Therapeutic efficacy of a potent anti-Venezuelan equine encephalitis virus antibody is contingent on Fc effector function.

The development of specific, safe, and potent monoclonal antibodies (Abs) has led to novel therapeutic options for infectious disease. In addition to preventing viral infection through neutralization, Abs can clear infected cells and induce immunomodulatory functions through engagement of their crystallizable fragment (Fc) with complement proteins and Fc receptors on immune cells. Little is known about the role of Fc effector functions of neutralizing Abs in the context of encephalitic alphavirus infection. To determine the role of Fc effector function in therapeutic efficacy against Venezuelan equine encephalitis virus (VEEV), we compared the potently neutralizing anti-VEEV human IgG F5 (hF5) Ab with intact Fc function (hF5-WT) or containing the loss of function Fc mutations L234A and L235A (hF5-LALA) in the context of VEEV infection. We observed significantly reduced binding to complement and Fc receptors, as well as differential in vitro kinetics of Fc-mediated cytotoxicity for hF5-LALA compared to hF5-WT. The in vivo efficacy of hF5-LALA was comparable to hF5-WT at -24 and + 24 h post infection, with both Abs providing high levels of protection. However, when hF5-WT and hF5-LALA were administered + 48 h post infection, there was a significant decrease in the therapeutic efficacy of hF5-LALA. Together these results demonstrate that optimal therapeutic Ab treatment of VEEV, and possibly other encephalitic alphaviruses, requires neutralization paired with engagement of immune effectors via the Fc region.

Recombinant Protein Micelles to Block Transduction by SARS-CoV-2 Pseudovirus.

The continuing emergence of variants of the SARS-CoV-2 virus requires the development of modular molecular therapies. Here, we engineered a recombinant amphiphilic protein, oleosin, to spontaneously self-assemble into multivalent micellar nanostructures which can block the Spike S1 protein of SARS-CoV-2 pseudoviruses (PVs). Short recombinant proteins like oleosin can be formulated more easily than antibodies and can be functionalized with precision through genetic engineering. We cloned S1-binding mini-protein genes called LCBx, previously designed by David Baker's laboratory (UW Seattle), to the N-terminus of oleosin, expressing Oleo-LCBx proteins in E. coli. These proteins largely formed 10-100 nm micelles as verified by dynamic light scattering. Two proteins, Oleo-LCB1 and Oleo-LCB3, were seen to completely and irreversibly block transduction by both wild-type and delta variant PVs into 293T-hsACE2 cells at 10 µM. Presented in multivalent micelles, these proteins reduced transduction by PVs down to a functional protein concentration of 5 nM. Additionally, Oleo-LCB1 micelles outperformed corresponding synthetic LCB1 mini-proteins in reducing transduction by PVs. Tunable aqueous solubility of recombinant oleosin allowed incorporation of peptides/mini-proteins at high concentrations within micelles, thus enhancing drug loading. To validate the potential multifunctionality of the micelles, we showed that certain combinations of Oleo-LCB1 and Oleo-LCB3 performed much better than the individual proteins at the same concentration. These micelles, which we showed to be non-toxic to human cells, are thus a promising step toward the design of modular, multifunctional therapeutics that could bind to and inactivate multiple receptors and proteins necessary for the infection of the SARS-CoV-2 virus.

Racial disparities in post-stroke functional outcomes in young patients with ischemic stroke.

BACKGROUND AND PURPOSE: Recent studies show rising incidence of stroke in the young, for which risk factors are not well characterized. There is evidence of increased risk in certain racial and ethnic groups. We assessed racial differences in risk factors, stroke etiology, and outcomes among young stroke patients. METHODS: Using data from our inpatient registry for ischemic stroke, we reviewed patients aged 18-50 who were admitted 01/2013 to 04/2018. Race/ethnicity were characterized as non-Hispanic White (NHW), non-Hispanic Black (NHB), Hispanic (HIS). For univariate comparisons Chi-square and Kruskal-Wallis tests were performed as appropriate. Multivariable logistic regression was used to assess impact of race on day seven modified Rankin score (mRS). RESULTS: Among 810 patients with race and outcome data who were admitted in the study period, median age was 43, 57.1% were male, and 36.5% NHW, 43.2% NHB, 20.2% HIS. History of hypertension (HTN), type II diabetes (DM II), smoking, heart failure (CHF), prior stroke, and end-stage renal disease varied significantly by race. Compared to NHW, NHB had higher odds of HTN (OR 2.28, 1.65-3.15), CHF (OR 2.17, 1.06-4.46), and DM II 1.92 (1.25-2.94) while HIS had higher odds of DM II (OR 2.52, 1.55-4.10) and lower odds of smoking (OR 0.56, 0.35-0.90). Arrival NIHSS was higher in NHB, but etiology and rates of tpA treatment and thrombectomy did not vary by race. Compared to NHW patients, NHB (OR 0.50 CI (0.31-0.78)) and HIS (OR 0.37 CI (0.21-0.67)) were less likely to have good functional outcome (mRS <2) at day 7 in adjusted analyses. CONCLUSIONS: In this study, there was a higher prevalence of several modifiable risk factors in NHB and HIS young stroke patients and early functional outcome was worse in these groups. Our study suggests a need for targeted prevention efforts for younger populations at highest risk for stroke.

