric measurements. Assessment: Cortical and trabecular bone segments from normal and disease models were scanned in the same coil along with a dual calibration phantom for quantitative assessment of bone matrix density. Statistical Tests: ANOVA and linear regression were used for data analysis, with P‐values <0.05 statistically significant. Results: The MRI‐derived three‐density PEG pellet densities have a strong linear relationship with physical density measures (r2 = 0.99). The Vit‐D group had the lowest bone matrix density for cortical bone (0.47 ± 0.16 g cm−3), whereas the OVX had the lowest bone matrix density for trabecular bone (0.26 ± 0.04 g cm−3). Gravimetry results confirmed these MRI‐based observations for Vit‐D cortical (0.51 ± 0.07 g cm−3) and OVX trabecular (0.26 ± 0.03 g cm−3) bone groups. Data Conclusion: Rat femur images were obtained using a modified pulse sequence and a custom‐designed double‐tuned (1H/31P) transmit‐receive solenoid‐coil on a 7T preclinical MRI scanner. Phantom experiments confirmed a strong linear relation between MRI‐derived and physical density measures and quantitative bone matrix densities in rat femurs from normal, OVX, and Vit‐D deficient/partially nephrectomized animals were computed. Level of Evidence: 2 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Purpose: To implement solid state 31P MRI (31P SMRI) in a clinical scanner to visualize bone mineral. Materials and Methods: Wrists of seven healthy volunteers were scanned. A quadrature wrist 31P transmit/receive coil provided strong B1 and good signal-to-noise ratio (SNR). A 1H-31P frequency converter was constructed to enable detection of the 31P signal by means of the 1H channel. Data points lost in the receiver dead time were recovered by a second acquisition with longer dwell time and lower gradient strength. Results: Three-dimensional 31P images, showing only bone mineral of the wrist, were obtained with a clinical 3 Tesla (T) scanner. In the best overall case an image with isotropic resolution of ∼5.1 mm and SNR of 30 was obtained in 37 min. 31P NMR properties (resonance line width 2 kHz and T1 17-19 s) of in vivo human bone mineral were measured. Conclusion: In vivo 31P SMRI visualization of human wrist bone mineral with a clinical MR scanner is feasible with suitable modifications to circumvent the scanners' limitations in reception of short-T2 signals. Frequency conversion methodology is useful for implementing 31P SMRI measurements on scanners which do not have multinuclear capability or for which the multinuclear receiver dead time is excessive. J. Magn. Reson. Imaging 2011;. © 2011 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

RNA interference (RNAi) is a key antiviral immune mechanism in eukaryotes. However, antiviral RNAi in vertebrates has only been observed in cells with poor interferon systems or in viral suppressors of RNAi (VSR) deficiency virus infections. Our research discovered that infecting macrophages with wild-type coronavirus (Infectious bronchitis virus, IBV) and influenza viruses (Avian influenza virus, AIV) can trigger RNAi antiviral immunity and produce a certain amount of virus-derived siRNA (vsiRNA). These vsiRNAs have an inhibitory effect on the virus and carry out targeted silencing along the Dicer-Ago2-vsiRNA axis. Notably, these vsiRNAs are distributed throughout the virus's entire genome, with a predilection for A/U at the 5' and 3' termini of vsiRNA. In addition, Dicer cleavage produces vsiRNA based on the RWM motif, where R represents A/G, W represents A/C, and M represents A/U. We also discovered that avian LGP2 and MDA5 proteins positively impact the expression of the Dicer protein and the Dicer subtype "DicerM." Most importantly, the PS-vsiRNA plasmid combined with nanomaterial polyetherimide (PEI) showed excellent anti-virus activity in specific-pathogen-free (SPF) chickens. These findings show that RNA viruses trigger the production of the vsiRNA in avian somatic cells, which is of great significance for the application of therapeutic vaccines., (© The Author(s) 2025. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Background: Osteoporosis (OP) and osteomalacia (OM) are metabolic bone diseases characterized by mineral and matrix density changes. Quantitative bone matrix density differentiates OM from OP. MRI is a noninvasive and nonionizing imaging technique that can measure bone matrix density quantitatively in ex vivo and in vivo., Purpose: To demonstrate water + fat suppressed 1 H MRI to compute bone matrix density in ex vivo rat femurs in the preclinical model., Study Type: Prospective., Animal Model: Fifteen skeletally mature female Sprague-Dawley rats, five per group (normal, ovariectomized (OVX), partially nephrectomized/vitamin D (Vit-D) deficient), 250-275 g, ∼15 weeks old., Field Strength/sequence: 7T, zero echo time sequence with water + fat (VAPOR) suppression capability, μCT imaging, and gravimetric measurements., Assessment: Cortical and trabecular bone segments from normal and disease models were scanned in the same coil along with a dual calibration phantom for quantitative assessment of bone matrix density., Statistical Tests: ANOVA and linear regression were used for data analysis, with P-values <0.05 statistically significant., Results: The MRI-derived three-density PEG pellet densities have a strong linear relationship with physical density measures (r 2  = 0.99). The Vit-D group had the lowest bone matrix density for cortical bone (0.47 ± 0.16 g cm -3 ), whereas the OVX had the lowest bone matrix density for trabecular bone (0.26 ± 0.04 g cm -3 ). Gravimetry results confirmed these MRI-based observations for Vit-D cortical (0.51 ± 0.07 g cm -3 ) and OVX trabecular (0.26 ± 0.03 g cm -3 ) bone groups., Data Conclusion: Rat femur images were obtained using a modified pulse sequence and a custom-designed double-tuned ( 1 H/ 31 P) transmit-receive solenoid-coil on a 7T preclinical MRI scanner. Phantom experiments confirmed a strong linear relation between MRI-derived and physical density measures and quantitative bone matrix densities in rat femurs from normal, OVX, and Vit-D deficient/partially nephrectomized animals were computed., Level of Evidence: 2 TECHNICAL EFFICACY: Stage 2., (© 2024 International Society for Magnetic Resonance in Medicine.)