Søren Grubb
@sorengrubb.bsky.social
Biologist👩🔬, physiologist🔬, electrophysiologist⚡, cardiovascular scientist❤️, neuroscientist🧠 #precapillarysphincters #microvasculature #meninges #neurovascularcoupling #pericytes #MICrONS #microglia #macrophages #wasteclearance #aging
🧩 Summary:
✅ #Pericytes have #PrimaryCilia with an arterio-venular gradient🏳️🌈
✅ 🚶♀️🧠 ECs have primary #cilia, 🐁🧠 ECs don’t
✅ EC polarity aligns opposite to #BloodFlow 🧭
❔Lots of open questions about cilia’s role in #NeurovascularCoupling!
Read the full preprint: 🔗 www.biorxiv.org/content/10.1...
🧪🧵8/8
✅ #Pericytes have #PrimaryCilia with an arterio-venular gradient🏳️🌈
✅ 🚶♀️🧠 ECs have primary #cilia, 🐁🧠 ECs don’t
✅ EC polarity aligns opposite to #BloodFlow 🧭
❔Lots of open questions about cilia’s role in #NeurovascularCoupling!
Read the full preprint: 🔗 www.biorxiv.org/content/10.1...
🧪🧵8/8
November 20, 2025 at 9:04 PM
🧩 Summary:
✅ #Pericytes have #PrimaryCilia with an arterio-venular gradient🏳️🌈
✅ 🚶♀️🧠 ECs have primary #cilia, 🐁🧠 ECs don’t
✅ EC polarity aligns opposite to #BloodFlow 🧭
❔Lots of open questions about cilia’s role in #NeurovascularCoupling!
Read the full preprint: 🔗 www.biorxiv.org/content/10.1...
🧪🧵8/8
✅ #Pericytes have #PrimaryCilia with an arterio-venular gradient🏳️🌈
✅ 🚶♀️🧠 ECs have primary #cilia, 🐁🧠 ECs don’t
✅ EC polarity aligns opposite to #BloodFlow 🧭
❔Lots of open questions about cilia’s role in #NeurovascularCoupling!
Read the full preprint: 🔗 www.biorxiv.org/content/10.1...
🧪🧵8/8
🧭 #EndothelialCells are polarized against #BloodFlow direction ⤴️. #Centrioles are consistently upstream of the #nucleus. This polarity persists even in fixed tissue and could serve as a structural marker for flow direction. 📌
🧪🧵7/8
🧪🧵7/8
November 20, 2025 at 9:04 PM
🧭 #EndothelialCells are polarized against #BloodFlow direction ⤴️. #Centrioles are consistently upstream of the #nucleus. This polarity persists even in fixed tissue and could serve as a structural marker for flow direction. 📌
🧪🧵7/8
🧪🧵7/8
😮Surprise: 🚶♀️🧠 #EndothelialCells (EC) have #PrimaryCilia facing the vessel lumen, but 🐁🧠 ECs don’t. ~18% of 🚶♀️🧠 ECs are ciliated, mostly in arteriolar-end capillaries. What do these #cilia sense in the 🩸?
🧪🧵6/8
🧪🧵6/8
November 20, 2025 at 9:04 PM
😮Surprise: 🚶♀️🧠 #EndothelialCells (EC) have #PrimaryCilia facing the vessel lumen, but 🐁🧠 ECs don’t. ~18% of 🚶♀️🧠 ECs are ciliated, mostly in arteriolar-end capillaries. What do these #cilia sense in the 🩸?
🧪🧵6/8
🧪🧵6/8
In 🐁, some #pericyte #PrimaryCilia penetrate #astrocytic #endfeet and reach the #neuropil - sometimes near #synapses! Could these #cilia act as sensory “antennae” 📡for #NeurovascularCoupling?
🧪🧵5/8
🧪🧵5/8
November 20, 2025 at 9:04 PM
In 🐁, some #pericyte #PrimaryCilia penetrate #astrocytic #endfeet and reach the #neuropil - sometimes near #synapses! Could these #cilia act as sensory “antennae” 📡for #NeurovascularCoupling?
