Faculty Bibliography

Among the ways by which oncogenic KRAS upregulates glycolysis in cancer is direct interaction of KRAS4A with hexokinase 1 (HK1), but the mechanism is unknown. HK1 associates with the outer mitochondrial membrane (OMM) where its allosteric regulation depends on homodimerization. Using affinity capture, FRET, and blue native gels, we show that KRAS4A enhances oligomerization of HK1 on the OMM. Modeling the HK1/KRAS4A complex with AlphaFold3 predicts that the membrane association sequences of both HK1 and KRAS4A are oriented toward the OMM. Super-resolution microscopy showed colocalization of HK1 and KRAS4A on the OMM with HK1 enriched at discrete locations. Single-molecule tracking reveals HK1 diffusing freely along the OMM and dwelling at discrete regions where two molecules can be seen to colocalize transiently. KRAS4A expression decreased the diffusion coefficient of HK1 on the organelle. Thus, KRAS4A alters the dynamics of HK1 on the OMM and promotes oligomerization.

Tauopathies are neurodegenerative diseases characterized by pathological tau accumulation, leading to motor and neuropsychiatric symptoms. Effective tau-targeting therapies remain a major challenge, in part because tau lacks well-defined druggable sites and accumulates as heterogeneous intracellular aggregates that are difficult to access and clear. Here, we present 1D9-LIRΔTP53INP2, a single-domain antibody (sdAb)-based protein degrader that facilitates tau clearance through the autophagy-lysosomal pathway. This engineered molecule combines the anti-tau sdAb 1D9 with an LC3-interacting region (LIRΔTP53INP2) to promote autophagosomal recruitment, mimicking autophagy receptors by simultaneously binding tau and LC3. In neurons derived from patients with frontotemporal dementia (FTD) and JNPL3 tauopathy mice, both harboring the P301L tau mutation, 1D9-LIRΔTP53INP2 promoted autophagy-lysosome-mediated tau degradation. It readily crossed the blood-brain barrier and improved motor function in JNPL3 tauopathy mice. These findings underscore the therapeutic potential of sdAb-based protein degraders for tauopathies. Given the challenges of brain delivery for conventional antibodies, sdAbs with enhanced brain penetration and efficacy offer a promising strategy for treatment of neurodegenerative diseases.

BACKGROUND/UNASSIGNED:Despite decades of research, the development of an effective HIV vaccine remains a significant challenge. Recent findings from three large vaccine efficacy trials have identified antibodies against the V1V2 domain of the HIV envelope glycoprotein as a potential correlate of reduced infection risk, offering a promising avenue for improving vaccine efficacy. Vaccine-elicited anti-V1V2 antibodies do not mediate potent virus-neutralizing activities, but they mediate Fc-dependent effector functions. METHODS/UNASSIGNED:This study evaluated the capacity of V1V2-scaffold vaccines in different formulations to generate antibody responses with Fc-mediated functions. BALB/c mice were immunized with V1V2-scaffold proteins formulated with one of the following adjuvants: MF59-like squalene-based oil-in-water emulsion (Addavax), a combination of TLR7/8 and RIG-I agonists (IMDQ-PC/IVT), nanoemulsion and RIG-I agonist (NE/IVT), or empty lipid nanoparticles (eLNP). All formulations were administered intramuscularly except NE/IVT, which was given intranasally. For comparison, we also tested a V1V2-scaffold-expressing mRNA-LNP vaccine delivered intramuscularly and an Env gp140 protein with liposomal MPLA/DDA adjuvant administered subcutaneously. RESULTS/UNASSIGNED:Among the six vaccine formulations tested, V1V2-scaffold immunogens adjuvanted with LNP (eLNP and mRNA-LNP) elicited the most robust and cross-reactive serum IgG responses that recognized native Env on cell surfaces or virions. The eLNP and mRNA-LNP groups, along with IMDQ-PC/IVT, also elicited functional IgG2a, and correspondingly displayed Fc-mediated activities, as measured by antibody-dependent cellular phagocytosis and FcγRIV binding. Notably, IMDQ-PC/IVT elicited predominantly IgG2a with minimal IgG1, eLNP stimulated IgG1 and IgG2a with IgG1 dominance, whereas mRNA-LNP yielded more balanced IgG2a/IgG1 responses. CONCLUSIONS/UNASSIGNED:Data from this study provide new insights into the utility of novel formulations for V1V2-scaffold immunogens as a strategy for optimizing the induction of functional V1V2-specific antibodies to improve HIV vaccine efficacy.