Caring for one of our own.

Schwartz Center Rounds are monthly multidisciplinary meetings where caregivers reflect on important psychosocial issues that they, along with patients and their families, face and gain insight and support from fellow staff members, with the goal of advancing compassionate health care, supporting caregivers, and fostering the connection between a clinician and his or her patients. This Schwartz Round focused on boundaries and the particular privileges and pressures of caring for a member of the staff. The article explores the tension between professional courtesy and empathic engagement. Major transitions can include the intrinsic fear of abandonment. Being "connected" is an important aspect of the patient-caregiver relationship. Patient-centered care requires that we balance clinical acumen and medical technology with humanism throughout the different phases of a patient's experience with a life-threatening illness.

DJ-1 transcriptionally up-regulates the human tyrosine hydroxylase by inhibiting the sumoylation of pyrimidine tract-binding protein-associated splicing factor.

Loss-of-function mutations in DJ-1 cause a subset of familial Parkinson disease (PD). However, the mechanism underlying the selective vulnerability in dopaminergic pathway due to the inactivation of DJ-1 is unclear. Previously, we have reported that DJ-1 is a neuroprotective transcriptional co-activator interacting with the transcriptional co-repressor pyrimidine tract-binding protein-associated splicing factor (PSF). Here we show that DJ-1 and PSF bind and regulate the human tyrosine hydroxylase (TH) promoter. Inactivation of DJ-1 by small interference RNA (siRNA) results in decreased TH expression and l-DOPA production in human dopaminergic cell lines. Consistent with its role as a transcriptional regulator, DJ-1 specifically suppresses the global SUMO-1 modification. High molecular weight sumoylated protein species, including PSF, accumulate in the lymphoblast cells from the patients carrying pathogenic DJ-1 mutations. DJ-1 elevates the TH expression by inhibiting the sumoylation of PSF and preventing its sumoylation-dependent recruitment of histone deacetylase 1. Furthermore, siRNA silencing of DJ-1 decreases the acetylation of TH promoter-bound histones, and histone deacetylase inhibitors restore the DJ-1 siRNA-induced repression of TH. Therefore, our results suggest DJ-1 as a regulator of protein sumoylation and directly link the loss of DJ-1 expression and transcriptional dysfunction to impaired dopamine synthesis.

The Parkinson's disease-associated DJ-1 protein is a transcriptional co-activator that protects against neuronal apoptosis.

Mutations in the DJ-1 gene cause early-onset autosomal recessive Parkinson's disease (PD), although the role of DJ-1 in the degeneration of dopaminergic neurons is unresolved. Here we show that the major interacting-proteins with DJ-1 in dopaminergic neuronal cells are the nuclear proteins p54nrb and pyrimidine tract-binding protein-associated splicing factor (PSF), two multifunctional regulators of transcription and RNA metabolism. PD-associated DJ-1 mutants exhibit decreased nuclear distribution and increased mitochondrial localization, resulting in diminished co-localization with co-activator p54nrb and repressor PSF. Unlike pathogenic DJ-1 mutants, wild-type DJ-1 acts to inhibit the transcriptional silencing activity of the PSF. In addition, the transcriptional silencer PSF induces neuronal apoptosis, which can be reversed by wild-type DJ-1 but to a lesser extent by PD-associated DJ-1 mutants. DJ-1-specific small interfering RNA sensitizes cells to PSF-induced apoptosis. Both DJ-1 and p54nrb block oxidative stress and mutant alpha-synuclein-induced cell death. Thus, DJ-1 is a neuroprotective transcriptional co-activator that may act in concert with p54nrb and PSF to regulate the expression of a neuroprotective genetic program. Mutations that impair the transcriptional co-activator function of DJ-1 render dopaminergic neurons vulnerable to apoptosis and may contribute to the pathogenesis of PD.