🧪🧵5/8
🧪🧵5/8
In 🐁🧠, #ultrastructure shows that #pericyte #cilia are often ensheathed by #astrocytic #endfeet. In 🚶♀️🧠, #astrocytes are swollen and cilia stay confined within the basal lamina. What are they sensing from the astrocytes?
🧪🧵4/8
🧪🧵4/8
November 20, 2025 at 9:04 PM
In 🐁🧠, #ultrastructure shows that #pericyte #cilia are often ensheathed by #astrocytic #endfeet. In 🚶♀️🧠, #astrocytes are swollen and cilia stay confined within the basal lamina. What are they sensing from the astrocytes?
🧪🧵4/8
🧪🧵4/8
🗺️We mapped #MuralCells — including #pericytes and #smoothmuscle — as vectors➡️ to visualize where #PrimaryCilia🌟 occur across the 🐁🧠 #microvasculature.
The result? A striking pattern: #cilia are abundant on #capillaries and #venules, but almost absent on #arterioles.
🧪🧵3/8
The result? A striking pattern: #cilia are abundant on #capillaries and #venules, but almost absent on #arterioles.
🧪🧵3/8
November 20, 2025 at 9:04 PM
🗺️We mapped #MuralCells — including #pericytes and #smoothmuscle — as vectors➡️ to visualize where #PrimaryCilia🌟 occur across the 🐁🧠 #microvasculature.
The result? A striking pattern: #cilia are abundant on #capillaries and #venules, but almost absent on #arterioles.
🧪🧵3/8
The result? A striking pattern: #cilia are abundant on #capillaries and #venules, but almost absent on #arterioles.
🧪🧵3/8
📊 #Pericytes are frequently ciliated in both 🐁 and 🚶♀️🧠—but mostly near #venules and venous-end #capillaries.
Venular mural cells: up to 90% ciliated in 🐁 datasets!
Arteriolar mural cells: almost none.
Why this gradient? Flow, pressure, permeability?
🧪🧵2/8
Venular mural cells: up to 90% ciliated in 🐁 datasets!
Arteriolar mural cells: almost none.
Why this gradient? Flow, pressure, permeability?
🧪🧵2/8
November 20, 2025 at 9:04 PM
📊 #Pericytes are frequently ciliated in both 🐁 and 🚶♀️🧠—but mostly near #venules and venous-end #capillaries.
Venular mural cells: up to 90% ciliated in 🐁 datasets!
Arteriolar mural cells: almost none.
Why this gradient? Flow, pressure, permeability?
🧪🧵2/8
Venular mural cells: up to 90% ciliated in 🐁 datasets!
Arteriolar mural cells: almost none.
Why this gradient? Flow, pressure, permeability?
🧪🧵2/8
New on bioRxiv! 🚨
“Pericyte and Endothelial Primary Cilia and Centrioles have Disparate Organization Across the Brain Microvasculature”
This project studying #microvascular cells took an unexpected turn when we discovered that #pericytes have primary #cilia!
🔗 www.biorxiv.org/content/10.1...
🧪 🧵1/8
“Pericyte and Endothelial Primary Cilia and Centrioles have Disparate Organization Across the Brain Microvasculature”
This project studying #microvascular cells took an unexpected turn when we discovered that #pericytes have primary #cilia!
🔗 www.biorxiv.org/content/10.1...
🧪 🧵1/8
November 20, 2025 at 9:04 PM
New on bioRxiv! 🚨
“Pericyte and Endothelial Primary Cilia and Centrioles have Disparate Organization Across the Brain Microvasculature”
This project studying #microvascular cells took an unexpected turn when we discovered that #pericytes have primary #cilia!
🔗 www.biorxiv.org/content/10.1...
🧪 🧵1/8
“Pericyte and Endothelial Primary Cilia and Centrioles have Disparate Organization Across the Brain Microvasculature”
This project studying #microvascular cells took an unexpected turn when we discovered that #pericytes have primary #cilia!
🔗 www.biorxiv.org/content/10.1...
🧪 🧵1/8
🎥 NAD 2025 Annual Meeting Highlights
From Oct 3–5, Neuroscience Academy Denmark hosted:
✅ 400+ participants
✅ 100 posters
✅ Keynotes on precision psychiatry, brain barriers, ultrasound treatments, brain stimulation, sleep & circadian rhythms
We look forward to next year!
