We present a comprehensive, in silico-designed CRISPR interference (CRISPRi) sgRNA database targeting the hypervirulent Streptococcus agalactiae strain COH1. This resource provides broad, redundant, and cross-strain functional coverage, enabling scalable CRISPRi-based interrogation of conserved and strain-specific determinants of GBS biology, colonization, and pathogenesis.

Group B Streptococcus (GBS), a common colonizer of the human genital and gastrointestinal tracts, is a leading cause of neonatal bacterial meningitis, which can lead to severe neurological complications. The hypervirulent serotype III, sequence type 17 (ST-17) strain COH1 is strongly associated with late-onset disease due to its unique set of virulence factors. However, genetic manipulation of ST-17 strains remains challenging, limiting the ability to study key pathogenic genes. In this study, we developed a CRISPR interference (CRISPRi) system utilizing an endogenous catalytically inactivated Cas9 (dCas9) in the COH1 strain, enabling targeted and tunable gene expression knockdown. We confirmed the efficacy of this system through hemolysis assays, qPCR transcriptional analysis, and in vitro infection models using human brain endothelial cells. The CRISPRi system successfully produced phenotypic knockdowns of key virulence genes, including PI-2b, srr2, and iagA, reducing adhesion, invasion, and inflammatory responses at the blood-brain barrier (BBB). This platform enables rapid gene knockdowns for functional genomics in ST-17 GBS, enabling high-throughput screening and pathogenesis research. IMPORTANCE:Group B Streptococcus (GBS) remains the world's leading cause of neonatal meningitis. GBS-host interactions at the blood-brain barrier (BBB) are dependent on bacterial factors, including surface factors and two-component systems. Multi-locus sequence type 17 (ST-17) GBS strains are highly associated with neonatal meningitis, and these strains harbor many virulence factors for infection at the BBB. Historically, these factors have been studied using traditional knockout mutagenesis, which has been challenging in the most common ST-17 lab strain, COH1. This study utilizes CRISPR interference (CRISPRi) to generate rapid expression knockdown. This study validates a CRISPRi-enabled COH1 dCas9 strain as a versatile tool for probing GBS pathogenesis at the BBB.

Coxsackievirus B3 (CVB3) is a picornavirus that causes systemic inflammatory diseases including myocarditis, pericarditis, pancreatitis, and meningoencephalitis. We have previously reported that CVB3 induces mitochondrial fission and mitophagy while inhibiting lysosomal degradation by blocking autophagosome-lysosome fusion. This promotes the release of virus-laden mitophagosomes from host cells as infectious extracellular vesicles (EVs), enabling non-lytic viral egress. Transient receptor potential vanilloid 1 (TRPV1), a heat and capsaicin-sensitive cation channel, regulates mitochondrial dynamics by inducing mitochondrial membrane depolarization and fission. In this study, we found that TRPV1 activation by capsaicin dramatically enhances CVB3 egress from host cells via EVs. Released EVs revealed increased levels of viral capsid protein VP1, mitochondrial protein TOM70, and fission protein phospho-DRP1. Moreover, these EVs were enriched in heat shock protein HSP70, suggesting its role in facilitating infectious EV release from cells. Furthermore, TRPV1 inhibition with capsazepine and SB-366791 significantly reduced viral infection in vitro. Our in vivo studies also found that SB-366791 significantly mitigates pancreatic damage and reduces viral titers in a mouse model of CVB3 pancreatitis. Given the lack of understanding regarding factors that contribute to diverse clinical manifestations of CVB3, our study highlights capsaicin and TRPV1 as potential exacerbating factors that facilitate CVB3 dissemination via mitophagy-derived EVs.