Systemic vaccination of macaques with V1-deleted (ΔV1) envelope immunogens reduce the risk of SIV_mac251 acquisition by approximately 60%, with protective roles played by V2-specific ADCC and envelope-specific mucosal IL-17⁺NKp44⁺ innate lymphoid cells (ILCs). We investigated whether increased mucosal responses to V2 benefit vaccine efficacy by delivering oral nanoparticles (NPs) that release V2-scaffolded on Typhoid Toxin B (TTB) to the large intestine. Strikingly, mucosal immunization of male macaques abrogated vaccine efficacy with control TTB or empty NPs, but vaccine efficacy of up to 47.6% was preserved with V2-TTB NPs. The deleterious effects of NPs were linked to preferential recruitment of mucosal plasmacytoid dendritic cells (pDCs), reduction of protective mucosal NKp44⁺ ILCs, increased non-protective mucosal PMA/Ionomycin-induced IFN-γ⁺NKG2A^-NKp44^-ILCs, and increased levels of mucosal activated Ki67⁺CD4⁺ T cells, a potential target for virus infection. V2-TTB NP mucosal boosting rescued vaccine efficacy, likely via high avidity V2-specific antibodies mediating ADCC, and higher frequencies of mucosal NKp44⁺ ILCs and of ∆V1gp120 binding antibody-secreting B cells in the rectal mucosa. These findings emphasize the central role of systemic immunization and mucosal V2-specific antibodies in the protection afforded by ΔV1 envelope immunogens and encourage careful evaluation of vaccine delivery platforms to avoid inducing immune responses favorable to HIV transmission.

Bacteria dysbiosis and its accompanying inflammation or compromised mucosal integrity is associated with an increased risk of HIV-1 transmission. However, HIV-1 may also bind bacteria or bacterial products to impact infectivity and transmissibility. This study evaluated HIV-1 interactions with bacteria through glycan-binding lectins. The Streptococcal Siglec-like lectin SLBR-N, a part of the fimbriae shrouding the bacteria surface that recognizes α2,3 sialyated O-linked glycans, was noted for its ability to enhance HIV-1 infectivity in the context of cell-free infection and cell-to-cell transfer. Enhancing effects were recapitulated with O-glycan-binding plant lectins, signifying the importance of O-glycans. N-glycan-binding bacterial lectins FimH and Msl had no effect. SLBR-N was demonstrated to capture and transfer infectious HIV-1 virions, bind to O-glycans on HIV-1 Env, and increase HIV-1 resistance to neutralizing antibodies targeting different regions of Env. This study highlights the potential contribution of O-glycan-binding lectins from commensal bacteria at the mucosa in promoting HIV-1 infection.

INTRODUCTION/UNASSIGNED:HIV-1 envelope (Env) is the key target for antibodies (Abs) against the virus and thus an important HIV-1 vaccine component. Env is synthesized from a gp160 precursor with a signal peptide (SP) at its N-terminus. This study investigated the influence of the SP on Env antigenicity and immunogenicity. METHODS/UNASSIGNED:Env proteins from two HIV-1 isolates, AA05 and AC02, were analyzed as gp120 and gp160 in their native wild-type (WT) forms and as chimeras with swapped SPs (AA05-02 and AC02-05). The WT and chimeric Env were assessed for antigenicity and glycosylation using monoclonal antibodies (mAbs) and glycan probes. Immunogenicity was tested in mice using three vaccine types: gp120 protein, gp120 DNA+gp120 protein, and gp120 DNA+gp160 DNA. RESULTS/UNASSIGNED:The recombinant AC02 gp120 protein was antigenically superior to AA05 as indicated by higher reactivity with most mAbs tested. When SPs were swapped, the antigenicity of the chimeric gp120s (AA05-02 and AC02-05) resembled that of the gp120s from which the SPs were derived; AA05-02 was similar to AC02 and vice versa. Glycan probe reactivity followed a similar pattern: AA05-02 and AC02 showed similar affinity to high-mannose specific mAbs and lectins. Interestingly, the antigenicity of gp160s showed an opposite pattern; membrane-bound gp160 expressed with the AA05 SP (AA05 and AC02-05) showed greater mAb binding than gp160 with the AC02 SP (AC02 and AA05-02). Mice immunized with gp120 protein showed that AA05-02 induced stronger cross-reactive binding Ab responses than AA05 WT, and AC02 elicited stronger responses than AC02-05, indicating AC02 SP enhanced gp120 immunogenicity. However, when DNA vaccines were included (gp120 DNA+gp120 protein and gp120 DNA+gp160 DNA), the use of heterologous SPs diminished the immunogenicity of the WT immunogens. Among the three vaccine regimens tested, only gp120 DNA+gp160 DNA immunization elicited low-level Tier 2 neutralizing Abs, with AA05 WT inducing Abs with greater neutralization capabilities than AA05-02. CONCLUSION/UNASSIGNED:These data demonstrate that the SP can significantly impact the antigenicity and immunogenicity of HIV-1 Env proteins. Hence, while SP swapping is a common practice in constructing Env immunogens, this study highlights the importance of careful consideration of the effects of replacing native SPs on the immunogenicity of Env vaccines.

