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Dimeric basic leucine zipper (bZIP) proteins are conserved transcriptional enhancers found in all eukaryotes. A recently reported and novel function for bZIPs is association of these proteins with secondary metabolite production in filamentous fungi. In particular a Yap-like bZIP termed RsmA (restorer of secondary metabolism A) was identified in Aspergillus nidulans that positively regulates the carcinogen sterigmatocystin. To assess for conserved function for RsmA, we examined a role of this protein in secondary metabolism in the pathogen A. fumigatus. RsmA was found to positively regulate gliotoxin where overexpression (OE) of rsmA led to 2–100 fold increases of twelve gli cluster metabolites in culture medium including the newly identified gli metabolite cyclo(L-Phe-L-Ser). Lungs from both wild type and OErsmA infected mice contained gliotoxin (2.3 fold higher in OErsmA treatment) as well as the gliotoxin precursor cyclo(L-Phe-L-Ser) (3.2 fold higher in OErsmA treatment). The data here presents a conserved role for RsmA in secondary metabolite cluster activation and suggests cyclo(L-Phe-L-Ser) may serve as an alternative marker for diagnosis of invasive aspergillosis. [ABSTRACT FROM AUTHOR]

Kostmann disease is an inherited severe congenital neutropenia syndrome associated with loss-of-function mutations in an adaptor protein HS1-associated protein X-1 (Hax1). How Hax1 regulates neutrophil function remains largely unknown. In this paper, we use ribonucleic acid interference to deplete Hax1 in the neutrophil-like cell line PLB-985 and identify Hax1 as a negative regulator of integrin-mediated adhesion and chemotaxis. Using microfluidics, we show that depletion of Hax1 impairs neutrophil uropod detachment and directed migration. Hax1-deficient cells also display increased integrin-mediated adhesion and reduced RhoA activity. Moreover, depletion of RhoA induces increased neutrophil adhesion and impaired migration, suggesting that Hax1 regulates neutrophil adhesion and chemotaxis through RhoA. Accordingly, activation of RhoA is sufficient to rescue adhesion of Hax1-deficient neutrophils. Together, our findings identify Hax1 as a novel regulator of neutrophil uropod detachment and chemotaxis through RhoA. [ABSTRACT FROM AUTHOR]

