Withdrawn: Lipid nanoparticles co-loaded with miRNA-22 and methotrexate for enhanced anti-inflammatory response in rheumatoid arthritis
Authors: Zhen-Yi Long
Si-Xian Wu
Hao Yuan
Yi-Feng Zhou
Ya-Meng Peng
Journal: Bioscience Reports (2020)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Rheumatoid arthritis; apoptosis; inflammatory reactions; methotrexate; miR-22.
Affiliations: Xiangya School of Medicine, Central South University, Changsha, China, Hunan province people's hospital, Hunan, China, Hunan Provincial People’s Hospital, Furong District, Changsha, Hunan, China

Abstract:  Present investigation was aimed at developing methotrexate (MTX) and miR-22 mimics-loaded lipid nanoparticles for the effective treatment of rheumatoid arthritis. The dual therapeutics loaded nanoparticles was prepared and subjected to in vitro and in vivo characterizations. The in vivo study was performed on adjuvant- induced arthritis model. The addition of IL-1β significantly decreased the expression of miR-22 levels in negative control groups, whereas miR-22 mimics treated cells showed significantly higher miR-22 expression compared to both the NC groups. MTX+miR-22 showed significantly lower cell viability compared to that of free MTX indicating a synergistic anti-inflammatory in the MH7A cells. To be specific, MTX/miR-22-loaded lipid nanoparticles (MTmiR-NP) showed the significantly lower cell viability compared to any other group indicating the potential of lipid nanoparticles. Consistently, MTmiR-NP exhibited a significantly higher cell apoptosis (~50%) compared to any other tested group further reiterating the nanoparticle-based combinational therapeutics. MTmiR-NP exhibited the significant reduction in the paw thickness and significantly lower arthritic score compared to all other groups on all time points. Present study clearly highlights the potential of lipid nanoparticles-based synergistic combination of MTX and miR-22 in achieving higher therapeutic response in rheumatoid arthritis treatment. 

Retracted: No

PubPeer comments:
 I am a bit confused about some of the data and results presented in this paper, and hope the authors can clarify. I have more critical comments on the binding analysis, but I ll leave those for a personal communication if the authors so desire. My first confusion arises from the CD spectra in Figure 3, and figure 3A in particular. The CD spectrum of lysozyme (HEWL) looks like none that I have ever measured myself, nor like any I have ever seen in the scientific literature. Just as an example, see Figure 7 in http: www.jbc.org content 250 17 6977.full.pdf. Could the authors perhaps check the x-axis scale? A further confusion with the CD is the apparent mismatch between the indicated concentrations of the ligand in the Figure (2, 4, 6, 8, and 10 u00b5M) and the concentrations indicated in Table 3, which are all a factor 10 lower. Could the authors please indicate what the correct concentrations were? A final confusion I have with regard to the CD is why the authors chose this concentration range. If the binding analysis is correct (and I am not so sure it is!), a binding constant of 2.5*10^4, 1 u00b5M protein, and 10 u00b5M ligand means that only 20% of the protein has a ligand bound. That complicates the analysis of potential structural changes significantly. It gets worse if the highest added ligand concentration was actually only 1 u00b5M, as in that case a mere 2.5% of the protein molecules has a ligand bound. My second confusion centers on the IR spectra. It is a bit strange to show these spectra in transmission mode, but one confusion is related to the peak assignments: the authors assign the 1290, 1420 and 1550 cm-1 bands to C-O stretching, C-H bending and N-H bending C=N stretching of the protein backbone. This is quite different from the band assignments of a large body of literature on protein structural analysis by IR (including, it should be noted, my own papers on the topic). See as just one example a review by Barth on this topic, primarily section 8.1: https: doi.org 10.1016 j.bbabio.2007.06.004 Can the authors please provide a reference that supports their band assignments? A further confusion here is the indicated concentrations of added ligand. It is not clear what the protein concentration is, but considering the fact there are some protein absorption bands, it will have been well above 1 u00b5M. The added ligand concentrations according to Figure 4 are in the low nM range, however. Assuming my estimation of the protein concentration is within the right ballpark, this means there will be less than 1% of protein molecules with a ligand bound, even in the case of a very strong binding. This then makes it impossible to see any structural changes, as 99% of the HEWL should still have its native structure. Could the authors please clarify the used concentrations? I would also note that the band at 1600-1700 cm-1 appears to be primarily the water absorption band - the Amide I should never be so much larger than the Amide II band in a protein (see also Bartsch paper referenced earlier). My final confusion with the IR results is the authors explanation for the disappearing absorption bands: a loss of vibrational freedom. I am having a hard time imagining how binding of a ligand can abolish vibrational motions, unless the binding completely destroys the actual bond. It is also possible that bands broaden, primarily due to hydrogen bonding, but in that case one would also expect major changes in the secondary structure of the protein - and the CD suggests there is hardly any change. My third confusion relates to the DLS data. The authors find that the protein in solution, without ligand, has a diameter of 400+ nm. As the authors note, this indicates the protein is aggregated. But does this then not affect all other measurements, too? Apparently the authors are then looking at a physically degraded sample, not at the native protein. Of course, the appearance of aggregates may well be due to the sample having such a high protein concentration ( 70 mg ml), meaning the protein is not well solubilized. My final confusion centers around the DSC data, where the method used is not described at all. Are these measurements on solutions? On solids (and how were these prepared)? On crystals? If these are solutions, I do not quite understand how the authors measured a glass transition temperature. Can the authors please clarify? ,