Streptococcus agalactiae (Group B Streptococcus , GBS) is a Gram-positive opportunistic pathogen and the leading cause of neonatal bacterial meningitis, a life-threatening infection of the central nervous system (CNS) that occurs when bacteria cross the blood-brain barrier (BBB). GBS commonly colonizes the maternal genital tract and is a major cause of invasive neonatal disease, including bacteremia and meningitis. Despite treatment advances, GBS meningitis remains associated with substantial mortality and long-term neurological sequelae. The BBB is a highly specialized barrier formed by brain endothelial cells (BECs) that restrict microbial entry into the CNS through tightly regulated intercellular junctions. The BBB exists within the neurovascular unit, where neurons and other CNS cell types actively regulate endothelial barrier properties through intercellular signaling. However, the contribution of neuronal-endothelial interactions to BBB function during neonatal meningitis remains poorly understood. To investigate the mechanisms by which GBS disrupts and penetrates the BBB, we utilized induced pluripotent stem cell (iPSC)-derived brain-like endothelial cells. EZ-Sphere-derived neurons generated from the same iPSC source were incorporated into an isogenic BBB model to determine whether neuronal-endothelial communication influences GBS interaction with BECs. Neuronal co-culture significantly reduced GBS adherence to and invasion of BECs while preserving tight junction integrity during infection. Application of neuron-conditioned medium similarly decreased bacterial adherence and invasion, suggesting that neuron-derived soluble factors enhance barrier integrity during GBS infection. Together, these findings demonstrate that neuronal signaling enhances BBB resistance to GBS and highlight a previously underappreciated role for neurovascular crosstalk in limiting bacterial pathogenesis. Importance:Group B Streptococcus (GBS) is the leading cause of bacterial meningitis in newborns. GBS interacts with and crosses the blood-brain barrier (BBB) contributing to a potentially fatal infection without treatment. Understanding how the BBB interacts with bacterial pathogens is critical for developing new strategies to protect vulnerable infants. In this study, we used human stem cell-derived models to recapitulate the BBB and examine how communication between brain endothelial cells and neurons influence host response to bacterial infection. These findings identify neuronal-endothelial communication as a potential contributor to BBB protection and provide a foundation for future studies aimed at preventing GBS invasion of the central nervous system.

Background: The blood-brain barrier (BBB) separates the circulation from the central nervous system (CNS) and serves to maintain brain homeostasis. The BBB comprises highly specialized brain endothelial cells (BECs) with unique properties that allow the BBB to maintain strict regulation of molecules entering and exiting the CNS. These characteristics include tight junctions, low endocytosis rates, and efflux and nutrient transporters. Breast cancer resistance protein (BCRP) is an efflux transporter found at the BBB that plays a key role in protecting the CNS. Together with other efflux transporters, BCRP contributes to multidrug-resistant cancers and difficulty delivering drugs and therapeutics to the brain and other organs. Methods: Using the hCMEC/D3 line, we utilized BCRP substrate rosuvastatin to effectively select for cells expressing high amounts of BCRP, thus generating hCMEC/D3-BCRP. To assess protein abundance, we utilized flow cytometry and confirmed expression via qPCR. To investigate BCRP efflux function in evolved hCMEC/D3-BCRP, we performed substrate accumulation assays with BCRP and P-gp substrates. Results: We found hCMEC/D3-BCRP had increased BCRP abundance and expression relative to parent hCMEC/D3. We also observed an increase in BCRP function via substrate accumulation of two BCRP substrates compared to parent hCMEC/D3. Conclusions: BCRP serves a protective role within the BBB and is a major hurdle in drug delivery. We generated a BCRP overexpression BEC cell line (hCMEC/D3-BCRP) under the influence of endogenous promoters. This cell line can be used to further investigate the role of BCRP in BECs and utilized in efflux transport studies.

Viral aseptic meningitis is a neuroinflammatory condition that occurs when viruses gain access to the central nervous system (CNS) and induce inflammation. The blood-brain barrier (BBB) is comprised of brain endothelial cells (BECs) that stringently regulate the passage of molecules, toxins, and pathogens from the circulation into the CNS. Through their unique properties, such as complex tight junctions, reduced rates of endocytosis, expression of efflux transporters, and restricted expression of leukocyte adhesion molecules, the BBB is often able to limit pathogen entry into the brain; however, certain neurotropic pathogens, such as coxsackievirus B3 (CVB3) are able to infect the CNS. We have previously demonstrated that CVB3 can infect and disrupt induced pluripotent stem cell-derived brain-like endothelial cells (iBECs), but the host response to this infection remains unknown. Here, we investigate global host transcriptional changes during CVB3 infection of iBECs using RNA sequencing. We validated our data set by exploring pathways altered by CVB3 using quantitative real-time PCR (qPCR) and enzyme-linked immunosorbent assay of upregulated cytokines and interferon signaling molecules. IMPORTANCE Coxsackievirus B3 (CVB3) is a leading cause of viral aseptic meningitis that can produce severe disease in susceptible individuals. To gain access to the central nervous system, CVB3 must cross central nervous system barriers, such as the blood-brain barrier. Previously, we have shown that CVB3 infects a human stem cell-derived brain-like endothelial cell model. Here, we report the global transcriptome of stem cell-derived brain-like endothelial cells to CVB3 infection and provide proof-of-concept validation of the dataset using molecular biology techniques. These data could inform novel mechanisms of CVB3-mediated blood-brain barrier dysfunction.