Trigger valves are fundamental features in capillary-driven microfluidic systems that stop fluid at an abrupt geometric expansion and release fluid when there is flow in an orthogonal channel connected to the valve. The concept was originally demonstrated in closed-channel capillary circuits. We show here that trigger valves can be successfully implemented in open channels. We also show that a series of open-channel trigger valves can be placed alongside or opposite a main channel resulting in a layered capillary flow. We developed a closed form model for the dynamics of the flow at trigger valves based on the concept of average friction length and successfully validated the model against experiments. For the main channel, we discuss layered flow behavior in the light of the Taylor-Aris dispersion theory and in the channel turns by considering Dean theory of mixing. This work has potential applications in autonomous microfluidics systems for biosensing, at-home or point-of-care sample preparation devices, hydrogel patterning for 3D cell culture and organ-on-a-chip models., Competing Interests: A.B.T. reports filing multiple patents through the University of Washington and A.B.T. received a gift to support research outside the submitted work from Ionis Pharmaceuticals. E.B. is an inventor on multiple patents filed by Tasso, Inc., the University of Washington, and the University of Wisconsin-Madison. T.M.N. has ownership in Tasso, Inc.; E.B. has ownership in Tasso, Inc., Salus Discovery, LLC, and Seabright, LLC and is employed by Tasso, Inc.; and A.B.T. has ownership in Seabright, LLC; however, this research is not related to these companies. The terms of this arrangement have been reviewed and approved by the University of Washington in accordance with its policies governing outside work and financial conflicts of interest in research. The other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Sperm cryopreservation is important for many individuals across the globe. Recent studies show that vitrification is a valuable approach for maintaining sperm quality after freeze-thawing processes and requires sub-microliter to microliter volumes. A major challenge for the adoption of vitrification in fertility laboratories is the ability to pipette small volumes of sample. Here, we present an open droplet generator that leverages open-channel microfluidics to passively generate sub-microliter to microliter volumes of purified human sperm samples and preserves sperm kinematics. We conclude that our platform is compatible with human sperm, an important foundation for future implementation of vitrification in fertility laboratories., Competing Interests: T.M.N., J.W.K., U.N.L., E.B., and A.B.T. filed patent Open Microfluidic Channel Design for Passive Droplet Formation and Manipulation May 23, 2022 through the University of Washington. A.B.T. and U.N.L. report filing multiple patents through the University of Washington and A.B.T. received a gift to support research outside the submitted work from Ionis Pharmaceuticals. E.B. is an inventor on multiple patents filed by Tasso, Inc., the University of Washington, and the University of Wisconsin-Madison. T.M.N. has ownership in Tasso, Inc.; E.B. has ownership in Tasso, Inc., Salus Discovery, LLC, and Seabright, LLC and is employed by Tasso, Inc.; and A.B.T. has ownership in Seabright, LLC; however, this research is not related to these companies. The terms of this arrangement have been reviewed and approved by the University of Washington in accordance with its policies governing outside work and financial conflicts of interest in research. The other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Extracellular Vesicles (EVs) are membrane-derived vesicles shed by cells into the extracellular space that play key roles in intercellular communication and other biological processes. As membrane-bound cargos of nucleic acids and other proteins that are abundantly found in virtually every biofluid including blood, urine, and saliva, EVs are widely regarded as promising biomarkers for disease detection. While it is an increasingly promising biofluid from which to isolate EVs, saliva poses challenges due its complexity and heterogeneity-cells, debris, and other proteins can inhibit the isolation of EVs by traditional platforms. Here, we employ the CandyCollect, a lollipop-inspired sampling device with open microfluidic channels, as a non-invasive and patient-friendly alternative for the capture of salivary EVs. The CandyCollect simplifies sample preparation by effectively pre-concentrating EVs on the device surface before EVs are eluted off of the CandyCollect, labeled with cholesterol-tagged oligonucleotides, and subsequently detected by qPCR with primers specific for the tagged oligos to enumerate the relative number of EVs. We demonstrate that downstream EV cargo analysis can be performed using Simoa. Overall, the CandyCollect ushers a new method to capture, enumerate, and analyze salivary EVs.

Cell-laden hydrogel constructs suspended between pillars are powerful tools for modeling tissue structure and physiology, though current fabrication techniques often limit them to uniform compositions. In contrast, tissues are complex in nature with spatial arrangements of cell types and extracellular matrices. Thus, we present Suspended Tissue Open Microfluidic Patterning (STOMP), which utilizes a removable, open microfluidic patterning channel to pattern multiple spatial regions across a single suspended tissue. The STOMP platform contains capillary pinning features along the open channel that controls the fluid front, allowing multiple cell and extracellular matrix precursors to be pipetted into one tissue. We have used this technique to pattern suspended tissues with multiple regional components using a variety of native and synthetic extracellular matrices, including fibrin, collagen, and poly(ethylene glycol). Here, we demonstrate that STOMP models a region of fibrosis in a functional heart tissue and a bone-ligament junction in periodontal tissues. Additionally, the STOMP platform can be customized to allow patterning of suspended cores and more spatial configurations, enhancing its utility in complex tissue modeling. STOMP is a versatile technique for generating suspended tissue models with increased control over cell and hydrogel composition to model interfacial tissue regions in a suspended tissue., Competing Interests: Conflicts of interest AJH, LGB, AJG, PM, ARV, TPL, SHN, AL, JMW, RCB, EB, CAD, NJS, and ABT filed patent 18/669,367 and AJH, LGB, JMW, ARV, CAD, NJS, EEB, EB, and ABT filed patent 63/665,194 through the University of Washington on STOMP and a related technology. ABT reports filing multiple patents through the University of Washington and receiving a gift to support research from Ionis Pharmaceuticals. EB and ABT have ownership in Seabright, LLC, which will advance new tools for diagnostics and clinical research. EB has ownership in Salus Discovery, LLC, and Tasso, Inc. and is employed by Tasso, Inc. NJS has ownership in Stasys Medical Corporation, Inc. and has ownership and is a scientific advisor in Curi Bio, Inc. Technologies from Salus Discovery, LLC, Tasso, Inc., Stasys Medical Corporation, Inc, and Curi Bio, Inc. are not included in this publication. EB is an inventor on multiple patents filed by Tasso, Inc., the University of Washington, and the University of Wisconsin-Madison. The terms of this arrangement have been reviewed and approved by the University of Washington in accordance with its policies governing outside work and financial conflicts of interest in research.