#Neuroscience #NAD2025 🧪
From Oct 3–5, Neuroscience Academy Denmark hosted:
✅ 400+ participants
✅ 100 posters
✅ Keynotes on precision psychiatry, brain barriers, ultrasound treatments, brain stimulation, sleep & circadian rhythms
We look forward to next year!
#Neuroscience #NAD2025 🧪
November 14, 2025 at 12:59 PM
🎥 NAD 2025 Annual Meeting Highlights
From Oct 3–5, Neuroscience Academy Denmark hosted:
✅ 400+ participants
✅ 100 posters
✅ Keynotes on precision psychiatry, brain barriers, ultrasound treatments, brain stimulation, sleep & circadian rhythms
We look forward to next year!
#Neuroscience #NAD2025 🧪
From Oct 3–5, Neuroscience Academy Denmark hosted:
✅ 400+ participants
✅ 100 posters
✅ Keynotes on precision psychiatry, brain barriers, ultrasound treatments, brain stimulation, sleep & circadian rhythms
We look forward to next year!
#Neuroscience #NAD2025 🧪
That reminds me of Thor fighting “midgårdsormen” the world serpent 🤣
September 27, 2025 at 8:31 AM
That reminds me of Thor fighting “midgårdsormen” the world serpent 🤣
The first Master’s student with me as main supervisor graduated today! I’m proud 🥹
June 24, 2025 at 5:37 PM
The first Master’s student with me as main supervisor graduated today! I’m proud 🥹
Using #InVivo #VolumeImaging, we found #age related #vascular changes:
• ↑ #Tortuosity of #PenetratingArterioles
• ↓ #Arteriolar-capillary density
• ↑ #Capillaries at the venous end + #aneurysm-like bulbs downstream of #PrecapillarySphincters.
• ↑ #Tortuosity of #PenetratingArterioles
• ↓ #Arteriolar-capillary density
• ↑ #Capillaries at the venous end + #aneurysm-like bulbs downstream of #PrecapillarySphincters.
June 10, 2025 at 7:38 PM
Using #InVivo #VolumeImaging, we found #age related #vascular changes:
• ↑ #Tortuosity of #PenetratingArterioles
• ↓ #Arteriolar-capillary density
• ↑ #Capillaries at the venous end + #aneurysm-like bulbs downstream of #PrecapillarySphincters.
• ↑ #Tortuosity of #PenetratingArterioles
• ↓ #Arteriolar-capillary density
• ↑ #Capillaries at the venous end + #aneurysm-like bulbs downstream of #PrecapillarySphincters.
By recording #cortical #angiograms during i.v. injection of FITC-dextran 🟢 in #adult and #old #NG2DsRed mice, we time-colored the #arterioles 🔴 and #venules 🔵. We found that #OldMice have less #collaterals and more #tortuous #PenetratingArterioles.
June 10, 2025 at 7:38 PM
By recording #cortical #angiograms during i.v. injection of FITC-dextran 🟢 in #adult and #old #NG2DsRed mice, we time-colored the #arterioles 🔴 and #venules 🔵. We found that #OldMice have less #collaterals and more #tortuous #PenetratingArterioles.
After #LaserAblating pericytes around #PrecapillarySphincters, we observed impaired #MyogenicResponse and #NeurovascularCoupling—demonstrating #PrecapillarySphincter pericyte contractility is essential.
June 10, 2025 at 7:38 PM
After #LaserAblating pericytes around #PrecapillarySphincters, we observed impaired #MyogenicResponse and #NeurovascularCoupling—demonstrating #PrecapillarySphincter pericyte contractility is essential.
#OldMice also showed decreased pulsations of microvessel diameters measured by transverse line scans, likely due to #VascularStiffening.
June 10, 2025 at 7:38 PM
#OldMice also showed decreased pulsations of microvessel diameters measured by transverse line scans, likely due to #VascularStiffening.