Streptococcus pneumoniae (pneumococcus) is an opportunistic pathogen that remains the leading cause of bacterial meningitis worldwide. For meningitis to occur, pneumococcus must breach the blood-brain barrier (BBB), a highly specialized network of brain endothelial cells that comprise the microvasculature of the brain. Here, we report the use of human induced pluripotent stem cell-derived brain-like endothelial cells (iBECs) to model the BBB during pneumococcal infection. iBECs were infected with the S. pneumoniae strain TIGR4. Adherence assays showed that pneumococcal adherence to iBECs was a saturable process. Moreover, deletion of two pneumococcal adhesins resulted in an adherence defect, supporting a receptor-mediated interaction between pneumococcus and iBECs. Next, the integrity of several tight junction components was assessed via western blot and RT-qPCR, revealing the loss of abundance and expression in iBECs during infection with pneumococcus. Simultaneously, the expression of VEGFA and the tight junction repressor SNAI1 was upregulated. Semi-automated analysis of junction images also demonstrated a loss of ZO-1 and occludin continuity during pneumococcal infection. Consistent with these findings, the loss of TEER and the increase in barrier permeability were observed in pneumococcus-infected iBECs. The toxin pneumolysin (Ply) was important for this disruption, as the loss of Ply in pneumococcus partially arrested the reduction of TEER and the increase in permeability. Finally, RT-qPCR showed that pneumococcus was sufficient to upregulate a panel of inflammatory cytokines in iBECs. Taken together, these findings show that pneumococcus interacts with and disrupts iBECs during infection, supporting iBECs as an important model for studying pneumococcus-BBB interactions.

Coxsackievirus B3 is a leading cause of viral aseptic meningitis. To gain entry to the central nervous system, it must interact with and disrupt the brain endothelial cells of the blood-brain barrier. Here, we report the global transcriptome of stem-cell-derived brain-like endothelial cells during coxsackievirus B3 infection.

Group B Streptococcus (GBS; Streptococcus agalactiae) is a gram-positive colonizer of the healthy intestinal and genitourinary microbiota. During and shortly after birth, neonates and infants can be opportunistically infected leading to sepsis, pneumonia, or meningitis among other illnesses. GBS is the leading cause of neonatal meningitis globally, and while prophylactic treatments have been successful for reducing early-onset disease, no decrease in the incidence of late-onset disease has occurred and no vaccine is currently available. In this review, we describe GBS both from a clinical and molecular standpoint. We first describe the history of GBS perinatal disease and its clinical presentation and treatment, as well as patient outcomes. We then present recently discovered GBS interactions at the blood-brain barrier that contribute to disease and inflammatory responses, and efforts to develop a broadly effective GBS vaccine.

Coxsackievirus B3 (CVB3) is an enterovirus known to be a leading cause of viral aseptic meningoencephalitis worldwide. Therefore, the virus may interact with and cross the blood-brain barrier (BBB). The BBB is a highly specialized endothelial barrier that helps protect the brain from foreign bodies and infection, primarily being composed of brain endothelial cells. Despite the fact that CVB3 can be fatal, particularly in young children, the mechanism through which CVB3 is able to penetrate the BBB and gain access to the central nervous system is not fully characterized and is poorly understood. However, there are challenges when modeling the BBB, as in vivo modeling has morphological differences and in vitro models tend to fall short when it comes to retaining vital BBB phenotypic properties. Modeling the BBB with induced-pluripotent stem-cell-derived brain-like endothelial cells (iBECs) has been shown to be very promising, as iBECs display and retain brain-like phenotypes and have recently been utilized to model CVB3 infection of the BBB. This chapter describes methodologies using iBECs to study the interaction between CVB3 and the BBB as a meningeal human pathogen, including cell differentiation and maintenance, Western blotting, immunostaining, plaque assays, infection of cells, use of antivirals, and viability assays.

Group B Streptococcus (GBS) is a human pathogen and a leading cause of neonatal meningitis, pneumonia, and sepsis in newborns and adults. Group B Streptococcal meningitis is caused when blood-borne GBS interacts with and disrupts the blood-brain barrier, causing inflammation. The blood-brain barrier (BBB) is comprised of highly specialized brain endothelial cells (BECs) that serve as the interface between the circulation and the central nervous system (CNS), creating a tight endothelial cell barrier. Modeling the BBB using an induced pluripotent stem-cell (iPSC)-derived brain-like endothelial cell model (iBEC) allows for robust expression and retention of BBB phenotypes when compared to other in vitro models. This chapter describes the derivation of iBECs, the culture of GBS, and the use of various molecular biology techniques to closely investigate the host-pathogen interactions between the blood-brain barrier and Group B Streptococcus.