Tauopathies are a group of neurodegenerative diseases characterized by the presence of tau inclusions. We have developed over fifty anti-tau single-domain antibodies (sdAbs) derived from phage display libraries of a llama immunized with recombinant and pathological tau immunogens. We examined the therapeutic potential of four of these sdAbs in a Drosophila tauopathy model following their transgenic expression either in all neurons or neuronal subtypes. Three of these sdAbs showed therapeutic potential in various assays, effectively clearing pathological tau and attenuating or preventing tau-induced phenotypes that typically manifest as defects in neuronal axonal transport, neurodegeneration, functional impairments, and shortened lifespan. Of these three, one sdAb was superior in every assay, which may at least in part be attributed to its tau-binding epitope. These findings support its development as a gene therapy for tauopathies.

Programmed cell death-1 (PD-1) is a potent immune checkpoint receptor on T lymphocytes. Upon engagement by its ligands, PD-L1 or PD-L2, PD-1 inhibits T cell activation and can promote immune tolerance. Antagonism of PD-1 signaling has proven effective in cancer immunotherapy, and conversely, agonists of the receptor may have a role in treating autoimmune disease. Some immune receptors function as dimers, but PD-1 has been considered monomeric. Here, we show that PD-1 and its ligands form dimers as a consequence of transmembrane domain interactions and that propensity for dimerization correlates with the ability of PD-1 to inhibit immune responses, antitumor immunity, cytotoxic T cell function, and autoimmune tissue destruction. These observations contribute to our understanding of the PD-1 axis and how it can potentially be manipulated for improved treatment of cancer and autoimmune diseases.

Synucleinopathies are a group of neurodegenerative diseases characterized by the accumulation of α-synuclein (α-syn) in the brain, leading to motor and neuropsychiatric symptoms. Currently, there are no known cures for synucleinopathies, and treatments mainly focus on symptom management. In this study, we developed a single-domain antibody (sdAb)-based protein degrader with features designed to enhance proteasomal degradation of α-syn. This sdAb derivative targets both α-syn and Cereblon (CRBN), a substrate-receptor for the E3-ubiquitin ligase CRL4^CRBN, and thereby induces α-syn ubiquitination and proteasomal degradation. Our results indicate that this therapeutic candidate enhances proteasomal degradation of α-syn, in addition to the endogenous lysosomal degradation machinery. By promoting proteasomal degradation of α-syn, we improved clearance of α-syn in primary culture and mouse models of synucleinopathy. These findings indicate that our sdAb-based protein degrader is a promising therapeutic candidate for synucleinopathies. Considering that only a small percentage of antibodies enter the brain, more potent sdAbs with greater brain entry than whole antibodies could enhance clinical benefits of antibody-based therapies.

Synucleinopathies are a group of neurodegenerative diseases characterized by the accumulation of α-synuclein (α-syn) in the brain, leading to motor and neuropsychiatric symptoms. Currently, there are no known cures for synucleinopathies, and treatments mainly focus on symptom management. In this study, we developed a single-domain antibody (sdAb)-based protein degrader with features designed to enhance proteasomal degradation of α-syn. This sdAb derivative targets both α-syn and Cereblon (CRBN), a substrate-receptor for the E3-ubiquitin ligase CRL4^CRBN, and thereby induces α-syn ubiquitination and proteasomal degradation. Our results indicate that this therapeutic candidate enhances proteasomal degradation of α-syn, in addition to the endogenous lysosomal degradation machinery. By promoting proteasomal degradation of α-syn, we improved clearance of α-syn in primary culture and mouse models of synucleinopathy. These findings indicate that our sdAb-based protein degrader is a promising therapeutic candidate for synucleinopathies. Considering that only a small percentage of antibodies enter the brain, more potent sdAbs with greater brain entry than whole antibodies could enhance clinical benefits of antibody-based therapies.