Low-Molecular-Weight Heparin Enhanced Therapeutic Effects of Human Adipose-Derived Stem Cell Administration in a Mouse Model of Lupus Nephritis

BackgroundLupus nephritis is a life-threatening complication in systemic lupus erythematosus (SLE), but the efficiency of current therapies involving corticosteroids, immunosuppressants, and biological agents is limited. Adipose-derived mesenchymal stem cells (ASCs) are gaining attention as a novel treatment for inflammation in SLE. Low-molecular-weight heparin (LMWH) exhibits multiple functions including anti-inflammatory, anti-fibrotic, and cell function-promoting effects. LMWH stimulation is expected to increase the therapeutic effect of ASCs by promoting cellular functions. In this study, we investigated the effects of LMWH on ASC functions and the therapeutic effect of LMWH-activated human-ASCs (hep-hASCs) in an SLE mouse model.MethodsThe cellular functions of human-derived ASCs stimulated with different LMWH concentrations were observed, and the optimum LMWH dose was selected. The mice were assigned to control, human-ASC, and hep-hASC groups; treatments were performed on week 20. Twenty-six week-old mice were sacrificed, and urine protein score, serum blood urea nitrogen, creatinine (Cr), anti-ds DNA IgG antibody, and serum IL-6 levels were analyzed in each group. Mice kidneys were evaluated via histological examination, immunohistochemical staining, and gene expression levels.ResultsLMWH significantly promoted ASC migration and proliferation and hepatocyte growth factor production and upregulated immunomodulatory factors in vitro. Hep-hASC administration resulted in significant disease activity improvement including proteinuria, serum Cr and IL-6 levels, anti-ds DNA IgG antibody, glomerulonephritis, and immune complex in mice. Inflammation and fibrosis in kidneys was significantly suppressed in the hep-hASC group; the gene expression levels of TNF-alpha, TIMP-2, and MMP-2 was significantly downregulated in the hep-hASC group compared with the control group.ConclusionsHep-hASC exhibited higher anti-inflammatory and anti-fibrotic effects than hASCs and may be a candidate tool for SLE treatment in future.

Remodeling Articular Immune Homeostasis with an Efferocytosis-inspired Nanoimitator Mitigates Rheumatoid Arthritis

Massive intra-articular infiltration of the pro-inflammatory macrophages is a prominent feature of rheumatoid arthritis (RA) lesions, which are thought to underlie articular immune dysfunction, severe synovitis and ultimate joint erosion. Here we report an efferocytosis-inspired nanoimitator (EINI) for in situ targeted reprogramming of the synovial inflammatory macrophages (SIMs) and thus thwarting their autoimmune attack and reinstating articular immune homeostasis, which mitigates RA. The EINI consisted of a drug-based core with an oxidative stress-responsive phosphatidylserine (PtdSer) corona and a shell of P-selectin-blocking motif, low molecular weight heparin (LMWH). When systemically administrated, the LMWH on the EINI first bound to P-selectin overexpressed on endothelium in subsynovial capillaries, which functioned as an antagonist disrupting neutrophils synovial trafficking. Due to the high dysregulation of the synovial microvasculature, the EINI subsequently enriched in joint synovium where the shell was exfoliated upon the reactive oxygen species stimulation, and PtdSer corona was then exposed. In an efferocytosis-like manner, the PtdSer-coroneted core was in turn phagocytosed by SIMs, which synergistically terminated the SIMs-initiated pathological cascades and serially reconstructed the intra-articular immune homeostasis, conferring a chondroprotection effect. These findings demonstrate that SIMs can be precisely remodeled via the efferocytosis-mimetic strategy, which holds great potential for RA treatment.

Affinity and Specificity for Binding to Glycosaminoglycans Can Be Tuned by Adapting Peptide Length and Sequence

Although glycosaminoglycan (GAG)–protein interactions are important in many physiological and pathological processes, the structural requirements for binding are poorly defined. Starting with GAG-binding peptide CXCL9(74-103), peptides were designed to elucidate the contribution to the GAG-binding affinity of different: (1) GAG-binding motifs (i.e., BBXB and BBBXXB); (2) amino acids in GAG-binding motifs and linker sequences; and (3) numbers of GAG-binding motifs. The affinity of eight chemically synthesized peptides for various GAGs was determined by isothermal fluorescence titration (IFT). Moreover, the binding of peptides to cellular GAGs on Chinese hamster ovary (CHO) cells was assessed using flow cytometry with and without soluble GAGs. The repetition of GAG-binding motifs in the peptides contributed to a higher affinity for heparan sulfate (HS) in the IFT measurements. Furthermore, the presence of Gln residues in both GAG-binding motifs and linker sequences increased the affinity of trimer peptides for low-molecular-weight heparin (LMWH), partially desulfated (ds)LMWH and HS, but not for hyaluronic acid. In addition, the peptides bound to cellular GAGs with differential affinity, and the addition of soluble HS or heparin reduced the binding of CXCL9(74-103) to cellular GAGs. These results indicate that the affinity and specificity of peptides for GAGs can be tuned by adapting their amino acid sequence and their number of GAG-binding motifs.

Coronavirus disease 2019 associated stroke in a toddler – A case report

Background: Stroke, an infrequent entity in children, usually presents with headache, reduced cognition, and seizures as frequent findings. The association of paediatric stroke with Coronavirus disease 2019 (COVID-19) is unknown with only a hand full of postulated hypotheses till date. Clinical Description: A 2-year-old child with sudden onset focal neurological deficits and high COVID antibody titters has been reported soon after a brief episode of cough and cold. Magnetic resonance imaging brain suggested infarct in posterior cerebral circulation. All other inflammatory markers and prothrombotic work-up were normal pointing toward a territorial affliction. Management: Child responded well to anticoagulants (low molecular weight heparin and aspirin) with complete neurological recovery. Conclusion: Possibility of COVID-19 associated regional endotheliitis is very high in the aforesaid toddler. Our case is the youngest reported case of paediatric stroke with a possible association with COVID-19.