BRCA1/2 genes are considered tumor suppressor genes and help repair damaged DNA. Pathogenic germline mutations of BRCA1/2 genes are the most common hereditary cause of breast cancer and ovarian cancer. It has been established that BRCA1 mutations increase the risk of brain metastasis compared to the BRCA1 wildtype, and once metastasis occurs to the brain the disease is considered uncurable. The blood-brain barrier (BBB) is essential for maintaining and regulating homeostasis of the central nervous system and is composed of highly specialized brain endothelial cells. Using a human induced pluripotent stem cell (hiPSC) based model, we characterized an hiPSC line from an invasive cancer patient harboring a BRCA1 mutation. This patient-derived hiPSC line can be utilized to study BBB properties as after differentiation into brain-like endothelial cells (BECs), BECs derived from this line express BBB markers such as tight junction proteins, and functional efflux transporters. Future application of patient-derived stem cell models could provide a platform to discover genetic predispositions to BBB disruption in individuals with BRCA1 mutations, as well as the potential molecular mechanisms contributing to brain metastasis.

Tight junction complexes are crucial features of brain endothelial cells, as they restrict the paracellular route across the blood-brain barrier. Tight junction disruption has been observed in conjunction with numerous diseases of the CNS. In such cases, the organization or integrity of cell-cell junctions may be analyzed with a variety of automated computer programs that quantitatively assess junction images. Here, we directly compare two previously developed python-based programs-JAnaP and IJOQ- for the semi- or fully automated analysis of tight junctions in human stem cell-derived brain-like endothelial cells. Cells were infected with S. pneumoniae and S. agalactiae to initiate junction disruption, and occludin and ZO-1 were analyzed in mock and infected groups via JAnaP and IJOQ. JAnaP and IJOQ both yielded comparable results for the quantification of tight junction disruption in brain endothelial cells. While JAnaP rendered data at the cellular level and gave more information regarding junction phenotype, IJOQ significantly reduced user time and eliminated potential user bias. Our results suggest that JAnaP and IJOQ are both appropriate for quantifying tight junction integrity in brain endothelial cells, and both may offer distinct advantages depending on their context of use.

The brain endothelial cells (BECs) are essential for protecting the central nervous system (CNS) from xenobiotics and pathogens, including Neisseria meningitidis, while maintaining CNS homeostasis through tight junction (TJ) proteins and specialized transporters. Among these, multidrug resistance (MDR) transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are pivotal in restricting the entry of neurotoxic substances. Although the impact of N. meningitidis infection on BBB TJ is well-documented, its effect on MDR transporters remains largely unexplored. We employed induced pluripotent stem cell-derived brain-like endothelial cells (iBECs) as an in vitro BECs model due to their human-like morphology and expression of junctional proteins and MDR transporters. iBECs were exposed to various N. meningitidis strains, isogenic mutants, heat-inactivated bacteria, conditioned media, or purified capsule polysaccharide (CPS). P-gp and BCRP activities were assessed using intracellular accumulation assays with Rhodamine 123 and Chlorin e6, respectively, in the presence of P-gp inhibitors cyclosporin A and PSC833 and BCRP inhibitor Ko143. Gene expression and protein levels were determined by qPCR and western blotting, and sphingolipid quantification was performed via liquid chromatography tandem-mass spectrometry (LC-MS/MS). Infection of iBECs with N. meningitidis inhibited P-gp activity, whereas BCRP activity remained unaffected. P-gp inhibition occurred without changes in gene expression or protein abundance. Cells infected with N. meningitidis showed reduced efficacy of P-gp inhibitors, an effect not seen with the BCRP inhibitor Ko143. N. meningitidis CPS was identified as a key factor in modulating P-gp activity. Notably, the inhibitory effect of N. meningitidis on P-gp activity was blocked by a specific sphingosine 1-phosphate receptor 1 (S1PR1) antagonist as well as by sphingosine kinase inhibitors, revealing a mechanistic link between S1PR1 signaling and P-gp modulation during infection. Furthermore, S1PR1 was upregulated in infected iBECs. Although LC-MS/MS measurement showed no increase in S1P levels in infected cells compared to uninfected controls, these findings suggest a crucial role for S1PR1 signaling in mediating the observed effects. These findings demonstrate that N. meningitidis infection impairs P-gp function through S1PR1-dependent pathways, suggesting that targeting this signaling cascade may offer a novel therapeutic strategy to preserve BBB integrity during bacterial infections.