Remote research studies are an invaluable tool for reaching populations in geographical regions with limited access to large medical centers or universities. To expand the remote study toolkit, we have previously developed homeRNA, which allows for at-home self-collection and stabilization of blood and demonstrated the feasibility of using homeRNA in high temperature climates. Here, we expand upon this work through a systematic study exploring the effects of high temperature on RNA integrity through in-lab and field experiments. Compared to the frozen controls (overall mean RIN of 8.2, n = 8), samples kept at 37°C for 2, 4, and 8 days had mean RINs of 7.6, 5.9, and 5.2 ( n = 3), respectively, indicating that typical shipping conditions (~2 days) yield samples suitable for downstream RNA sequencing. Shorter time intervals (6 hours) resulted in minimal RNA degradation (median RIN of 6.4, n = 3) even at higher temperatures (50°C) compared to the frozen control (mean RIN of 7.8, n = 3). Additionally, we shipped homeRNA-stabilized blood from a single donor to 14 different states and back during the summer with continuous temperature probes (7.1 median RIN, n = 42). Samples from all locations were analyzed with 3' mRNA-seq to assess differences in gene counts, with the transcriptomic data suggesting that there was no preferential degradation of transcripts as a result of different shipping times, temperatures, and regions. Overall, our data support that homeRNA can be used in elevated temperature conditions, enabling decentralized sample collection for telemedicine, global health, and clinical research., Competing Interests: Conflicts of Interest EB, AJH, and ABT filed patent 17/361,322 (Publication Number: US20210402406A1) and EB, AJH, ABT, and FS filed patent 63/571,012 through the University of Washington on homeRNA and a related technology. ABT reports filing multiple patents through the University of Washington and receiving a gift to support research outside the submitted work from Ionis Pharmaceuticals. EB has ownership in Salus Discovery, LLC, and Tasso, Inc. that develops blood collection systems used in this manuscript, and is employed by Tasso, Inc. Technologies from Salus Discovery, LLC are not included in this publication. He is an inventor on multiple patents filed by Tasso, Inc., the University of Washington, and the University of Wisconsin-Madison. The terms of this arrangement have been reviewed and approved by the University of Washington in accordance with its policies governing outside work and financial conflicts of interest in research. LGB, SN, and AJH have also filed additional patents through the University of Washington outside the scope of this publication.

Endothelial cells (ECs) from different human organs possess organ-specific characteristics that support specific tissue regeneration and organ development. EC specificity is identified by both intrinsic and extrinsic cues, among which the parenchyma and organ-specific microenvironment are critical contributors. These extrinsic cues are, however, largely lost during ex vivo cultures. Outstanding challenges remain to understand and reestablish EC organ specificity for in vitro studies to recapitulate human organ-specific physiology. Here, we designed an open microfluidic platform to study the role of human kidney tubular epithelial cells in supporting EC specificity. The platform consists of two independent cell culture regions segregated with a half wall; culture media are added to connect the two culture regions at a desired time point, and signaling molecules can travel across the half wall (paracrine signaling). Specifically, we report that in the microscale coculture device, primary human kidney proximal tubule epithelial cells (HPTECs) rescued primary human kidney peritubular microvascular EC (HKMEC) monolayer integrity and fenestra formation and that HPTECs upregulated key HKMEC kidney-specific genes (hepatocyte nuclear factor 1 homeobox B, adherens junctions-associated protein 1, and potassium voltage-gated channel subfamily J member 16) and endothelial activation genes (vascular cell adhesion molecule-1, matrix metalloproteinase-7, and matrix metalloproteinase-10) in coculture. Coculturing with HPTECs also promoted kidney-specific genotype expression in human umbilical vein ECs and human pluripotent stem cell-derived ECs. Compared with culture in HPTEC conditioned media, coculture of ECs with HPTECs showed increased upregulation of kidney-specific genes, suggesting potential bidirectional paracrine signaling. Importantly, our device is compatible with standard pipettes, incubators, and imaging readouts and could also be easily adapted to study cell signaling between other rare or sensitive cells.