In aged mice, the #MyogenicResponse was significantly blunted. This was shown by an increased #CorrelationCoefficient (CC) between #VascularDiameter and #BloodPressure
June 10, 2025 at 7:38 PM
In aged mice, the #MyogenicResponse was significantly blunted. This was shown by an increased #CorrelationCoefficient (CC) between #VascularDiameter and #BloodPressure
We challenged mice with acute #BloodPressure spikes (~70% increase via angiotensin II). Result: both adult and #old mice got their #MyogenicResponse and #NeurovascularCoupling disrupted
June 10, 2025 at 7:38 PM
We challenged mice with acute #BloodPressure spikes (~70% increase via angiotensin II). Result: both adult and #old mice got their #MyogenicResponse and #NeurovascularCoupling disrupted
To visualize this, we used #InVivo #TwoPhotonMicroscopy in anesthetized adult and aged mice. Watch this video showing PS dilation in response to “SensoryStimulation! 🔬👇
June 10, 2025 at 7:38 PM
To visualize this, we used #InVivo #TwoPhotonMicroscopy in anesthetized adult and aged mice. Watch this video showing PS dilation in response to “SensoryStimulation! 🔬👇
🐭🧠 #PrecapillarySphincters (PS) at the #arteriole–#capillary junction rapidly dilate ~30% in seconds during #SensoryStimulation—regulating #capillary #BloodFlow dynamically. Here we investigated whether they protect downstream microvessels during abrupt #BloodPressure surges 🧪🧵
June 10, 2025 at 7:38 PM
🐭🧠 #PrecapillarySphincters (PS) at the #arteriole–#capillary junction rapidly dilate ~30% in seconds during #SensoryStimulation—regulating #capillary #BloodFlow dynamically. Here we investigated whether they protect downstream microvessels during abrupt #BloodPressure surges 🧪🧵
Playing around with my 3yo daughter and an antique microscope. Looked at some #dandelion petals and a stamen using a Carl Zeiss P.A. 35 microscope using reflected light. 🧪
May 2, 2025 at 4:52 PM
Playing around with my 3yo daughter and an antique microscope. Looked at some #dandelion petals and a stamen using a Carl Zeiss P.A. 35 microscope using reflected light. 🧪
Thanks! We used potassium acetate to induce the CSD. Remember that even a small contraction of a precapillary sphinter (3-4um in diameter) gives a high increase in resistance.
November 30, 2024 at 8:47 PM
Thanks! We used potassium acetate to induce the CSD. Remember that even a small contraction of a precapillary sphinter (3-4um in diameter) gives a high increase in resistance.
Here we show how 🧠 #precapillarysphincters react to #CorticalSpreadingDepolarization which is associated with #migraine with #aura 🤕. #CSD has 3 phases: constriction, dilation, and a long lasting constriction that interrupts #bloodflow🩸 to #capillaries (Tinyurl.com/euasfses).
November 30, 2024 at 12:54 PM
Here we show how 🧠 #precapillarysphincters react to #CorticalSpreadingDepolarization which is associated with #migraine with #aura 🤕. #CSD has 3 phases: constriction, dilation, and a long lasting constriction that interrupts #bloodflow🩸 to #capillaries (Tinyurl.com/euasfses).
#Neurovasculature changes from the #arterial to the #venular end. Here I have tried to draw the #cell morphologies realistically. #Endothelialcells go from spindle shaped to rhombic shaped and #muralcells from #smoothmuscle to #pericytes. #Astrocytes same shape. www.sciencedirect.com/science/arti...
November 29, 2024 at 2:49 PM
#Neurovasculature changes from the #arterial to the #venular end. Here I have tried to draw the #cell morphologies realistically. #Endothelialcells go from spindle shaped to rhombic shaped and #muralcells from #smoothmuscle to #pericytes. #Astrocytes same shape. www.sciencedirect.com/science/arti...
Here is a #precapillarysphincter. As #arterioles 🟢 dive into the 🧠, they branch to smaller vessels. When larger arterioles (15-25um) branch into #capillaries, they need a #sphincter (3-4um) to reduce #RBC flow⚫️ and pressure in the #capillary. The resistance is provided by #muralcell🔴 encirclement.
November 28, 2024 at 5:05 PM
Here is a #precapillarysphincter. As #arterioles 🟢 dive into the 🧠, they branch to smaller vessels. When larger arterioles (15-25um) branch into #capillaries, they need a #sphincter (3-4um) to reduce #RBC flow⚫️ and pressure in the #capillary. The resistance is provided by #muralcell🔴 encirclement.