OBJECTIVE:To identify characteristics of patients who have poor improvement in symptoms following surgical management of Zenker Diverticulum (ZD). METHODS:Prospective, multicenter cohort study of all individuals enrolled in the Prospective OUtcomes of Cricopharyngeus Hypertonicity (POUCH) Collaborative who underwent surgical repair of ZD between August 2017 and January 2024. Patient demographics, esophagrams, and the 10-item Eating Assessment Tool (EAT-10) pre- and post-procedure were obtained from a REDCap database. t-tests, Wilcoxon rank sum tests, Chi-square or Fisher's exact tests were used to compare the characteristics. Patients with <50% improvement in their EAT-10 scores were deemed surgical nonresponders (SNRs). Those with ≥50% improvement in their EAT-10 scores were deemed surgical responders (SRs). RESULTS:A total of 184 patients were prospectively followed after undergoing either open or endoscopic surgical management. Twenty-two patients (12%) were deemed SNRs. Preoperative presence of a hiatal hernia was statistically significant characteristic between the SNRs (63.6%) and SRs (32.1%) (p = 0.004). Size of the ZD and history of previous ZD surgery was not a significant characteristic. The length of stay and complication rate were not statistically different between the groups. CONCLUSION:Coexistent esophageal pathology may lead to poor symptomatic improvement following ZD surgery. Preoperative workup of other esophageal disorders is recommended to detect likely SNRs. For SNRs, further esophageal workup may be necessary to evaluate for other esophageal causes related to poor symptomatic improvement following ZD surgery. LEVEL OF EVIDENCE:3 Laryngoscope, 134:4897-4902, 2024.

Microbe-induced meningoencephalitis/meningitis is a life-threatening infection of the central nervous system (CNS) that occurs when pathogens are able to cross the blood-brain barrier (BBB) and gain access to the CNS. The BBB consists of highly specialized brain endothelial cells that exhibit specific properties to allow tight regulation of CNS homeostasis and prevent pathogen crossing. However, during meningoencephalitis/meningitis, the BBB fails to protect the CNS. Modeling the BBB remains a challenge due to the specialized characteristics of these cells. In this review, we cover the induced pluripotent stem cell-derived, brain-like endothelial cell model during host-pathogen interaction, highlighting the strengths and recent work on various pathogens known to interact with the BBB. As stem cell technologies are becoming more prominent, the stem cell-derived, brain-like endothelial cell model has been able to reveal new insights in vitro, which remain challenging with other in vitro cell-based models consisting of primary human brain endothelial cells and immortalized human brain endothelial cell lines.

Streptococcus agalactiae (Group B Streptococcus) strain COH1 is a representative strain of serotype III, multi-locus sequence type 17, which is disproportionately associated with neonatal meningitis. Here we report the transcriptome of COH1 when interacting with human brain endothelial cells compared with COH1 alone.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that affects the motor neuron. One aspect of the neuropathology involved in ALS includes increased genomic damage and impaired DNA repair capability. The TAR-DNA binding protein 43 (TDP43) has been associated with both sporadic and familial forms of ALS, and is typically observed as cytosolic mislocalization of protein aggregates, termed TDP43 proteinopathy. TDP43 is a ubiquitous RNA/DNA binding protein with functional implications in a wide range of disease processes, including the repair of DNA double strand breaks (DSBs). While TDP43 is widely known to regulate RNA metabolism, our lab has reported it also functions directly at the protein level to facilitate DNA repair. Here, we show that TDP43 protein interacts with DNA mismatch repair (MMR) proteins MLH1 and MSH6 in a DNA damage-inducible manner. We utilized differentiated SH-SY5Y neuronal cultures to identify this inducible relationship using complimentary approaches of proximity ligation assay (PLA) and co-immunoprecipitation (CoIP) assay. We observed that signals of TDP43 interaction with MLH1 and MSH6 increased significantly following a 2 hr treatment of 10μM methylmethanesulfonate (MMS), a DNA alkylating agent used to induce MMR repair. Likewise, we observed this effect was abolished in cell lines treated with siRNA directed against TDP43. Finally, we demonstrated these protein interactions were significantly increased in lumbar spinal cord samples of ALS-affected patients compared to age-matched controls. These results will inform our future studies to understand the mechanisms and consequences of this TDP43-MMR interaction in the context of ALS affected neurons.